CN101790955B - Method for controlling irrigation according to crop water shortage degree and device thereof - Google Patents

Abstract

The invention relates to a method for controlling irrigation according to crop water shortage degree and a device thereof. The method comprises the following steps of: determining a detection time window according to an illumination threshold and an illumination integral threshold; after entering the detection time window, simultaneously emitting ultrasonic waves to ultrasonic reflecting boards which are arranged in right front at equal intervals respectively from the positions approximately above the reference crop and the detection crop and parallel to the planes of the respective crops below at preset time intervals; when receiving the respective reflected ultrasonic waves, respectively starting and stopping the same counter; comparing the counting value with the counting threshold set according to the crop water shortage index in the ultrasonic transition time; and if the counting value is smaller than the counting threshold, the crop water shortage degree requires irrigation, then starting irrigation. The invention has the advantages of fewer detection parameters, no complicated calculation, no detection individual difference, non-contact measurement, and high economy and practicality.

Description

Control is irrigated according to crop water shortage degree method and device thereof

Technical field:

The invention belongs to agricultural irrigation technology, particularly relate to a kind of control is irrigated according to crop water shortage degree method and device thereof.

Background technology:

Crop growth needs numerous envirment factors, is referred to as to coerce when deposits yields injures effect to doing when these envirment factors change.Crop often suffers multiple environment-stress in process of growth.Studies confirm that water deficit surpasses every other summation of coercing to the influence of crop growth and output.Therefore water is the important foundation resource of agricultural production, and the management of crop water is one of of paramount importance measure in the crop production.In general, (0～90cm), its soil moisture content is 60%～80% of a field capacity to the root zone according that suitable crop normal growth is grown, if should in time irrigate when being lower than this water content.Soil moisture content has certain reference value to irrigation, and is used widely in the crop water-saving irrigation.But since irrigate to as if crop, rather than soil does not utilize crop itself to need water information as the direct foundation of irrigating, and does not therefore really reach the demand water supply according to crop.

Improving natural precipitation and irrigation water utilization ratio is the core of water-saving agriculture, and the research emphasis of water-saving agricultural technology tilts to agronomy water saving, biological (physiology) water saving direction from the engineering water saving.The central idea of biological water saving is: adopt scientific method, break through the irrigation pattern of traditional " capacity in time ", supply water according to crop water consumption and water utilization rule timely and appropriate discovery, promptly when satisfying the plant physiology needs, reduce rising consumption of moisture luxury of crop, according to each physiology course of crop and the sensitivity of each growing stage to moisture, determine the demand of crop to soil moisture, improve crop water production efficiency.For a long time, Chinese scholars has been carried out a large amount of research work aspect biological water-saving technology.People directly utilize or the physiological change of indirect reference crop is inquired into the need water information of crop, have successively studied many wane methods of diagnosis of crop water that are used for.But forefathers' work mainly is: the Changing Pattern of the caused plant physiology of water deficit, and concentrate on the statistics of theory analysis and experimental data.All there is such or such deficiency in the method for diagnosis because these crop waters wane, thereby the physical signs of plant needed the water information decision as plant and be applied in the actual irrigation control still rare, except that case, product that can sizable application does not almost have.Past according to this below achievement in research is summarized as follows with regard to the wane benefit and limitation of diagnosis index, method of different crop waters:

1, crop pattern: the form of crop water shortage mainly shows two aspects: the one, and leaf area index descends; The 2nd, blade generation metamorphosis is wilted as blade; Blade changes the orientation; Change the leaf angle and change leaf color etc.Though morphological index can be used to differentiate the water deficit of crop, lack of water and the crop pattern that causes change a lag period, when occurring above-mentioned lack of water symptom on the form, has been subjected to injury to a certain degree on the physiology.Lack of water is not the sole cause that causes crop pattern to change in addition, changes yet very difficult its degree of water shortage that quantizes even monitored crop pattern.

2, plant water potential: the mensuration of plant water potential is considered to understand the plant moisture direct method of degree that wanes, but directly measures the leaf water potential detection of need exsomatizing, and plant corpus is had destructiveness.Can the indirect determination plant water potential by measuring plant haulm diameter or vane thickness microvariations, though plant corpus is not had destructiveness, there is entity contact with plant, influenced by plant growing, need often to calibrate, be not suitable for long-term observation.The dynamic hydraulic characteristic(s) of plant organ will reduce measuring reliability and feasibility over time.Measurement mechanism is attached to coming off easily on the plant corpus, and disturbance rejection is poor, exists to detect individual difference.

3, stomatal conductance: when plant hydropenia, moisture becomes the deciding factor of decision stomatal movement, and arid can cause stomatal closure, thereby avoids damaging because of continuing a large amount of rising dehydrations.Directly measuring stomatal conductance needs manual operations, has entity to contact with plant, is being difficult to realize in the irrigation decision in real time.Crop absorbs 99% of moisture and is used for the blade face transpiration, and pore is the passage that plant transpiration institute must process.Stomatal conductance is big, and is rising just strong; Otherwise just.Detecting the blade face transpiration can the indirect determination stomatal conductance, by measure plant stem flow change can the indirect detection blade face rising and then detect stomatal conductance and change, but this method apparatus expensive, operation easier is big, has entity contact with plant and has the detection individual difference.According to conservation of energy principle, leaf temperature is the result of environment and inside plants factors blade energy balance, and the crop water that changes based on the Ye Wen diagnosis index that wanes more can reflect the water deficit situation of crop all sidedly.When the crop water supply reduced, the latent heat of crop transpiration reduced sensible heat and increases, and the corresponding rising of leaf temperature, the variation of Ye Wen have reflected the variation of blade face transpiration indirectly.The measurement of Ye Wen is undertaken by contact or noncontact mode, uses tiny thermocouple wire to insert plant leaf vein or is attached on the blade face, is difficult to implementation in crop is commercially produced.The non-contacting infrared temperature sensor of general use adopts canopy-air temperature difference or CWSI (crop water is coerced index) as the lack of water judge index.It is the control method of irrigation that is considered to have most Commercial Prospect up to now.Domestic existing patent, for example: 200,710,178,192 1 kinds of online crop water stress irrigation decision monitoring systems of application number.

4, photosynthetic rate: compel down at serious moisture rib, photosynthesis of plant is suppressed or suppresses fully.But test photosynthetic rate program is too complicated, only is suitable for scientific research.

5, cell sap concentration: from the plant physiology arid plant body fluid physicochemical property is changed, body fluid enrichment, leaf water potential increase and can reflections to some extent on the physiology electrical characteristics.Survey corn stem physiology resistance with cover pin type electric resistance sensor, survey maize leaf physiology electric capacity, can both accurately reflect the plant water regime in real time with change in dielectric constant type parallel flat capacitance sensor.But there is entity to contact with plant, the influence position normal physiological function of surveying, unsuitable long-term observation, measurement mechanism inserts or attached on the plant corpus, disturbance rejection is poor, exists to detect individual difference.

6, acoustic information: according to moisture transportation cohesive force theory, crop cohesive force between the hydrone in the plant corpus when water stress lost efficacy or the adhesive force of catheter wall was lost efficacy, take place to rupture or find time, be the cavitation of plant xylem, can realize that crop is looked feelings to be irrigated and regulate by the Crop Information that the sound reception sensor is obtained.But relevant mechanism particularly quantizating index need further be studied and improved, and has entity to contact with plant, and measurement mechanism is attached on the plant corpus, and disturbance rejection is poor, exists to detect individual difference.

The above-mentioned crop water diagnosis index that wanes can be divided into two kinds of form and physical signs, the plant physiology index to the susceptibility of responding to water deprivation significantly better than the crop pattern index.The water deficiency diagnosis method that has entity to contact with plant, though Theoretical Framework is all very complete, and can reduce the influence that detects individual difference by increasing sensor kind (many indexs) or quantity (multiple spot position), promote but under the commercial crop condition of production of volume production scale, be difficult to implement.So research and develop contactlessly, plant corpus can be suffered the method for sensing of the elimination individual difference that the physiological signal of lack of water adverse circumstance the quantized special needs that seem, contactlessly will favor by the user and be easy to commercialization and promote.

Contactlessly mainly study at present from following two aspects: the one, application image and spectral technique carry out the technology of crop water shortage information diagnosis, and domestic and international research is all underway.The crop pattern variation lags behind the main bottleneck that crop water shortage is still this kind technology, and this kind technology more is applicable to damage caused by a drought monitoring remote sensing; Two are based on the infrared temperature sensing technology, reflect that by the crop canopies surface temperature crop water shortage situation is a relatively active research field always, since the sixties in 20th century just.Research mainly concentrates on the yardstick of field, the core of its technical system is to utilize the relation of infrared radiation thermometer research crop canopies temperature or canopy-air temperature difference and plant growth and lack of water index, the empirical mode by crop water being coerced index (CWSI) and the research of theoretical pattern, propose the index of reflection crop water shortage situation, be used for farmland moisture and irrigate and manage.From external present result of study, infrared temperature is a more promising crop water situation diagnostic signal.Utilize infrared temperature-test technology diagnosis crop water shortage situation that many-sided advantage is arranged: measure fast, easy and simple to handle, do not hinder and damage sample, can automatic monitor for continuously.This method has overcome the big drawback of sampling error when being the fundamental surveillance unit with single blade or individual plant crop, therefore is highly suitable for field crop.Following 3 kinds of methods are generally arranged: the one, crop canopies blade face temperature method.The crop canopies temperature is the result that environment (atmosphere, soil moisture) and plant corpus internal factor influence the canopy energy balance jointly, the crop canopies temperature is relevant with the absorption and the dispose procedure of energy, crop canopies absorbs solar radiant energy, this power conversion becomes heat energy, the crop transpiration will consume a part of heat energy, and remaining heat energy can make canopy surface temperature raise.Therefore, the crop canopies temperature under the high-moisture condition is lower, under the low moisture condition, and rising can the minimizing, the latent heat that is consumed also can reduce, and sensible heat increases, and the crop canopies temperature can increase.Wanjura DF (1995) etc. control irrigation by measuring 1 day middle cotton corolla layer temperature above 28 ℃ time number.Similar with it representative index mainly contains coerces accumulated temperature SDD (Stress Degree Day), canopy surface temperature variability CTV (Canopy Temperature Variability) and temperature is coerced a day TSD (Temperature Stress Day) etc.The common feature of these indexs be by consider the crop canopies temperature in time on (as SDD, TSD) or the space variation characteristic of (as CTV) reflect the water regime of crop.Because canopy surface temperature is the result of energy balance in the field ecosystem, the variation of canopy surface temperature not merely is subjected to what influence of soil moisture, and is therefore unsatisfactory in actual applications by the index that single canopy surface temperature is set up; The 2nd, with the water deficit state of crop canopy surface temperature and temperature difference index reaction crop.A lot of researchs think that the temperature difference (Tc-Ta) of crop canopies and canopy upper air and crop water supply condition are closely related, and are general because the transpiration of time-division at noon is the strongest, Tc-Ta difference maximum, and canopy-air temperature difference at this moment can react the water supply state of crop.Because the cooling effect of crop canopies transpiration, the Tc-Ta of lack of water crop is not generally negative value, occurs beginning lack of water on the occasion of general expression crop.But some studies show that, generally replace the temperature on canopy top to calculate canopy-air temperature difference with the temperature in the thermometer screen, because the former measurement is easier than the latter.The temperature that replaces canopy top with the temperature in the thermometer screen, the variation of its canopy-air temperature difference rises and falls very big, particularly summer, radiation was strong, the atmospheric temperature on canopy top may be than the temperature height in the thermometer screen, therefore replace the temperature on canopy top with the temperature in the thermometer screen, the canopy-air temperature difference that makes calculating is on the occasion of on the high side.For the summer corn of abundant water supply, the temperature difference of canopy surface temperature and thermometer screen is mostly below 1.5 ℃, 1.5 ℃ of canopy-air temperature differences as the index that instructs summer corn to pour water.This method is affected by environment, and lack of water threshold value discreteness is bigger, general less independent employing.For example: the mode that the smart amount control in proving ground, China Water Resources ﹠ Hydropower Science Research Institute Daxing irrigation tests district has just adopted canopy-air temperature difference to combine with the soil moisture index; Three are to use crop water to coerce index CWSI (Crop WaterStress Index) instructs irrigation time.At present, using crop water to coerce index CWSI (Crop WaterStress Index), to instruct irrigation time be a kind of important means.1981, Idso at first proposed to coerce index CWSI (Crop Water Stress Index) based on the crop water of empirical mode, the degree that wanes that the maximum evapotranspiration of crop when CWSI may be defined as actual evapotranspiration with moisture supply abundance is compared.

$\mathrm{CWSI}=1-\frac{{\mathrm{ET}}_a}{{\mathrm{ET}}_p}---(1-1)$

ET wherein _aBe actual evapotranspiration (mm/d); ET _pBe possible (potential) evapotranspiration (mm/d).Cover better crop, have only the sub-fraction energy to be used under the situation of soil evaporation, CWSI also has another form:

$\mathrm{CWSI}=1-\frac{T}{T_P}---(1-2)$

(1-2) formula has been taken all factors into consideration the factor of soil, crop and external environment, is considered to one of comparatively ideal index, but also there is shortcoming in it, promptly adopts Peng Man-Munster's formula to calculate transpiration rate (T) and potential transpiration speed (T _P) time, only considered the pore diffusional resistance, and do not considered the variation of resistance on the water-flowing path, and this resistance is engraved in variation when being.This contextual definition when Idso etc. will fully supply water between canopy-air temperature difference (Tc-Ta) and the water-vapo(u)r saturation poor (VPD) is following baseline.Along with the aggravation of water stress, (Tc-Ta) become big and be positioned at down on the baseline, when transpiration stops fully, (Tc-Ta) will reach a limiting value, Idso is defined as baseline with this limiting value.The water regime key of utilizing the crop water of Idso to coerce index quantification diagnosis crop is to determine the following baseline under the abundant water supply conditions.Baseline determines to also have theoretical pattern except that empirical mode up and down.

1, empirical mode: Idso S B equals to consider to influence in 1981 the main environment factor air humidity of crop canopies variations in temperature, has proposed crop water stress index CWSI.This index is based on an important empirical relation, and promptly crop poor (abbreviation canopy-air temperature difference) of crop canopies temperature and air themperature under (or potential evaporation) condition of fully pouring water is linear with the saturation vapour pressure reduction of air, and be as follows with equation expression:

(Tc-Ta)n＝A+B.VPD (1-3)

Tc crop canopies temperature in the formula (℃), the Ta air themperature (℃), A, B linear regression coeffficient; VPD saturation of the air steam pressure reduction (Pa) water-vapo(u)r saturation is poor, and (Tc-Ta) canopy-air temperature difference of n crop under the potential transpiration state is the lower limit (following baseline) of canopy-air temperature difference.Thereby CWSI is as follows in definition:

$\mathrm{CWSI}=\frac{(\mathrm{Tc}-\mathrm{Ta})-(\mathrm{Tc}-\mathrm{Ta})n}{(\mathrm{Tc}-\mathrm{Ta})u-(\mathrm{Tc}-\mathrm{Ta})n}---(1-4)$

The crop canopy-air temperature difference of (Tc-Ta) actual measurement in the formula; (Tc-Ta) canopy-air temperature difference of u crop under no rising state is the upper limit (going up baseline) of canopy-air temperature difference, and Idso thinks that this is only relevant with an air themperature value, can be calculated by following formula:

(Tc-Ta)u＝A+B.VPG (1-5)

Poor between saturation of the air vapour pressure when saturation of the air vapour pressure when VPG refers to that temperature is Ta in the formula and temperature are Ta+A, A, B are identical with formula (1-1).

2, theoretical pattern: for theoretical pattern, (1988) such as Jackson R D according to the energy balance resistance mode, the upper and lower limit equation of derivation leafing temperature difference:

$(\mathrm{Tc}-\mathrm{Ta})u=\frac{r_a(R_n-G)}{\mathrm{\ρ}{C}_p}\·\frac{\mathrm{\γ}(1+r_{\mathrm{cp}}/r_a)}{\mathrm{\Δ}+\mathrm{\γ}(1+r_{\mathrm{cp}}/r_a)}-\frac{\mathrm{VPD}}{\mathrm{\Δ}+\mathrm{\γ}(1+r_{\mathrm{cp}}/r_a)}---(1-6)$

$(\mathrm{Tc}-\mathrm{Ta})n=\frac{r_a(R_n-G)}{\mathrm{\ρ}{C}_p}---(1-7)$

R in the formula _nCanopy net radiation (W/m ²); Flux density (the W/m of G soil heat flux density or canopy below energy ²); ρ atmospheric density (kg/m ³); C _pAir specific heat (J/ (kg. ℃)); γ psychrometer constant (Pa/ ℃); The temperature variant slope of Δ saturation of the air vapour pressure (Pa/ ℃); r _aAerodynamic drag (s/m); r _CpThe minimum canopy resistance (s/m) of canopy under the potential evaporation state.From the formula of empirical mode and theoretical pattern, empirical equation is comparatively simple, and the meteorologic factor of its consideration is VPD only, and does not consider the influence of other meteorologic factor; The theoretical foundation of theoretical pattern is strengthened, but applied parameter is more in the formula, and some CALCULATION OF PARAMETERS is difficult to obtain result accurately, is difficult to extensive use.The purpose of CWSI is to show the crop water degree that wanes, and is the numerical quantities that is between 0 and 1.Yet the situation greater than 1 appears in employing empirical equation calculating CWSI sometimes, obviously has the irrational situation of result of calculation.Al-Faraj, A. etc. (2000) fuzzy logic algorithm has carried out dynamic decision according to canopy surface temperature, net radiation and steam pressure reduction etc. to the water deficit index CWSI of fescue; Li Guochen (2005) with canopy-air temperature difference Tc-Ta (℃) with relevant environmental factor: saturation of the air steam pressure reduction VPD (kPa), intensity of illumination Rn (W/m ²), wind speed Vw (m/s) is input variable, with CWSI is target output, adopts fuzzy-neural network method, is research object with the cucumber that grows in the Jilin University greenhouse, cucumber water deficit index CWSI in the greenhouse is carried out the dynamic decision analysis, and CWSI result is the zone of reasonableness between 0 and 1 all.0～1 unreasonable situation occurs exceeding though the fuzzy logic algorithm can be eliminated CWSI, the problem that exists also is conspicuous.1, the weighing factor of stipulating each factor of influence that the fuzzification process very important person is, experience has accounted for quite great proportion; 2, need the number of parameters and the theoretical pattern of actual measurement very nearly the same, parameter is still more, and advantage is also not obvious.

Summary of the invention:

The purpose of this invention is to provide a kind of multi-parameter troublesome calculation that need not, do not detect individual difference, non-contact detecting, control is irrigated according to crop water shortage degree method and the device thereof that are easy in the production realize.

The object of the present invention is achieved like this:

A kind of method that control is irrigated according to crop water shortage degree is characterized in that:

At first, place and detect crop environment facies place together with not producing rising reference crop, reference crop level one word is arranged, end in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level, reference crop top ultrasonic emitting head and reference crop top ultrasonic reception head are installed successively, ultrasonic receives the dead ahead of head along reference crop level one word arranged direction above ultrasonic emitting head and reference crop above the reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate is installed; Be positioned at detect crop directly over be equipped with successively to detect crop top ultrasonic emitting head and detect crop top ultrasonic and receive head perpendicular to detecting crop contour cultivation direction level, ultrasonic receives head along the dead ahead of detecting crop contour cultivation direction above detecting above the crop ultrasonic emitting head and detecting crop, be positioned at detect crop directly over be equipped with and detect crop top ultrasonic reflections plate perpendicular to detecting crop contour cultivation direction; Detect crop top ultrasonic emitting head and detect crop top ultrasonic and receive head and receive head distance of ultrasonic reflections plate above the reference crop to the distance that detects crop top ultrasonic reflections plate and reference crop top ultrasonic emitting head and reference crop top ultrasonic and equate;

Secondly, determine window detection time by illumination threshold test module and illumination integral threshold detection module, after reaching the threshold value that sets when illumination, illumination threshold test module starts illumination integral threshold detection module intensity of illumination is carried out integration, after reaching the illumination integral threshold that sets, enter window detection time, be lower than the threshold value that sets when illumination after, the output of illumination threshold test module resets the integrated value zero clearing of illumination integral threshold detection module, withdraws from window detection time;

The 3rd, after entering window detection time, ultrasonic transmission interval control module is activated, produce one group of ultrasonic pulse string by time interval control supersonic generator, this train of pulse is divided into two-way, lead up to reference crop top ultrasonic emitting head, another road is by detecting crop top ultrasonic emitting head, send simultaneously, after reference crop top ultrasonic reception head is received the ultrasonic that is reflected by reference crop top ultrasonic reflections plate, confirm the time point that ultrasonic arrives, confirming enabling counting on the time point that ultrasonic arrives, the rolling counters forward of display module, after ultrasonic reception head in detection crop top is received the ultrasonic that the ultrasonic reflections plate reflects above the detected crop, confirm the time point that ultrasonic arrives, confirming to close counting on the time point that ultrasonic arrives, the rolling counters forward of display module;

The 4th, with the count value of the counter of counting, display module with compare by counting preset module predefined count threshold according to ultrasonic transition time crop water shortage index, if the count threshold that the count value of the counter of counting, display module sets less than the counting preset module, crop water shortage has reached the degree that needs irrigation, will start the small amount irrigation system;

The 5th, withdraw from window detection time after, ultrasonic transmission interval control module is closed, except that illumination threshold test module still work, all the other enter resting state to save power consumption.

Described reference crop is horizontally left each rectangle of placing sidewards simulation leaf in gap mutually and is positioned at preceding deep bead, the rear wind-break panels of simulating the leaf both sides along the horizontal direction of simulation leaf one word by a word to be formed.

Described detection time window, reaching the illumination integral threshold is the necessary condition that enters window detection time, cloudy day does not reach the illumination threshold value, the integrated value of illumination integral threshold detection module still is in and is cleared reset mode, even cloudy weather has reached the illumination threshold value sometime, the output of illumination threshold test module has started illumination integral threshold detection module intensity of illumination has been carried out integration, but before reaching the illumination integral threshold sometime, illumination has been lower than the threshold value that sets again, the output of illumination threshold test module will make the integrated value of illumination integral threshold detection module be cleared again to reset, still do not reach the illumination integral threshold, cloudy day and cloudy weather all do not enter window detection time, make the detection time window drop on the noon 12 of fine weather between at 16 o'clock in afternoon by adjustment illumination threshold value and illumination integral threshold.

The described ultrasonic pulse string that sends simultaneously by reference crop top ultrasonic emitting head and detection crop top ultrasonic emitting head, have identical frequency and phase place, include identical pulse number, it is the upper limit that pulse number still is " rhombus " with the ultrasonic pulse string waveform that receives.

The time point that described ultrasonic arrives is to confirm like this: after reference crop top ultrasonic receives head and detects crop top ultrasonic and receives head and receive reference crop top ultrasonic reflections plate respectively and detect the ultrasonic that crop top ultrasonic reflections plate reflects, send into difference amplifier A respectively, difference amplifier B, after difference is amplified, send into gain-controlled amplifier A respectively, gain-controlled amplifier B, after gain control is amplified, send into high Q value bandpass filter A respectively, high Q value bandpass filter B, behind bandpass filtering, send into half-wave rectifier A respectively, half-wave rectifier B carries out halfwave rectifier, after removing half cycle, send into varying index amplifier A respectively, varying index amplifier B, index as a fixed voltage carries out the varying index amplification to this fixed voltage respectively respectively, under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make each peak value of pulse point both sides more precipitous simultaneously, after varying index amplifies, send into thresholding comparison module A respectively, thresholding comparison module B carries out Threshold detection, find out the pulse of amplitude maximum, send into differential and zero passage detection modules A more respectively, differential and zero passage detection module B, carry out differential and zero passage detection, find out amplitude maximum impulse peak point separately, be respectively reference crop top ultrasonic reception head and receive that the time point of the ultrasonic arrival that is reflected by reference crop top ultrasonic reflections plate and detection crop top ultrasonic receive a time point of receiving the ultrasonic arrival that detected crop top ultrasonic reflections plate reflects.

Described ultrasonic transition time crop water shortage index is definition like this, ultrasonic transition time crop water shortage index:

$\mathrm{UltrasonicTOFCWSI}=1-\frac{\mathrm{\Δt}}{\mathrm{\Δ}{t}_P}---(1-8)$

(1-8) Δ t is the ultrasonic transit time difference of actual detection crop canopies top and reference crop canopy top in the formula, Δ t _PBe the ultrasonic transit time difference of potential or maximum detection crop canopies top with reference crop canopy top, Δ t _pThe maximum Δ t value replacement of actual measurement during available abundant supply water, the reference crop canopy refers to the simulation leaf part that reference crop is accepted solar radiation; When crop not during lack of water because of the rising cooling extent maximum that produces of crop plant, the ultrasonic transit time difference Δ t maximum above corresponding with it detection crop canopies top and the reference crop canopy is with Δ t _PIdentical, Ultrasonic TOF CWSI result of calculation is 0, expression detects not lack of water of crop, in like manner, when the complete water stress of crop stops the crop plant transpiration, because of the rising cooling extent minimum that produces of crop plant, the corresponding with it detection crop canopies top and the ultrasonic transit time difference Δ t minimum of reference crop canopy top, Δ t is 0, and Ultrasonic TOF CWSI result of calculation is 1, and expression detection crop stops transpiration and is in complete water stress state, Ultrasonic TOF CWSI is the indication crop water degree that wanes, be in the numerical quantities between 0 and 1, the big more expression crop water shortage degree of numerical value is high more

The count value of the counter of described counting, display module is " the ultrasonic transit time difference Δ t of actual detection crop canopies top and reference crop canopy top " in the ultrasonic transition time crop water shortage formula of index (1-8), the potential or maximum detection crop canopies top in the formula (1-8) and the ultrasonic transit time difference Δ t of reference crop canopy top _P, fully invade profit with irrigating the back root soil, crop is supplied water, and the maximum Δ t value of actual measurement replaces when sufficient, irrigates for small amount, and counted in the 4th day afternoon 14 o'clock the back with irrigating, the count value of the counter of display module;

The predefined count threshold of described counting preset module is to determine like this, at first, according to the susceptibility of kind plant to arid, ultrasonic transition time crop water shortage index Ultrasonic TOF CWSI when determining to need to irrigate, then, get the last time small amount and irrigate the count value of the counter of the 4th day afternoon 14 o'clock countings in back, display module, as Δ t _P, with Ultrasonic TOF CWSI and Δ t _PSubstitution formula (1-8), that is:

The Δ t of count threshold=(1-UltrasonicTOFCWSI) _P

A kind of device that control is irrigated according to crop water shortage degree, it is characterized in that: will can not produce rising reference crop and place and detect crop environment facies place together, reference crop level one word is arranged, end in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level, reference crop top ultrasonic emitting head and reference crop top ultrasonic is installed successively receives head; Ultrasonic receives the dead ahead of head along reference crop level one word arranged direction above ultrasonic emitting head and reference crop above the reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate is installed; Be positioned at detect crop directly over be equipped with successively to detect crop top ultrasonic emitting head and detect crop top ultrasonic and receive head perpendicular to detecting crop contour cultivation direction level, ultrasonic receives head along the dead ahead of detecting crop contour cultivation direction above detecting above the crop ultrasonic emitting head and detecting crop, be positioned at detect crop directly over be equipped with and detect crop top ultrasonic reflections plate perpendicular to detecting crop contour cultivation direction; Detect crop top ultrasonic emitting head and detect crop top ultrasonic and receive head and receive head distance of ultrasonic reflections plate above the reference crop to the distance that detects crop top ultrasonic reflections plate and reference crop top ultrasonic emitting head and reference crop top ultrasonic and equate;

Control device comprises following each several part: illumination threshold test module, illumination integral threshold detection module, ultrasonic transmission interval control module, counting opens and closes control module, the counting oscillator, the control of ultrasonic pulse number is provided with module, supersonic generator, counting, display module, the counting preset module, count value and count threshold comparison module, comparative result time-delay sampling and maintenance module, small amount irrigation system; Ultrasonic transmits and receives the two-way that part is divided into symmetrical structure, one the tunnel is relevant with reference crop, and they are ultrasonic emitting head high voltage difference driver module A, reference crop top ultrasonic emitting head, reference crop top ultrasonic receives head, difference amplifier A, gain-controlled amplifier A, high Q value bandpass filter A, half-wave rectifier A, varying index amplifier A, thresholding comparison module A, differential and zero passage detection modules A, another road is relevant with the detection crop, they are ultrasonic emitting head high voltage difference driver module B, detect crop top ultrasonic emitting head, detect crop top ultrasonic and receive head, difference amplifier B, gain-controlled amplifier B, high Q value bandpass filter B, half-wave rectifier B, varying index amplifier B, thresholding comparison module B, differential and zero passage detection module B

The control device each several part connects as follows: illumination threshold test module output is connected with illumination integral threshold detection module; Illumination integral threshold detection module output is connected with keeping module with comparative result time-delay sampling with ultrasonic transmission interval control module respectively; Ultrasonic transmission interval control module output opens and closes the control of control module and ultrasonic pulse number with counting respectively and module is set is connected; Counting opens and closes control module with oscillator output end and counting and is connected; Counting opens and closes the control module output and is connected with keeping module with counting, display module and comparative result time-delay sampling respectively; Counting, display module output are connected with the count threshold comparison module with count value; Counting preset module output is connected with the count threshold comparison module with count value; Count value is connected with keeping module with comparative result time-delay sampling with count threshold comparison module output; Comparative result time-delay sampling is connected with the small amount irrigation system with keeping the module output; The control of ultrasonic pulse number is provided with the module output and is connected with supersonic generator; The output of supersonic generator is divided into two-way, be symmetrical structure, one the tunnel through the reference crop top, the rolling counters forward that is used for enabling counting, display module, another road is through detecting the crop top, be used to close the counting of counting, display module, reference crop: the supersonic generator output is connected with ultrasonic emitting head high voltage difference driver module A; Ultrasonic emitting head high voltage difference driver module A output is connected with reference crop top ultrasonic emitting head; Reference crop top ultrasonic receives an output and is connected with difference amplifier A; Difference amplifier A output is connected with gain-controlled amplifier A; Gain-controlled amplifier A output is connected with high Q value bandpass filter A; High Q value bandpass filter A output is connected with half-wave rectifier A; Half-wave rectifier A output is connected with varying index amplifier A; Varying index amplifier A output is connected with thresholding comparison module A; Thresholding comparison module A output is connected with the zero passage detection modules A with differential; Differential opens and closes control module with zero passage detection modules A output with counting and is connected, and is used for the rolling counters forward of enabling counting, display module, and detect crop: the supersonic generator output is connected with ultrasonic emitting head high voltage difference driver module B; Ultrasonic emitting head high voltage difference driver module B output is connected with detection crop top ultrasonic emitting head; Detecting a crop top ultrasonic reception output is connected with difference amplifier B; Difference amplifier B output is connected with gain-controlled amplifier B; Gain-controlled amplifier B output is connected with high Q value bandpass filter B; High Q value bandpass filter B output is connected with half-wave rectifier B; Half-wave rectifier B output is connected with varying index amplifier B; Varying index amplifier B output is connected with thresholding comparison module B; Thresholding comparison module B output is connected with zero passage detection module B with differential; Differential opens and closes control module with zero passage detection module B output with counting and is connected, and is used to close the rolling counters forward of counting, display module.

Described reference crop is horizontally left each rectangle of placing sidewards simulation leaf in gap mutually and is positioned at preceding deep bead, the rear wind-break panels of simulating the leaf both sides along the horizontal direction of simulation leaf one word by a word to be formed.

Details are as follows at the beneficial effect of the technical problem the technical solution adopted in the present invention that exists:

Domestic and international research person is in based on canopy surface temperature method research crop water shortage Study of indexes at present, and the consistent reference of admitting temperature as the crop canopies temperature is almost had no talent its reasonability generation is queried.In fact temperature is also unreasonable as the reference of crop canopies temperature, is mainly reflected in the following aspects:

1, canopy surface temperature is asynchronous with the atmospheric temperature temperature rise, and maximum does not overlap on time point, has bimodal phenomenon.Therefore, there is not unified best observation time point.Observe according to Lv Chuangen (2008), at fine day, daytime, 6:00～13:00 plant temperature (adopting the pin type thermocouple sensor to insert in the leaf sheath) was than air themperature (screen temperature) 1h rising in advance, and day the highest plant temperature appears at 13:00.Air themperature always raises than the late 1h of plant temperature, and daily maximum temperature appears at 14:00.Both are time phase difference 1h not only, and intensity also is that plant temperature is than air themperature height.Lv Chuangen (2008) thinks: cause daytime plant temperature with the air themperature position mutually with the reason of strength difference, be since plant to the absorption ratio of sun shortwave radiation much larger than air.After plant absorbed the solar radiation intensification, the long wave radiation circumference air of release raise the air layer temperature by turbulent flow.After the 13:00, along with weakening of solar radiation, plant temperature descends, and this moment, air themperature was still kept higher level, thereby plant temperature is lower than air themperature.So, be understood that why generally to recommend the best observation time of canopy-air temperature difference be 13:00 or 14:00 rather than at the same time in existing research.

2, reacting condition such as canopy surface temperature and atmospheric temperature, wind speed poor to the essential environmental factors solar radiation, the saturation of the air that influence both gradient of temperatures is inconsistent, and the notable difference on life period and the intensity makes the comparativity variation, uncertain increasing.Cause CWSI canopy-air temperature difference Tc-Ta (℃) baseline up and down need the environmental factor outside the temperature to calculate in addition, not only loaded down with trivial details, and poor accuracy, can cause CWSI 0～1 unreasonable situation to occur exceeding.

3, there be inconsistent (temperature is to monitor with infrared thermometer) on means and the method in canopy surface temperature and atmospheric temperature temperature observation, have also produced suitable uncertainty.

4, it is very difficult in fact accurately to measure temperature, and distinct methods, position and temperature difference that environment is surveyed are very big, do not have unified standard.

Based on above analysis, the present invention proposes the method that can overcome above-mentioned defective in theory, it is achieved in that

At first, will apply glue conduct with reference to crop with detecting the position that may produce transpiration on the crop environment facies crop plant together, making reference crop and the unique difference that detects crop is exactly that reference crop does not have transpiration.Then, copy crop water of formula (1-2) definition and coerce index CWSI (Crop Water StressIndex)

$\mathrm{CWSI}=1-\frac{\mathrm{\ΔT}}{\mathrm{\Δ}{T}_P}---(1-9)$

(1-9) in the formula Δ T be actual reference crop canopy with the temperature difference that detects crop canopies (℃); Δ T _PFor reference crop canopy that may (potential or maximum) and the temperature difference that detects crop canopies (℃), Δ T _PThe maximum Δ T value replacement of actual measurement during available abundant supply water.

With infra-red thermometer witness mark crop canopies and detect the temperature of crop canopies and difference substitution (1-9) formula is calculated CWSI simultaneously, the cooling extent maximum Δ T and the Δ T that do not produce because of crop plant is rising during lack of water when crop _PIdentical, CWSI result of calculation is 0, and expression detects not lack of water of crop.In like manner, when crop lack of water (water stress fully) when the crop plant transpiration is stopped extremely, the rising cooling extent minimum delta T that produces is 0 because of crop plant, and CWSI result of calculation is 1, and expression detection crop stops transpiration and is in extremely lack of water (water stress fully) state.Therefore, CWSI can show the crop water degree that wanes, and is the numerical quantities that is between 0 and 1, and the big more expression crop water shortage degree of numerical value is high more.

Because reference crop is highly consistent except that the plant transpiration with the canopy surface temperature jacking conditions that detects crop,, discharged other such environmental effects so both difference variation are only relevant with the plant transpiration.(1-9) formula has directly reflected the rising ability of plant, has identical result of calculation with (1-2) formula of the rising ability of same reflection plant, can be used as the efficiency index that the indication crop water is coerced fully.

If reference crop canopy and limiting value substitution (1-4) formula that detects the crop canopies temperature difference can be obtained (1-9) formula equally, confirmed the reasonability of this method.

$\mathrm{CWSI}=\frac{(\mathrm{Tc}-\mathrm{Ta})-(\mathrm{Tc}-\mathrm{Ta})n}{(\mathrm{Tc}-\mathrm{Ta})u-(\mathrm{Tc}-\mathrm{Ta})n}=\frac{-\mathrm{\ΔT}-(-\mathrm{\Δ}{T}_P)}{0-(-\mathrm{\Δ}{T}_P)}=1-\frac{\mathrm{\ΔT}}{\mathrm{\Δ}{T}_P}$

In addition, Qiu Guoyu (2004), Wang Liming (2005) tests confirmation, with being coated with last layer glue to block pore, make it no longer to produce transpiration and make the simulation blade, its observed temperature does not have the canopy surface temperature height under the rising situation consistent with the crop that environmental factors such as considering the canopy net radiation is calculated fully.The temperature difference that has confirmed reference crop canopy and detection crop canopies from the another one angle can be got rid of Effect of Environmental such as solar radiation, only with the rising relevant conclusion of plant.

In sum, the most important contribution of this method is: need not to adopt other factor extra computation not have the rising last baseline and the following baseline of potential transpiration, in formula (1-9), Δ T=0 is last baseline, Δ T _PBe following baseline.Make calculating of CWSI with maximum abbreviation.Proposing the purpose of said method, is in order to allow the reader can better understand inventor's final invention.This method has fundamentally been got rid of real-time monitoring plant Effect of Environmental such as solar radiation when rising, only needs a kind of parameter of temperature, just can accurately detect the rising situation of crop plant.Secondly both temperature of reference crop and detection crop canopies (blade) can have been eliminated the uncertainty of temperature observation means and the inconsistent generation of method simultaneously with the infrared thermometer monitoring.But this method still has following deficiency: 1, adopting the method making reference crop of true crop plant spreading glue is unpractical on producing; 2, investment significantly increases.In actual applications, because the detection visual angle of infrared thermometer is very little, in order to reduce Spatial Variability (detection individual difference), non-moving infrared thermometry mode generally needs 3 of infrared thermometers arranged apart, averages as observed result.In order to keep the observation method advantage consistent with method, reference crop also needs to use the infrared thermometer thermometric, therefore, infrared thermometer to be increased to 4 or more than.For overcoming above deficiency, the present invention has adopted following technical scheme.

1, substituted the reference crop of making of the method for true crop plant spreading glue with the artificial reference crop of being convenient to produce.Qiu Guoyu (2004), Wang Liming (2005) tests confirmation, adopts paper with the same color of blade to be cut into the simulation blade that blade shape makes and can substitute the simulation blade made from true crop plant blade spreading glue fully.

2, adopted the ultrasonic transition time the non-contacting mean temperature of measuring many crop plants simultaneously of (time-of-flight is called for short ToF) environment temperature measuring method, both saved investment, there has not been the detection individual difference again, especially custom is planted in the row sowing that is fit to crop, effectively reduced the influence of bare soil to observed result, advantage is conspicuous.

The aerial spread speed of sound wave can be calculated by following formula

$v=\sqrt{\frac{\mathrm{\γ}\·R\·T}{M}}---(1-10)$

γ is that pressurization by compressed air specific heat capacity and specific heat at constant volume are than (γ=C in the formula _P/ C _V); R is the gas universal constant; M is a molecular weight gas; T is an absolute temperature.

By formula (1-10) as seen, temperature is the principal element that influences THE VELOCITY OF SOUND IN AIR.

At 0 ℃ of (T ₀=velocity of sound 273.15K) time

${\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="HSA00000016192200051.png,HSA00000016192200081.png"\; state="\{\{state\}\}">v</figure-callout>}}_0=\sqrt{\frac{\mathrm{\&gamma;}\&CenterDot;R\&CenterDot;T_0}{M}}=331.45M/S---(1-11)$

The velocity of sound (M/S) in the time of t ℃

$v_t=v_0\sqrt{(1+\frac{t}{273.15})}\&ap;331.4+0.607t---(1-12)$

By formula (1-12) as can be seen, the velocity of sound is the function of sonic transmissions medium air mean temperature, under the known situation of sonic transmissions distance, just can calculate the velocity of sound as long as detect the sound wave transition time, and then calculate the mean temperature of sonic transmissions medium air.

Obtained practical application with this method measures ambient temperature.For example: U.S. SEI company --the sound wave gas temperature field measuring system just success be used to measure furnace temperature; Taiwan Gao Yuan skill Intraoperative Learn institute etc. has studied the environmental temperature of measuring in the car with this method and has been used for air-conditioning or the like in the car.

In the present invention, save the software and hardware input and be easy to realization in order to reduce amount of calculation, there are not the Practical Calculation temperature and the temperature difference, but the principle of (1-9) formula of imitation, directly define a ultrasonic transition time crop water and coerced index (Crop Water Stress Index on Ultrasonic time-of-flight is called for short Ultrasonic TOF CWSI, is also referred to as ultrasonic transition time crop water shortage index among the present invention)

$\mathrm{UltrasonicTOFCWSI}=1-\frac{\mathrm{\&Delta;t}}{\mathrm{\&Delta;}{t}_P}---(1-8)$

(1-8) Δ t is the ultrasonic transit time difference of actual detection crop canopies top and reference crop canopy top in the formula; Δ t _PBe the detection crop canopies top of possible (potential or maximum) and the ultrasonic transit time difference above the reference crop canopy, Δ t _PThe maximum Δ t value replacement of actual measurement during available abundant supply water.(annotate: said reference crop canopy refers to the simulation leaf part that reference crop is accepted solar radiation among the present invention).When crop not during lack of water because of the rising cooling extent maximum that produces of crop plant, the ultrasonic transit time difference Δ t maximum above corresponding with it detection crop canopies top and the reference crop canopy is with Δ t _PIdentical, UltrasonicTOF CWSI result of calculation is 0, and expression detects not lack of water of crop.In like manner, when crop lack of water (water stress fully) when the crop plant transpiration is stopped extremely, because of the rising cooling extent minimum that produces of crop plant, the corresponding with it detection crop canopies top and the ultrasonic transit time difference Δ t minimum of reference crop canopy top, Δ t is 0, Ultrasonic TOF CWSI result of calculation is 1, and expression detection crop stops transpiration and is in extremely lack of water (water stress fully) state.Therefore, Ultrasonic TOF CWSI can show the crop water degree that wanes, and is the numerical quantities that is between 0 and 1, and the big more expression crop water shortage degree of numerical value is high more.

In the present invention, ultrasonic measurement be reference crop and detect crop thermal radiation heating canopy top air after environmental temperature, though can not the same direct witness mark crop and detect the temperature of crop canopies itself with infrared thermometer, if but reference crop is consistent with the testing conditions that detects crop canopies, even the temperature difference of both canopies that the absolute value of both Canopy Environment temperature difference records less than infrared thermometer own, do not influence the result of calculation of (1-8) formula yet, because what (1-8) formula was calculated is the ratio (result is dimensionless number, and is identical with ratio (1-9) the formula effect of reference crop and detection crop canopies temperature relative value) of same amount relative value.

The absolute value that detects the circumstance of temperature difference of crop canopies top and reference crop canopy top is far smaller than the own temperature difference of both canopies that infrared thermometer records, and therefore resolution and the precision to the ultrasonic thermometric had higher requirement.

The precision of ultrasonic measurement environmental temperature depends primarily on the accurate detection ultrasonic transition time, accurately detects the ultrasonic transition time to depend on the time point of judging that exactly ultrasonic arrives.As shown in Figure 1, in ultrasonic transducer power conversion and sound wave air transfer process, because the existence of mechanical elasticity (elasticity of ultrasonic transducer piezoelectric ceramic piece and air), can produce ultrasonic waveform amplitude fading at the head and the afterbody of the ultrasonic pulse string that receives.There is the composition of change at random in intensity (amplitude) when ultrasonic arrives, and the time point that adopts conventional strength threshold (threshold is also referred to as threshold or threshold value) method to judge that ultrasonic arrives is inaccurate, can not detect the ultrasonic transition time exactly.Generally only be used for less demanding occasions such as robot obstacle-avoiding, reversing anticollision device, collision-prevention device.

For the time point of judging that exactly ultrasonic arrives, people have carried out a lot of improvement, use more have 3 kinds.

1, phase difference (phase-shift) method.This method short-range applications is very accurate, has been widely used in the ultrasonic wind speed instrument, the atmosphere thermometric of automatic weather station etc.Temperature measurement accuracy is up to ± 0.05 ℃.But this method can only be used for the very short occasion of ultrasonic transmission distance, for example 10cm.Obviously can not be used for the present invention.

2, modulation waveform tracer method.To sound wave modulate, coding, spread spectrum etc. all belong to this type of.Using more is double frequency frequency shift keying (binary frequency shift-keyed is called for short BFSK) method, has been used for sedan air conditioner thermometric and ultrasonic range finder.Temperature measurement accuracy ± 0.4 ℃.Taiwan Cai Wen unit of Gao Yuan University of Science and Technology combines this method and phase difference method, make temperature measurement accuracy bring up to ± 0.3 ℃, still can not satisfy requirement of the present invention.

3, train of pulse envelope (envelope pulsed) Peak Intensity Method.Train of pulse envelope center of gravity abscissa method in addition similarly.Requirement of the present invention still can not be satisfied in temperature measurement accuracy ± 0.39 ℃.

Very unfortunate, existing ultrasonic temp measuring method can not meet the demands.In order to realize the present invention, the detection method of remote ultrasonic transition time more accurately must be arranged.For this reason, invented the detection method of a kind of new ultrasonic transition time, relevant introduction in detail please see that the other patent of invention that the present invention first inventor applies for simultaneously " detects method and the device thereof of ultrasonic transition time ".

Existing document general recommendations is placed on noon 12 to window detection time of CWSI between at 16 o'clock in afternoon, and rejects cloudy day and cloudy weather, and optimum observation time is afternoon 13 o'clock or 14 o'clock, and existing document is confined to the manual operations of research aspect substantially.Also do not see the concrete method of determining window detection time automatically.Proposed one in the present invention and rejected the cloudy day, rejected the new technical scheme of determining window detection time automatically of cloudy weather with the illumination integral threshold with the illumination threshold value.

Operation principle of the present invention and control irrigation process are such:

Illumination threshold test part is in running order all the time, and ultrasonic emission and charactron display part that power consumption is bigger are in resting state.At fine weather, rise along with the sun, illumination progressively strengthens, after reaching the illumination threshold value that sets, start the illumination integral part intensity of illumination is carried out integration, after reaching the illumination integral threshold that sets, enter window detection time, control device is waken up from resting state, by the time interval of setting respectively in the top that gets close to reference crop (not producing rising simulation crop) and detection crop, be parallel to plane, crop place, below separately, simultaneously to the equidistant ultrasonic reflections plate emission ultrasonic in dead ahead separately that is positioned at, after receiving the ultrasonic that reflects separately, start and stop same rolling counters forward respectively, count value and the count threshold of setting according to ultrasonic transition time crop water shortage index are compared, if count value is less than the count threshold that sets, crop water shortage has reached the degree that needs irrigation, will start irrigation.Along with sun landing, illumination progressively weakens, and after being lower than the illumination threshold value that sets, the illumination integrated value is cleared, and withdraws from window detection time, and control device reenters resting state.Do not reach the illumination threshold value when the cloudy day, cloudy weather does not reach the illumination integral threshold, can not enter window detection time, and control device still is in resting state and can change.

The present invention at first has been divided into control device and need have worked but power consumption less (illumination detection) and do not need often work but two parts of power consumption big (ultrasonic emission and charactron demonstration etc.) always, usually make the bigger part of power consumption be in resting state, be waken up again when needing work, to save power consumption.Illumination threshold test part and illumination integral threshold test section are used for definite automatically detection time of window.When the radiation activity of the sun is not enough or cloudy, illumination will not reach set threshold value, and control device is in resting state all the time; If cloudy weather, even reached the illumination threshold value sometime, started the illumination integration but the illumination integrated value does not reach the illumination integral threshold that sets, control device still is in resting state; If fine weather, along with the rise of the sun, illumination progressively strengthens, after reaching the illumination threshold value that sets, start the illumination integral part intensity of illumination is carried out integration, after reaching the illumination integral threshold that sets, enter window detection time, control device is waken up from resting state.Thereby rejected cloudy day and cloudy weather, can make the detection time window drop on the noon 12 of fine weather between at 16 o'clock in afternoon by adjusting illumination threshold value and illumination integral threshold.After control device is waken up from resting state, by the time interval of setting respectively in the top that gets close to reference crop (not producing rising simulation crop) and detection crop, be parallel to plane, crop place, below separately, simultaneously to the equidistant ultrasonic reflections plate emission ultrasonic in dead ahead separately that is positioned at, after receiving the ultrasonic that reflects separately, start and stop same rolling counters forward respectively, count value and the count threshold that sets are compared, if count value less than the count threshold that sets, will start irrigation.The count value here is exactly that ultrasonic transition time crop water is coerced the ultrasonic transit time difference Δ t of reference crop canopy top " the actual detection crop canopies top with " in the index computing formula (1-8)." the detection crop canopies top of possibility (potential or maximum) and the ultrasonic transit time difference Δ t of reference crop canopy top in the formula (1-8) _P", available irrigation back root soil is fully invaded profit, and the maximum Δ t value of actual measurement replaced when crop was supplied water abundance, irrigated for small amount, the 4th day (overcast and rainy cloudy weather is postponed) the afternoon 14 o'clock count value in available irrigation back.Generally speaking, available above-mentioned Δ t _P80%～60% of count value, determine the count threshold of irrigation time point, behind both substitution formula (1-8), it is 0.2～0.4 that calculating ultrasonic transition time crop water is coerced index (lack of water index), and concrete numerical value can be determined the susceptibility of arid according to the kind plant.Certainly, behind the available crop wilting point actual measurement count threshold bottom line, determine further that by the crop water production efficiency and the situation that can supply water except that scientific research, actual irrigation does not recommend need not do like that yet again.Starting irrigation with the crop water shortage index greater than 0.4 o'clock is example, situation when a common peasant irrigates with device control of the present invention: after this device installs, the bits per inch word that at first count threshold of this device is preset digital toggle switch all pushes 0, manually carrying out small amount then irrigates, the count value of checking the demonstration of this device charactron at the 4th day afternoon 14 o'clock after irrigating, after this count value be multiply by 0.6, preset with digital toggle switch with the count threshold of this device and be input to this device, this device has been in automatic control state.After reaching the illumination threshold value that sets when illumination, start the illumination integral part intensity of illumination is carried out integration, after reaching the illumination integral threshold that sets, enter window detection time, control device is waken up from resting state.Carry out the crop water shortage index and detect, if the crop water shortage index is that count value is less than count threshold, with regard to the startup irrigation greater than 0.4.After being lower than the illumination threshold value that sets when illumination, withdraw from window detection time, control device reenters resting state, waits for that entering next detection time is waken up during window.If irrigate, the count value of checking the demonstration of this device charactron at the 4th day afternoon 14 o'clock after irrigating, this count value be multiply by 0.6 after, preset digital toggle switch with the count threshold of this device again and be input to this device.The rest may be inferred has finished and has controlled the irrigation process whole crop growing season.

As mentioned above, when this device enters window detection time, control device is waken up from resting state, the ultrasonic timed sending is activated, respectively get close to reference crop and detect crop above, be parallel to plane, crop place and simultaneously be positioned at separately to equidistant that the ultrasonic reflections plate emission in dead ahead has the identical pulse number, produce and ultrasonic pulse string that have identical frequency and phase place by same supersonic generator.Frequency is identical with phase place when having only emission, and the two-way ultrasonic pulse string maximum impulse peak point of receiving is the tool comparativity.Ultrasonic has adopted the straight line reciprocating manner in air be in order to get rid of the influence of wind.The pulse number that train of pulse comprised is set in advance by this device ultrasonic pulse number toggle switch, set number and depend on ultrasonic transducer piezoelectric ceramic piece elasticity and ultrasonic (mechanical energy ripple) transmission range, to form " rhombus " received pulse string waveform is that (pulse number is set before handing over the user to use principle, need not the user and changes.)。After reference crop and the ultrasonic that detects the crop top receive head, receive the ultrasonic that the ultrasonic reflections plate reflects separately respectively, after difference amplifier is amplified to certain amplitude separately, send into gain-controlled amplifier separately respectively respectively.The purpose that difference is amplified is to reduce common-mode noise to improve signal to noise ratio.Respectively after gain-controlled amplifier amplifies separately, send into high separately Q value bandpass filter respectively, carry out height " Q " value filtering and slightly amplification, purpose is the amplitude of wave form of filtering out-of-band noise and compression distortion part, helps formation " rhombus " received pulse string waveform.Then, carry out halfwave rectifier respectively, remove behind the half cycle, send into varying index amplifier separately respectively, this fixed voltage is carried out varying index amplify as the index of a fixed voltage.The purpose that varying index amplifies, be under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make peak value of pulse point both sides more precipitous simultaneously, the pulse of convenient identification amplitude maximum and the accurate position of peak point thereof.Sending into separately then respectively, the thresholding comparison module carries out the pulse that Threshold detection is found out the amplitude maximum respectively.Respectively it is carried out differential and zero passage detection again, find out amplitude maximum impulse peak point respectively, be respectively applied for startup and close same rolling counters forward.The present invention has adopted the mode of deciding the thresholding control gain to find out the pulse of amplitude maximum.Behind the emission ultrasonic, counter does not enter duty, but has passed through suitable time-delay, and purpose is that the ultrasonic of avoiding emitting head to reveal directly enters a reception improper enabling counting device at once.Realized the detection of accurate ultrasonic transition time with said method, solved and concerned key of success technical problem of the present invention.

Prototype of the present invention is according to the specially designed cheap type that helps applying of China's actual conditions, all drop into, even be lower than the price of the special-purpose crop canopies infrared temperature-test sensor (as: the special-purpose crop canopies Hong Waicewenchuanganqi of Apogee $598) of an import less than 3000$.In micro-processor controlled luxurious type, can realize comprising Δ t _PAutomatically gather input automatically at interior whole automatic operatings, running parameter can be by mouse, keyboard input, and result's (comprising historical datas such as operation curve) can show inquiry at computer desktop.

Δ t _PAdopted the measured value after each irrigation, not only value is convenient, the more important thing is the Δ t that has considered under Different Crop, various seasons, the different coverage condition _PVariation.Adopt the small amount irrigation method, help to increase Δ t _PDetection density, improve Δ t _PThe accuracy of representative and irrigation control accuracy.

Adopt technical scheme of the present invention to compare with traditional infrared C WSI method, have following advantage: 1, this scheme has fundamentally been got rid of real-time monitoring plant Effect of Environmental such as solar radiation when rising, only need a kind of parameter of temperature, just can accurately detect the rising situation of crop plant, need not to adopt other factor (environmental parameter) extra computation not have the rising last baseline and the following baseline of potential transpiration, in Ultrasonic TOF CWSI formula (1-8), Δ t=0 is last baseline, Δ t _PBe following baseline.Therefore, detected parameters is few, does not have troublesome calculation and multiple-factor to detect cumulative error; 2, this scheme directly detects the mean value of many crops, therefore, does not detect individual difference, need not to reduce this species diversity by the value volume and range of product that increases sensor; 3, adopt the temperature sensor (being ultrasonic temperature sensor) of same type, good comparability, data are reliable; 4, the kind of required sensor and minimum number are with low cost, are easy to realize and promote.

Description of drawings:

The ultrasonic pulse string schematic diagram of Fig. 1 for receiving.

Fig. 2 arranges schematic diagram for control device detection probe of the present invention is on-the-spot.

Fig. 3 forms and workflow diagram for control device of the present invention.

Fig. 4,5,6,7,8,9,10,11,12,13,14,15 is an embodiment of the invention circuit diagram.

Embodiment:

As Fig. 2, shown in Figure 3, a kind of method that control is irrigated according to crop water shortage degree:

At first, place and detect crop 46 environment facies place together with not producing rising reference crop, reference crop level one word is arranged, end in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level, reference crop top ultrasonic emitting head 16 and reference crop top ultrasonic is installed successively receives 18, ultrasonic receives 18 dead ahead along reference crop level one word arranged direction above ultrasonic emitting head 16 and reference crop above the reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate 45 is installed, be positioned at detect crop 46 directly over perpendicular to detecting crop 46 contour cultivation direction levels, be equipped with successively to detect crop top ultrasonic emitting head 15 and detect crop top ultrasonic and receive 17, ultrasonic receives 17 dead ahead along detection crop 46 contour cultivation directions above ultrasonic emitting head 15 above the detection crop and detection crop, be positioned at detect crop 46 directly over be equipped with and detect crop top ultrasonic reflections plate 47 perpendicular to detecting crop 46 contour cultivation directions, detect crop top ultrasonic emitting head 15 and detect crop top ultrasonic receive 17 to the distance that detects crop top ultrasonic reflections plate 47 and reference crop top ultrasonic emitting heads 16 and reference crop top ultrasonic receive 18 above the reference crop distances of ultrasonic reflections plate 45 equate.

Described reference crop is horizontally left some rectangle simulation leaves of placing sidewards 42 of appropriate gap mutually and is positioned at the front-and- back stop aerofoil 43,44 of simulating leaf 42 both sides along the horizontal direction of simulation leaf 42 1 words by a word to be formed,

Secondly; Determine window detection time by illumination threshold value detection module 1 and illumination integral threshold detection module 2; After reaching the threshold value that sets when illumination; Illumination threshold value detection module 1 starts 2 pairs of intensities of illumination of illumination integral threshold detection module and carries out integration; After reaching the illumination integral threshold that sets; Enter window detection time; After being lower than the threshold value that sets when illumination; The output of illumination threshold value detection module 1 resets the integrated value zero clearing of illumination integral threshold detection module 2; Withdraw from window detection time

Described detection time window, reaching the illumination integral threshold is the necessary condition that enters window detection time, cloudy day does not reach the illumination threshold value, the integrated value of illumination integral threshold detection module 2 still is in and is cleared reset mode, even cloudy weather has reached the illumination threshold value sometime, the output of illumination threshold test module 1 has started 2 pairs of intensities of illumination of illumination integral threshold detection module and has carried out integration, before reaching the illumination integral threshold sometime, illumination is lower than the threshold value that sets again, the output of illumination threshold test module 1 is cleared the integrated value of illumination integral threshold detection module 2 to reset again, still do not reach the illumination integral threshold, cloudy day and cloudy weather all do not enter window detection time, make the detection time window drop on the noon 12 of fine weather between at 16 o'clock in afternoon by adjusting illumination threshold value and illumination integral threshold

The 3rd, after entering window detection time, ultrasonic transmission interval control module 3 is activated, produce one group of ultrasonic pulse string by certain time interval control supersonic generator 6, this train of pulse is divided into two-way, lead up to reference crop top ultrasonic emitting head 16, another road is by detecting crop top ultrasonic emitting head 15, send simultaneously, when reference crop top ultrasonic receive 18 receive the ultrasonic that is reflected by reference crop top ultrasonic reflections plate 45 after, confirm the time point that ultrasonic arrives, confirming enabling counting on the time point that ultrasonic arrives, the rolling counters forward of display module 8, when detect crop top ultrasonic receive 17 receive the ultrasonic that detected crop top ultrasonic reflections plate 47 reflects after, confirm the time point that ultrasonic arrives, confirming to close counting on the time point that ultrasonic arrives, the rolling counters forward of display module 8

The described ultrasonic pulse string that sends simultaneously by reference crop top ultrasonic emitting head 16 and detection crop top ultrasonic emitting head 15, have identical frequency and phase place, include identical pulse number, it is the upper limit that pulse number still is " rhombus " shown in Figure 1 with the ultrasonic pulse string waveform that receives

The time point that described ultrasonic arrives is to confirm like this: reference crop top ultrasonic receive 18 and detect crop top ultrasonic receive 17 receive reference crop top ultrasonic reflections plate 45 respectively and detect the ultrasonic that crop top ultrasonic reflections plate 47 reflects after, send into difference amplifier A20 respectively, difference amplifier B19 tentatively amplifies, the form that adopts difference to amplify is to improve signal to noise ratio in order better to suppress common-mode noise, after difference is amplified, send into gain-controlled amplifier A22 respectively, gain-controlled amplifier B21 further is amplified to desired amplitude, after gain control is amplified, send into high Q value bandpass filter A24 respectively, high Q value bandpass filter B23 carries out bandpass filtering, filtering band external noise, reduce the signal amplitude that departs from dominant frequency simultaneously, behind bandpass filtering, send into half-wave rectifier A26 respectively, half-wave rectifier B25 carries out halfwave rectifier, after removing half cycle, send into varying index amplifier A28 respectively, varying index amplifier B27, index as a fixed voltage carries out the varying index amplification to this fixed voltage respectively respectively, the purpose that varying index amplifies, be under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make peak value of pulse point both sides more precipitous simultaneously, the pulse of convenient identification amplitude maximum and the accurate position of peak point thereof, after varying index amplifies, send into thresholding comparison module A30 respectively, thresholding comparison module B29 carries out Threshold detection, find out the pulse of amplitude maximum, send into differential and zero passage detection modules A 32 more respectively, differential and zero passage detection module B31, carry out differential and zero passage detection, find out amplitude maximum impulse peak point separately, being respectively reference crop top ultrasonic receives 18 and receives the time point that the ultrasonic that reflected by reference crop top ultrasonic reflections plate 45 arrives and detect crop top ultrasonic and receive 17 and receive the time point that ultrasonic that detected crop top ultrasonic reflections plate 47 reflects arrives

The 4th, with the count value of the counter of counting, display module 8 with compare by counting preset module 9 predefined count threshold according to ultrasonic transition time crop water shortage index, if the count threshold that the count value of the counter of counting, display module 8 sets less than counting preset module 9, crop water shortage has reached the degree that needs irrigation, to start small amount irrigation system 12

Described ultrasonic transition time crop water shortage index is definition like this, and a ultrasonic transition time crop water is coerced index (Crop Water Stress Index on Ultrasonic time-of-flight is called for short Ultrasonic TOF CWSI the present invention and is also referred to as ultrasonic transition time crop water shortage index)

$\mathrm{UltrasonicTOFCWSI}=1-\frac{\mathrm{\&Delta;t}}{\mathrm{\&Delta;}{T}_P}---(1-8)$

(1-8) Δ t is the ultrasonic transit time difference of actual detection crop canopies top and reference crop canopy top in the formula, Δ t _PBe the detection crop canopies top of possible (potential or maximum) and the ultrasonic transit time difference above the reference crop canopy, Δ t _PThe maximum Δ t value replacement of actual measurement during available abundant supply water, the reference crop canopy refers to the simulation leaf part that reference crop is accepted solar radiation,

When crop not during lack of water because of the rising cooling extent maximum that produces of crop plant, the ultrasonic transit time difference Δ t maximum above corresponding with it detection crop canopies top and the reference crop canopy is with Δ t _PIdentical, Ultrasonic TOF CWSI result of calculation is 0, expression detects not lack of water of crop, in like manner, when crop lack of water (water stress fully) when the crop plant transpiration is stopped extremely, because of the rising cooling extent minimum that produces of crop plant, the corresponding with it detection crop canopies top and the ultrasonic transit time difference Δ t minimum of reference crop canopy top, Δ t is 0, and Ultrasonic TOF CWSI result of calculation is 1, and expression detection crop stops transpiration and is in extremely lack of water (water stress fully) state, Ultrasonic TOF CWSI is the indication crop water degree that wanes, be in the numerical quantities between 0 and 1, the big more expression crop water shortage degree of numerical value is high more

The count value of the counter of described counting, display module 8 is exactly that ultrasonic transition time crop water is coerced the ultrasonic transit time difference Δ t of reference crop canopy top " the actual detection crop canopies top with " in the index computing formula (1-8), " the detection crop canopies top that may (potential or maximum) and the ultrasonic transit time difference Δ t of reference crop canopy top in the formula (1-8) _P", available irrigation back root soil is fully invaded profit, crop is supplied water, and the maximum Δ t value of actual measurement replaces when sufficient; irrigates for small amount; after available the irrigation the 4th day (overcast and rainy cloudy weather is postponed) counted in afternoon 14 o'clock, the count value of the counter of display module 8, generally speaking, available above-mentioned Δ t _P80%～60% of count value, determine the count threshold of irrigation time point, behind both substitution formula (1-8), it is 0.2～0.4 that calculating ultrasonic transition time crop water is coerced index (lack of water index), the concrete numerical value of ultrasonic transition time crop water shortage index can be determined the susceptibility of arid according to the kind plant

Described counting preset module 9 predefined count threshold are to determine like this, at first, according to the susceptibility of kind plant to arid, ultrasonic transition time crop water shortage index Ultrasonic TOF CWSI when determining to need to irrigate, then, get the last time small amount and irrigate the count value of the counter of the afternoon 14 o'clock countings in back the 4th day (overcast and rainy cloudy weather is postponed), display module 8, as Δ t _P, with Ultrasonic TOFCWSI and Δ t _PSubstitution formula (1-8), that is:

Count threshold=(1-UltrasonicTOF CWSI) Δ t _P

Δ t _PAdopted the measured value after each irrigation, not only value is convenient, the more important thing is the Δ t that has considered under Different Crop, various seasons, the different coverage condition _PVariation, adopt the small amount irrigation method, help to increase Δ t _PDetection density, improve Δ t _PThe accuracy of representative and irrigation control accuracy,

The 5th, withdraw from window detection time after, ultrasonic transmission interval control module 3 is closed, except that illumination threshold test module 1 still work, all the other enter resting state to save power consumption.

A kind of device that control is irrigated according to crop water shortage degree: the scene of control device detection probe of the present invention is arranged as shown in Figure 2.

Place and detect crop 46 environment facies place together with not producing rising reference crop, reference crop level one word is arranged, end in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level reference crop top ultrasonic emitting head 16 and reference crop top ultrasonic are installed successively and receive 18, ultrasonic receives 18 dead ahead along reference crop level one word arranged direction above ultrasonic emitting head 16 and reference crop above the reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate 45 is installed, be positioned at detect crop 46 directly over be equipped with successively to detect crop top ultrasonic emitting head 15 and detect crop top ultrasonic and receive 17 perpendicular to detecting crop 46 contour cultivation direction levels, ultrasonic receives 17 dead ahead along detection crop 46 contour cultivation directions above ultrasonic emitting head 15 above the detection crop and detection crop, be positioned at detect crop 46 directly over be equipped with and detect crop top ultrasonic reflections plate 47 perpendicular to detecting crop 46 contour cultivation directions, detect crop top ultrasonic emitting head 15 and detect crop top ultrasonic receive 17 to the distance that detects crop top ultrasonic reflections plate 47 and reference crop top ultrasonic emitting heads 16 and reference crop top ultrasonic receive 18 above the reference crop distances of ultrasonic reflections plate 45 equate.

Described reference crop is horizontally left some rectangle simulation leaves of placing sidewards 42 of appropriate gap mutually and is positioned at the front-and- back stop aerofoil 43,44 of simulating leaf 42 both sides along the horizontal direction of simulation leaf 42 1 words by a word to be formed.

Control device each several part of the present invention is formed as shown in Figure 3, illumination threshold test module 1, illumination integral threshold detection module 2, ultrasonic transmission interval control module 3, counting opens, close control module 4, counting oscillator 5, the control of ultrasonic pulse number is provided with module 6, supersonic generator 7, counting, display module 8, counting preset module 9, count value and count threshold comparison module 10, comparative result time-delay sampling and maintenance module 11, small amount irrigation system 12, ultrasonic transmits and receives part and is divided into two-way, be symmetrical structure, one the tunnel is relevant with reference crop, and they are ultrasonic emitting head high voltage difference driver module A14, reference crop top ultrasonic emitting head 16, reference crop top ultrasonic receives 18, difference amplifier A20, gain-controlled amplifier A22, high Q value bandpass filter A24, half-wave rectifier A26, varying index amplifier A28, thresholding comparison module A30, differential and zero passage detection modules A 32; Another road is relevant with the detection crop, they are ultrasonic emitting head high voltage difference driver module B13, detect crop top ultrasonic emitting head 15, detect crop top ultrasonic and receive 17, difference amplifier B19, gain-controlled amplifier B21, high Q value bandpass filter B23, half-wave rectifier B25, varying index amplifier B27, thresholding comparison module B29, differential and zero passage detection module B31

Control device each several part of the present invention connects as shown in Figure 3, and illumination threshold test module 1 output is connected with illumination integral threshold detection module 2; Illumination integral threshold detection module 2 outputs are connected with keeping module 11 with comparative result time-delay sampling with ultrasonic transmission interval control module 3 respectively; Ultrasonic transmission interval control module 3 outputs open and close the control of control module 4 and ultrasonic pulse number with counting respectively and module 6 is set is connected; Counting opens and closes control module 4 with oscillator 5 outputs and counting and is connected; Counting opens and closes control module 4 outputs and is connected with keeping module 11 with counting, display module 8 and comparative result time-delay sampling respectively; Counting, display module 8 outputs are connected with count threshold comparison module 10 with count value; Counting preset module 9 outputs are connected with count threshold comparison module 10 with count value; Count value is connected with keeping module 11 with comparative result time-delay sampling with count threshold comparison module 10 outputs; Comparative result time-delay sampling is connected with small amount irrigation system 12 with keeping module 11 outputs; The control of ultrasonic pulse number is provided with module 6 outputs and is connected with supersonic generator 7; The output of supersonic generator 7 is divided into two-way, be symmetrical structure, one the tunnel through the reference crop top, the rolling counters forward that is used for enabling counting, display module 8, another road is through detecting the crop top, be used to close the rolling counters forward of counting, display module 8, reference crop: supersonic generator 7 outputs are connected with ultrasonic emitting head high voltage difference driver module A14; Ultrasonic emitting head high voltage difference driver module A14 output is connected with reference crop top ultrasonic emitting head 16; Reference crop top ultrasonic receives 18 output and is connected with difference amplifier A20; Difference amplifier A20 output is connected with gain-controlled amplifier A22; Gain-controlled amplifier A22 output is connected with high Q value bandpass filter A24; High Q value bandpass filter A24 output is connected with half-wave rectifier A26; Half-wave rectifier A26 output is connected with varying index amplifier A28; Varying index amplifier A28 output is connected with thresholding comparison module A30; Thresholding comparison module A30 output is connected with zero passage detection modules A 32 with differential; Differential opens and closes control module 4 with zero passage detection modules A 32 outputs and counting and is connected, and is used for the rolling counters forward of enabling counting, display module 8.Detect crop: supersonic generator 7 outputs are connected with ultrasonic emitting head high voltage difference driver module B13; Ultrasonic emitting head high voltage difference driver module B13 output is connected with detection crop top ultrasonic emitting head 15; Detecting crop top ultrasonic reception 17 output is connected with difference amplifier B19; Difference amplifier B19 output is connected with gain-controlled amplifier B21; Gain-controlled amplifier B21 output is connected with high Q value bandpass filter B23; High Q value bandpass filter B23 output is connected with half-wave rectifier B25; Half-wave rectifier B25 output is connected with varying index amplifier B27; Varying index amplifier B27 output is connected with thresholding comparison module B29; Thresholding comparison module B29 output is connected with zero passage detection module B31 with differential; Differential opens and closes control module 4 with zero passage detection B31 output and counting and is connected, and is used to close the rolling counters forward of counting, display module 8,

Control device workflow of the present invention such as Fig. 2, shown in Figure 3, illumination threshold test module 1 is in running order all the time, fine weather, The sun came up, after reaching the threshold value that sets when illumination, illumination threshold test module 1 starts 2 pairs of intensities of illumination of illumination integral threshold detection module and carries out integration, after reaching the illumination integral threshold that sets, enter window detection time, control device is waken up from resting state, the output of illumination integral threshold detection module 2 is divided into two-way, and one the tunnel makes comparative result time-delay sampling remove reset mode with keeping module 11; Another road starts 3 work of ultrasonic transmission interval control module, ultrasonic transmission interval control module 3 is sent enabling signal by the time interval of setting, this enabling signal is divided into two-way, one the tunnel starts the control of ultrasonic pulse number is provided with one group of ultrasonic pulse string of module 6 control supersonic generators, 7 generations, and the pulse number that the ultrasonic pulse string comprises is provided with module 6 by the control of ultrasonic pulse number and preestablishes; Another road is sent into counting and is opened, close control module 4, open at counting, the inside of closing control module 4 by one of the rising edge triggering for generating of this enabling signal broadened reset signal, counting is opened, closing control module 4 resets, the broadening reset signal is directly to enter reference crop top ultrasonic for fear of the ultrasonic that reference crop top ultrasonic emitting head 16 is revealed to receive 18 an improper enabling counting, the rolling counters forward of display module 8 directly enters detection crop top ultrasonic reception 17 an improper counting of closing with the ultrasonic of avoiding detecting ultrasonic emitting head 15 leakages of crop top, the rolling counters forward of display module 8, the ultrasonic pulse string that supersonic generator 7 produces is divided into two-way, be symmetrical structure, one the tunnel through the reference crop top, be used for enabling counting, the rolling counters forward of display module 8, another road is through detecting the crop top, be used to close counting, the rolling counters forward of display module 8, reference crop: the ultrasonic pulse string of supersonic generator 7 outputs is sent into ultrasonic emitting head high voltage difference driver module A14 and is carried out power amplification, drive reference crop top ultrasonic emitting head 16 to reference crop top ultrasonic reflections plate 45 emission ultrasonic, the ultrasonic that reference crop top ultrasonic reflections plate 45 reflects by reference crop top ultrasonic receive 18 receive, reference crop top ultrasonic reception 18 a receipts ultrasonic signal that connect are sent into difference amplifier A20 and are tentatively amplified, the form that adopts difference to amplify is to improve signal to noise ratio in order better to suppress common-mode noise, after difference is amplified, send into gain-controlled amplifier A22 and further be amplified to desired amplitude, after gain control is amplified, send into high Q value bandpass filter A24 and carry out bandpass filtering, filtering band external noise, reduce the signal amplitude that departs from dominant frequency simultaneously, behind bandpass filtering, send into half-wave rectifier A26 and carry out halfwave rectifier, after removing half cycle, send into varying index amplifier A28, index as a fixed voltage carries out the varying index amplification to this fixed voltage, the purpose that varying index amplifies, be under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make each peak value of pulse point both sides more precipitous simultaneously, the pulse of convenient identification amplitude maximum and the accurate position of peak point thereof, after varying index amplifies, send into thresholding comparison module A30 and carry out Threshold detection, find out the pulse of amplitude maximum, send into differential and zero passage detection modules A 32 again, carry out differential and zero passage detection, find out amplitude maximum impulse peak point, open by counting, close control module 4 enabling countings, the rolling counters forward of display module 8, detect crop: the ultrasonic pulse string of supersonic generator 7 outputs is sent into ultrasonic emitting head high voltage difference driver module B13 and is carried out power amplification, drive to detect crop top ultrasonic emitting head 15 to detecting crop top ultrasonic reflections plate 47 emission ultrasonic, detect ultrasonic that crop top ultrasonic reflections plate 47 reflects by reference crop top ultrasonic receive 17 receive, detect crop top ultrasonic to receive 17 a receipts ultrasonic signal that connect and send into difference amplifier B19 and tentatively amplify, the form that adopts difference to amplify is to improve signal to noise ratio in order better to suppress common-mode noise, after difference is amplified, send into gain-controlled amplifier B21 and further be amplified to desired amplitude, after gain control is amplified, send into high Q value bandpass filter B23 and carry out bandpass filtering, filtering band external noise reduces the signal amplitude that departs from dominant frequency, simultaneously behind bandpass filtering, send into half-wave rectifier B25 and carry out halfwave rectifier, send into varying index amplifier B27 after removing half cycle, as the index of a fixed voltage this fixed voltage is carried out varying index and amplify the purpose that varying index amplifies, be under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make each peak value of pulse point both sides more precipitous simultaneously, the pulse of convenient identification amplitude maximum and the accurate position of peak point thereof, after varying index amplifies, send into thresholding comparison module B29 and carry out Threshold detection, find out the pulse of amplitude maximum, send into differential and zero passage detection module B31 again, carry out differential and zero passage detection, find out amplitude maximum impulse peak point, open by counting, close control module 4 and close counting, the rolling counters forward of display module 8, counting opens, close control module 4 and close counting, start comparative result time-delay sampling and the time-delay sample circuit work that keeps module 11 inside in the time of the rolling counters forward of display module 8; Counting, the rolling counters forward result of display module 8 sends into count value with counting preset module 9 predefined count threshold and count threshold comparison module 10 compares, comparative result is sent into comparative result time-delay sampling and is kept module 11 for reading, comparative result time-delay sampling and maintenance module 11 are after suitable time-delay result to be compared is stable, compared result is sampled and is kept, send into small amount irrigation system 12 again, if comparative result is a counting, the rolling counters forward value of display module 8 is less than counting preset module 9 predefined count threshold, small amount irrigation system 12 will be activated, carrying out small amount irrigates, sun landing, after being lower than the threshold value that sets when illumination, the output of illumination threshold test module 1 resets the integrated value zero clearing of illumination integral threshold detection module 2, withdrawed from window detection time, stopping 3 work of ultrasonic transmission interval control module and comparative result time-delay sampling and maintenance module 11 are resetted to extinguish charactron simultaneously shows, control device has entered resting state to save power consumption

Described detection time window, reaching the illumination integral threshold is the necessary condition that enters window detection time, cloudy day does not reach the illumination threshold value, the integrated value of illumination integral threshold detection module 2 still is in and is cleared reset mode, even cloudy weather has reached the illumination threshold value sometime, the output of illumination threshold test module 1 has started 2 pairs of intensities of illumination of illumination integral threshold detection module and has carried out integration, but, before reaching the illumination integral threshold sometime, illumination has been lower than the threshold value that sets again, the output of illumination threshold test module 1 will make the integrated value of illumination integral threshold detection module 2 be cleared again to reset, still do not reach the illumination integral threshold, therefore, cloudy day and cloudy weather all do not enter window detection time, control device still is in resting state and can change, and makes the detection time window drop on the noon 12 of fine weather between at 16 o'clock in afternoon by adjusting illumination threshold value and illumination integral threshold

Described counting preset module 9 predefined count threshold are to determine like this, at first, according to the susceptibility of kind plant to arid, ultrasonic transition time crop water shortage index Ultrasonic TOF CWSI when determining to need to irrigate, then, get the last time small amount and irrigate the rolling counters forward value of the afternoon 14 o'clock countings in back the 4th day (overcast and rainy cloudy weather is postponed), display module 8, as Δ t _P, with Ultrasonic TOF CWSI and Δ t _PSubstitution formula (1-8), that is:

Count threshold=(1-Ultrasonic TOF CWSI) Δ t _P

Embodiment: see Fig. 2, be positioned at Due South to the sun 40, be used to refer to the orientation in the drawings; The 46th, the detection crop of contour cultivation from east to west; Support 41 is used for fixing the relative position of following each several part; A word horizontally leaves some rectangle simulation leaves of placing sidewards 42 of appropriate gap mutually and is positioned at the deep bead 43,44 of simulating both sides, leaf 42 north and south and formed the reference crop that does not produce transpiration from east to west;

The east in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level reference crop top ultrasonic emitting head 16 and reference crop top ultrasonic have been installed successively and have been received 18, ultrasonic receives 18 dead ahead along reference crop level one word arranged direction above ultrasonic emitting head 16 and reference crop above the reference crop, the west end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate 45 has been installed; Ultrasonic above ultrasonic emitting head 16 and the reference crop above the distance reference crop receive 18 far away under, apart from detect crop 46 nearer directly over perpendicular to detect crop 46 contour cultivation direction levels successively correspondence detection crop top ultrasonic emitting head 15 has been installed and has been detected crop top ultrasonic and received 17, ultrasonic receives 17 dead ahead along detection crop 46 contour cultivation directions above ultrasonic emitting head 15 above the detection crop and detection crop, be positioned at detect crop 46 directly over perpendicular to detecting crop 46 contour cultivation directions detection crop top ultrasonic reflections plate 47 has been installed, detect crop top ultrasonic emitting head 15 and detect crop top ultrasonic receive 17 to the distance that detects crop top ultrasonic reflections plate 47 and reference crop top ultrasonic emitting head 16 and reference crop top ultrasonic receive 18 above the reference crop distances of ultrasonic reflections plate 45 equate.

Fig. 4,5,6,7,8,9,10,11,12,13,14,15 is the embodiments of the invention circuit diagram, and is as follows with the corresponding relation of Fig. 3:

Integrated circuit U15B among Fig. 4, photo resistance GR2 and potentiometer RV2 have formed the illumination threshold test module 1 of Fig. 3, and wherein, RV2 is used to adjust the illumination threshold value.Integrated circuit U23, U13 among Fig. 4, capacitor C 46, photo resistance GR1, potentiometer RV1, resistance R 8, resistance R 15, LED 2 have been formed the illumination integral threshold detection module 2 of Fig. 3, wherein, potentiometer RV1 is used to adjust the illumination integral threshold, and LED 2 is used to indicate the duty of illumination integral threshold detection module 2.Integrated circuit U15D, U15C among Fig. 4, electric capacity 51, resistance R 16, R19 have formed the ultrasonic transmission interval control module 3 of Fig. 3.The ultrasonic pulse number control that the left side of integrated circuit U6 among Fig. 5, U14, toggle switch S1, diode D2, D3, resistance R 17 have been formed Fig. 3 is provided with module 6, and the waveform of last pulse of every group of ultrasonic pulse string that diode D2, D3 wherein, resistance R 17 are used to guarantee that supersonic generator 7 produces is complete.Integrated circuit U24A, U24B among Fig. 5, U24C, U24D, resistance R 18, R7, potentiometer RV3, capacitor C 52, diode D4, D5 have formed the supersonic generator 7 of Fig. 3, wherein, potentiometer RV3 is used to adjust ultrasonic frequency, and diode D4, D5 are used to guarantee first cycle of oscillator of supersonic generator 7 and the uniformity in cycle subsequently.Integrated circuit U21 among Fig. 6, capacitor C 36, C39, C40, C41, C47, C48 have formed the ultrasonic emitting head high voltage difference driver module A14 of Fig. 3.Integrated circuit U22 among Fig. 6, capacitor C 38, C42, C43, C44, C49, C50 have formed the ultrasonic emitting head high voltage difference driver module B13 of Fig. 3.The counting that the right-hand part of integrated circuit U6 among integrated circuit U11, U12 among Fig. 7, U16, triode Q2, Q3, resistance R 3, R4, R9, R10, R12, R13 and Fig. 5, resistance R 20, diode D6, capacitor C 65 have been formed Fig. 3 opens and closes control module 4.Integrated oscillation module OSC1 among Fig. 8 has formed the counting oscillator 5 of Fig. 3.Triode Q4 among integrated circuit U7, U8 among integrated circuit U17, U18, U19, U20 and Fig. 9 among Fig. 8, U9, U10, charactron SM1, SM2, SM3, SM4 and Fig. 4, resistance R 14, R11 have formed counting, the display module 8 of Fig. 3.Resistor chain ZP1, ZP2 among Figure 10, ZP3, ZP4, BCD toggle switch SB1, SB2, SB3, SB4 have formed the counting preset module 9 of Fig. 3.Integrated circuit U1, U2 among Figure 11, U3, U4 have formed count value and the count threshold comparison module 10 of Fig. 3, integrated circuit U15A among integrated circuit U5 among Figure 11, triode Q1, diode D1, capacitor C 9, resistance R 1, R2, R5, R6, LED 1 and Fig. 4 has formed the comparative result time-delay sampling and maintenance module 11 of Fig. 3, and LED 1 wherein is used to indicate count value and count threshold comparative result.Integrated circuit U25 among Figure 12, resistance R 21, R22, R23, R24, R25, R26, R27, capacitor C 51, C52, C53, C54, C55 have formed the difference amplifier A20 of Fig. 3, resistance R 21 wherein, R22, R23, R24, capacitor C 51, C52, C53, C54, C55 have formed passive filter and have been used for the inhibition zone external noise, and R23, R24 provide a DC return path for the U25 input bias current simultaneously.Integrated circuit U26 among Figure 12, resistance R 28, R29, R30, potentiometer RV4, capacitor C 60, C61, C62, C63, C64, C67, C68 have formed the gain-controlled amplifier A22 of Fig. 3, and wherein, potentiometer RV4 is used to adjust gain amplifier.Integrated circuit U27 among Figure 13, resistance R 31, R32, R33, R34, R35, R36, R37, R38, capacitor C 71, C72 has formed the high Q value bandpass filter A24 of Fig. 3, diode D7 among Figure 13, resistance R 39 has been formed the half-wave rectifier A26 of Fig. 3, integrated circuit U28 among Figure 13, resistance R 40, R41, R42, capacitor C 79, standard of precision voltage DV1 has formed the varying index amplifier A28 of Fig. 3, integrated circuit U29 among Figure 13, resistance R 43, R44, capacitor C 80 has been formed the thresholding comparison module A30 of Fig. 3, integrated circuit U30 among Figure 13, resistance R 45, R46, R47, R48, capacitor C 82, triode Q5 has formed differential and the zero passage detection modules A 32 of Fig. 3, integrated circuit U31 among Figure 14, resistance R 49, R50, R51, R52, R53, R54, R55, capacitor C 88, C89, C90, C91, C92 has formed the difference amplifier B19 of Fig. 3, resistance R 49 wherein, R50, R51, R52, capacitor C 88, C89, C90, C91, C92 has formed passive filter and has been used for inhibition zone external noise, R51, R52 provides a DC return path for the B31 input bias current simultaneously.Integrated circuit U32 among Figure 14, resistance R 56, R57, R58, potentiometer RV5, capacitor C 97, C98, C99, C100, C101, C104, C105 have formed the gain-controlled amplifier B21 of Fig. 3, and wherein, potentiometer RV5 is used to adjust gain amplifier.Integrated circuit U33 among Figure 15, resistance R 59, R60, R61, R62, R63, R64, R65, R66, capacitor C 106, C107 has formed the high Q value bandpass filter B23 of Fig. 3, diode D8 among Figure 15, resistance R 67 has been formed the half-wave rectifier B25 of Fig. 3, integrated circuit U34 among Figure 15, resistance R 68, R69, R70, capacitor C 112, standard of precision voltage DV2 has formed the varying index amplifier B27 of Fig. 3, integrated circuit U35 among Figure 15, resistance R 71, R72, capacitor C 117 has been formed the thresholding comparison module B29 of Fig. 3, the integrated circuit U36 among Figure 15, resistance R 73, R74, R75, R76, capacitor C 119, triode Q6 has formed differential and the zero passage detection module B31 of Fig. 3.

Unaccounted electric capacity is the electrical power by-pass filter capacitor.Integrated circuit: U1, U2, U2, the U4 model is 74LS85, U5, the U6 model is CD4013, U7, U8, U9, the U10 model is 74LS248, U11, the U12 model is 6N137, U13, the U14 model is CD4017, and the U15 model is CD4093, and the U16 model is 74HC74, U17, U18, U19, the U20 model is 74LS160, U21, the U22 model is MAX232, and the U23 model is CD4060, and the U24 model is CD4011, U25, the U31 model is AD830, U26, the U32 model is AD605, U27, the U33 model is MAX275, U28, the U34 model is VCA810, U29, the U35 model is LM360, U30, the U36 model is LM361.Integrated oscillator module OSC1 frequency is 20M.

Claims (8)

1. method of irrigating according to crop water shortage degree control is characterized in that:

At first, place and detect crop (46) environment facies place together, reference crop level one word layout with not producing rising reference crop; At the end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction, reference crop top ultrasonic emitting head (16) is installed level successively and reference crop top ultrasonic receives (18); Ultrasonic emitting head (16) and reference crop top ultrasonic receives the dead ahead of head (18) along reference crop level one word arranged direction above reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate (45) is installed; Be positioned at detect crop (46) directly over receive (17) perpendicular to detecting crop (46) contour cultivation direction level, be equipped with successively to detect crop top ultrasonic emitting head (15) and detect crop top ultrasonic; Receive head (17) along dead ahead of detecting crop (46) contour cultivation direction detecting above the crop ultrasonic emitting head (15) and detect crop top ultrasonic, be positioned at detect crop (46) directly over be equipped with and detect ultrasonic reflections plate (47) above the crop perpendicular to detecting crop (46) contour cultivation direction; Detect crop top ultrasonic emitting head (15) and detect crop top ultrasonic and receive head (17) and receive (18) distance of ultrasonic reflections plate (45) above the reference crop to the distance that detects crop top ultrasonic reflections plate (47) and reference crop top ultrasonic emitting head (16) and reference crop top ultrasonic and equate;

Secondly, determine window detection time by illumination threshold test module (1) and illumination integral threshold detection module (2), after reaching the threshold value that sets when illumination, illumination threshold test module (1) starts illumination integral threshold detection module (2) intensity of illumination is carried out integration, after reaching the illumination integral threshold that sets, enter window detection time, after being lower than the threshold value that sets when illumination, the output of illumination threshold test module (1) resets the integrated value zero clearing of illumination integral threshold detection module (2), withdraws from window detection time;

The 3rd, after entering window detection time, ultrasonic transmission interval control module (3) is activated, produce one group of ultrasonic pulse string by time interval control supersonic generator (6), this train of pulse is divided into two-way, lead up to reference crop top ultrasonic emitting head (16), another road sends simultaneously by detecting crop top ultrasonic emitting head (15); After reference crop top ultrasonic reception head (18) is received by the ultrasonic that ultrasonic reflections plate (45) reflects above the reference crop, confirm the time point that ultrasonic arrives, in the rolling counters forward of confirming enabling counting on the time point that ultrasonic arrives, display module (8), after detection crop top ultrasonic receives a ultrasonic of (17) receiving that ultrasonic reflections plate (47) reflects above the detected crop, confirm the time point that ultrasonic arrives, in the rolling counters forward of confirming to close on the time point that ultrasonic arrives counting, display module (8);

The 4th, to count, the count value of the counter of display module (8) with compare by counting the predefined count threshold of preset module (9) according to ultrasonic transition time crop water shortage index, if the count threshold that the count value of the counter of counting, display module (8) sets less than counting preset module (9), crop water shortage has reached the degree that needs irrigation, will start small amount irrigation system (12);

Described ultrasonic transition time crop water shortage index is definition like this, ultrasonic transition time crop water shortage index:

(1-8) Δ t is the ultrasonic transit time difference of actual detection crop canopies top and reference crop canopy top in the formula, Δ t _PBe the ultrasonic transit time difference of potential or maximum detection crop canopies top with reference crop canopy top, Δ t _PThe maximum Δ t value replacement of actual measurement during available abundant supply water, the reference crop canopy refers to the simulation leaf part that reference crop is accepted solar radiation; When crop not during lack of water because of the rising cooling extent maximum that produces of crop plant, the ultrasonic transit time difference Δ t maximum above corresponding with it detection crop canopies top and the reference crop canopy is with Δ t _PIdentical, Ultrasonic TOF CWSI result of calculation is 0, expression detects not lack of water of crop, in like manner, when the complete water stress of crop stops the crop plant transpiration, because of the rising cooling extent minimum that produces of crop plant, the corresponding with it detection crop canopies top and the ultrasonic transit time difference Δ t minimum of reference crop canopy top, Δ t is 0, Ultrasonic TOFCWSI result of calculation is 1, and expression detects crop and stops transpiration and be in complete water stress state, and Ultrasonic TOF CWSI is the indication crop water degree that wanes, be in the numerical quantities between 0 and 1, the big more expression crop water shortage degree of numerical value is high more;

The 5th, withdraw from window detection time after, ultrasonic transmission interval control module (3) is closed, except that illumination threshold test module (1) still work, all the other enter resting state to save power consumption.

2. the method that control is irrigated according to crop water shortage degree according to claim 1 is characterized in that: described reference crop is horizontally left each rectangle of placing sidewards simulation leaf (42) in gap mutually and is positioned at preceding deep bead (43), the rear wind-break panels (44) of simulating leaf (42) both sides along the horizontal direction of simulation leaf (42) one words by a word to be formed.

3. the method that control is irrigated according to crop water shortage degree according to claim 1, it is characterized in that: described detection time window, reaching the illumination integral threshold is the necessary condition that enters window detection time, cloudy day does not reach the illumination threshold value, the integrated value of illumination integral threshold detection module (2) still is in and is cleared reset mode, even cloudy weather has reached the illumination threshold value sometime, the output of illumination threshold test module (1) has started illumination integral threshold detection module (2) intensity of illumination has been carried out integration, but before reaching the illumination integral threshold sometime, illumination has been lower than the threshold value that sets again, the output of illumination threshold test module (1) will make the integrated value of illumination integral threshold detection module (2) be cleared again to reset, still do not reach the illumination integral threshold, cloudy day and cloudy weather all do not enter window detection time, make the detection time window drop on the noon 12 of fine weather between at 16 o'clock in afternoon by adjustment illumination threshold value and illumination integral threshold.

4. the method that control is irrigated according to crop water shortage degree according to claim 1, it is characterized in that: the described ultrasonic pulse string that sends simultaneously by reference crop top ultrasonic emitting head (16) and detection crop top ultrasonic emitting head (15), have identical frequency and phase place, include identical pulse number, it is the upper limit that pulse number still is " rhombus " with the ultrasonic pulse string waveform that receives.

5. the method that control is irrigated according to crop water shortage degree according to claim 1, it is characterized in that: the time point that described ultrasonic arrives is to confirm like this: after reference crop top ultrasonic receives head (18) and detects crop top ultrasonic and receives the ultrasonic that head (17) receives that respectively ultrasonic reflections plate (47) reflects above reference crop top ultrasonic reflections plate (45) and the detection crop, send into difference amplifier A (20) respectively, difference amplifier B (19), after difference is amplified, send into gain-controlled amplifier A (22) respectively, gain-controlled amplifier B (21), after gain control is amplified, send into high Q value bandpass filter A (24) respectively, high Q value bandpass filter B (23), behind bandpass filtering, send into half-wave rectifier A (26) respectively, half-wave rectifier B (25) carries out halfwave rectifier, after removing half cycle, send into varying index amplifier A (28) respectively, varying index amplifier B (27), index as a fixed voltage carries out the varying index amplification to this fixed voltage respectively respectively, under the situation that does not change remaining each peak value of pulse point relative time position of half cycle, draw back the amplitude disparity of each peak value of pulse point, make each peak value of pulse point both sides more precipitous simultaneously, after varying index amplifies, send into thresholding comparison module A (30) respectively, thresholding comparison module B (29) carries out Threshold detection, find out the pulse of amplitude maximum, send into differential and zero passage detection modules A (32) more respectively, differential and zero passage detection module B (31), carry out differential and zero passage detection, find out amplitude maximum impulse peak point separately, be respectively reference crop top ultrasonic reception head (18) and receive that the time point of the ultrasonic arrival that is reflected by reference crop top ultrasonic reflections plate (45) and detection crop top ultrasonic receive the time point that (17) receive the ultrasonic arrival that detected crop top ultrasonic reflections plate (47) reflects.

6. the method that control is irrigated according to crop water shortage degree according to claim 1, it is characterized in that: the count value of the counter of described counting, display module (8) is " the ultrasonic transit time difference Δ t of actual detection crop canopies top and reference crop canopy top " in the ultrasonic transition time crop water shortage formula of index (1-8), the potential or maximum detection crop canopies top in the formula (1-8) and the ultrasonic transit time difference Δ t of reference crop canopy top _P, fully invade profit with irrigating the back root soil, crop is supplied water, and the maximum Δ t value of actual measurement replaces when sufficient, irrigates for small amount, and counted in the 4th day afternoon 14 o'clock the back with irrigating, the count value of the counter of display module (8);

The predefined count threshold of described counting preset module (9) is to determine like this, at first, according to the susceptibility of kind plant to arid, ultrasonic transition time crop water shortage index Ultrasonic TOF CWSI when determining to need to irrigate, then, get the last time small amount and irrigate the count value of the counter of the 4th day afternoon 14 o'clock countings in back, display module (8), as Δ t _P, with Ultrasonic TOF CWSI and Δ t _PSubstitution formula (1-8), that is: the Δ t of count threshold=(1-UltrasonicTOFCWSI) _P

7. device of irrigating according to crop water shortage degree control, it is characterized in that: will can not produce rising reference crop and place and detect crop (46) environment facies place together, reference crop level one word is arranged, end in reference crop level one word layout, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction level, reference crop top ultrasonic emitting head (16) and reference crop top ultrasonic is installed successively receives (18); Ultrasonic emitting head (16) and reference crop top ultrasonic receives the dead ahead of head (18) along reference crop level one word arranged direction above reference crop, the other end that reference crop level one word is arranged, be positioned at reference crop directly over perpendicular to reference crop level one word arranged direction reference crop top ultrasonic reflections plate (45) is installed; Be positioned at detect crop (46) directly over receive (17) perpendicular to detecting crop (46) contour cultivation direction level, be equipped with successively to detect crop top ultrasonic emitting head (15) and detect crop top ultrasonic; Receive head (17) along dead ahead of detecting crop (46) contour cultivation direction detecting above the crop ultrasonic emitting head (15) and detect crop top ultrasonic, be positioned at detect crop (46) directly over be equipped with and detect ultrasonic reflections plate (47) above the crop perpendicular to detecting crop (46) contour cultivation direction; Detect crop top ultrasonic emitting head (15) and detect crop top ultrasonic and receive head (17) and receive (18) distance of ultrasonic reflections plate (45) above the reference crop to the distance that detects crop top ultrasonic reflections plate (47) and reference crop top ultrasonic emitting head (16) and reference crop top ultrasonic and equate;

Control device comprises following each several part: illumination threshold test module (1), illumination integral threshold detection module (2), ultrasonic transmission interval control module (3), counting opens and closes control module (4), counting oscillator (5), the control of ultrasonic pulse number is provided with module (6), supersonic generator (7), counting, display module (8), counting preset module (9), count value and count threshold comparison module (10), comparative result time-delay sampling and maintenance module (11), small amount irrigation system (12); Ultrasonic transmits and receives the two-way that part is divided into symmetrical structure, one the tunnel is relevant with reference crop, they are ultrasonic emitting head high voltage difference driver module A (14), reference crop top ultrasonic emitting head (16), reference crop top ultrasonic receives head (18), difference amplifier A (20), gain-controlled amplifier A (22), high Q value bandpass filter A (24), half-wave rectifier A (26), varying index amplifier A (28), thresholding comparison module A (30), differential and zero passage detection modules A (32), another road is relevant with the detection crop, they are ultrasonic emitting head high voltage difference driver module B (13), detect crop top ultrasonic emitting head (15), detect crop top ultrasonic and receive head (17), difference amplifier B (19), gain-controlled amplifier B (21), high Q value bandpass filter B (23), half-wave rectifier B (25), varying index amplifier B (27), thresholding comparison module B (29), differential and zero passage detection module B (31);

The control device each several part connects as follows: illumination threshold test module (1) output is connected with illumination integral threshold detection module (2); Illumination integral threshold detection module (2) output is connected with keeping module (11) with comparative result time-delay sampling with ultrasonic transmission interval control module (3) respectively; Ultrasonic transmission interval control module (3) output opens and closes the control of control module (4) and ultrasonic pulse number with counting respectively and module (6) is set is connected; Counting opens and closes control module (4) with oscillator (5) output and counting and is connected; Counting opens and closes control module (4) output and is connected with keeping module (11) with counting, display module (8) and comparative result time-delay sampling respectively; Counting, display module (8) output are connected with count threshold comparison module (10) with count value; Counting preset module (9) output is connected with count threshold comparison module (10) with count value; Count value is connected with keeping module (11) with comparative result time-delay sampling with count threshold comparison module (10) output; Comparative result time-delay sampling is connected with small amount irrigation system (12) with keeping module (11) output; The control of ultrasonic pulse number is provided with module (6) output and is connected with supersonic generator (7); The output of supersonic generator (7) is divided into two-way, be symmetrical structure, one the tunnel through the reference crop top, the rolling counters forward that is used for enabling counting, display module (8), another road is through detecting the crop top, be used to close the rolling counters forward of counting, display module (8), reference crop: supersonic generator (7) output is connected with ultrasonic emitting head high voltage difference driver module A (14); Ultrasonic emitting head high voltage difference driver module A (14) output is connected with reference crop top ultrasonic emitting head (16); Reference crop top ultrasonic receives head (18) output and is connected with difference amplifier A (20); Difference amplifier A (20) output is connected with gain-controlled amplifier A (22); Gain-controlled amplifier A (22) output is connected with high Q value bandpass filter A (24); High Q value bandpass filter A (24) output is connected with half-wave rectifier A (26); Half-wave rectifier A (26) output is connected with varying index amplifier A (28); Varying index amplifier A (28) output is connected with thresholding comparison module A (30); Thresholding comparison module A (30) output is connected with zero passage detection modules A (32) with differential; Differential opens and closes control module (4) with zero passage detection modules A (32) output and counting and is connected, the rolling counters forward that is used for enabling counting, display module (8), detect crop: supersonic generator (7) output is connected with ultrasonic emitting head high voltage difference driver module B (13); Ultrasonic emitting head high voltage difference driver module B (13) output is connected with detection crop top ultrasonic emitting head (15); Detecting crop top ultrasonic reception head (a 17) output is connected with difference amplifier B (19); Difference amplifier B (19) output is connected with gain-controlled amplifier B (21); Gain-controlled amplifier B (21) output is connected with high Q value bandpass filter B (23); High Q value bandpass filter B (23) output is connected with half-wave rectifier B (25); Half-wave rectifier B (25) output is connected with varying index amplifier B (27); Varying index amplifier B (27) output is connected with thresholding comparison module B (29); Thresholding comparison module B (29) output is connected with zero passage detection module B (31) with differential; Differential opens and closes control module (4) with zero passage detection module B (31) output and counting and is connected, and is used to close the rolling counters forward of counting, display module (8).

8. the device that control is irrigated according to crop water shortage degree according to claim 7 is characterized in that: described reference crop is horizontally left each rectangle of placing sidewards simulation leaf (42) in gap mutually and is positioned at preceding deep bead (43), the rear wind-break panels (44) of simulating leaf (42) both sides along the horizontal direction of simulation leaf (42) one words by a word to be formed.

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