CN114642099A

CN114642099A - Saline-alkali soil water-saving treatment technology and treatment system

Info

Publication number: CN114642099A
Application number: CN202210315294.1A
Authority: CN
Inventors: 张峰
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-03-28
Filing date: 2022-03-28
Publication date: 2022-06-21
Anticipated expiration: 2042-03-28
Also published as: CN114642099B

Abstract

The invention discloses a water-saving treatment technology and a treatment system for saline-alkali soil. The invention adopts the dilute nitric acid to drip and permeate the soil, can greatly save the water resource consumed in the saline-alkali soil treatment, and achieves the purpose of saving water; then, water control and salt discharge are carried out through the two stages of concealed pipes, the collected water is subjected to electrochemical purification, and the purified water can be returned to be used for farmland irrigation, so that the purpose of water resource recycling is achieved, and the water-saving effect is further achieved. The salt discharge pipe adopts the scheme of multi-aperture permeation and permeation-resistant bottom plates, so that the formation of capillary tubes in soil around the drain pipe is accelerated, the salt metabolism of the soil is accelerated, the permeation of water to a deeper layer is effectively avoided, and the underground water is collected to form a water channel.

Description

Saline-alkali soil water-saving treatment technology and treatment system

Technical Field

The invention relates to the technical field of saline-alkali soil treatment, in particular to a saline-alkali soil water-saving treatment technology and a saline-alkali soil water-saving treatment system.

Background

The salinization of soil is a worldwide problem, the salinized soil area is about 10 hundred million hectares all over the world, 9913 million hectares and about 14.7 hundred million acres are in China, and more than 100 cities in China are located in a saline-alkali soil distribution area. The yield reduction and the land abandoning caused by salinization of agricultural cultivated land are about 5 hundred million mu, and the method is mainly concentrated in arid and semiarid regions in the north China, the northwest China and the northeast China. In addition, in the cultivation process, the chemical fertilizer is excessively applied for a long time, so that the secondary salinization of soil is aggravated, the soil is hardened seriously, and the salinized and alkalized soil is continuously enlarged.

At present, the domestic saline-alkali soil improvement technology is summarized as follows: physical improvement: leveling land, deeply ploughing and sunning upturned soil, loosening soil in time, raising terrain, and changing soil in micro-areas; improvement of hydraulic engineering: irrigation and drainage, fresh salt storage, irrigation and salt washing, and underground salt drainage; chemical improvement: gypsum, phosphogypsum, calcium superphosphate, humic acid, peat, vinegar residue and the like; biological improvement: planting rice, planting sesbania as salt tolerant plant, planting saline alkali tolerant tree, etc. Physical improvement cannot effectively remove saline-alkali components in soil; biological modification usually takes years and has a slow onset of action. The saline-alkali soil is fast to be treated by irrigating and washing salt, the effect is good, but a large amount of water resources are consumed.

Therefore, a water-saving saline-alkali soil treatment technology needs to be developed.

Disclosure of Invention

The invention aims to overcome the problems and provides a saline-alkali soil water-saving treatment technology and a treatment system. In order to achieve the purpose, the invention adopts the following technical scheme:

a water-saving saline-alkali soil treating technology features that the diluted nitric acid solution with 0.005% concentration is used to wash the soil by drip irrigation, the two-stage hidden pipes are used to control water and discharge salt, the salt-discharged waste water is collected to lifting pump station, and the waste water is pumped to purifying pool by lifting pump station and then purified by electrochemical desalting method.

The invention also discloses a water-saving treatment system for the saline-alkali soil, which comprises a salt discharge pipe network, a water channel, a lifting pump station and a purification facility, wherein the salt discharge pipe network and the water channel are formed by two stages of concealed pipes;

the two-stage concealed pipes comprise an upper-layer salt discharge pipe and a lower-layer water-blocking salt discharge pipe, the upper-layer salt discharge pipe and the lower-layer water-blocking salt discharge pipe are connected through a connecting pipe, and a plurality of water drawing holes are formed in the surfaces of the upper-layer salt discharge pipe and the lower-layer water-blocking salt discharge pipe; the upper-layer salt discharge pipe comprises branch pipes and water collecting pipes, wherein the branch pipes form an included angle of 5 degrees with the vertical direction, and are bent into vertically arranged straight pipes at an outlet and then are collected into the water collecting pipes, and the number of the branch pipes and the water collecting pipes is multiple, so that a pipe network is formed; the tail ends of the water collecting pipe and the lower-layer water-blocking salt discharging pipe are communicated with the ditch.

As an improvement, the branched pipe adopts a PVC mesh salt discharge pipe with the diameter of 15-30cm and is buried at the position 70-75cm away from the ground surface on the top of the pipe; the lower layer water-blocking salt-removing pipe adopts a cement product mesh water-blocking calandria, and a mesh pipe with the diameter of 75-150 cm is adopted according to the water level and water quantity of underground water in a region and is buried below the pipe top and 150cm away from the ground surface to a position above the average height of the ground surface water.

As an improvement, the interval of the branch pipes is 10-15m, and the interval of the lower-layer water salt discharge pipe is 150 m.

As a modification, the straight pipe is 5cm in length.

As an improvement, the water drawing holes on the surface of the branch pipe are distributed in a regular triangle shape, the hole diameter of the water drawing holes is in an inverted funnel shape from the outer wall to the inner wall of the branch pipe, and an iron wire filter screen is arranged inside the water drawing holes or the water dividing pipe.

As an improvement, the aperture of the outer wall of the water drawing hole is 2cm, and the aperture of the inner wall of the water drawing hole is 1 cm.

As an improvement, asbestos is filled in the water drawing holes or the water dividing pipes.

As an improvement, the water collecting pipe and the lower-layer water-blocking salt discharging pipe are not provided with water drawing holes within a 90-degree angle range from the center point of the inner diameter to the center point of the inner diameter.

As an improvement, the treatment system also comprises a reservoir, and a lifting pump station, a purification facility and four 100-inch water-retaining tanks 150m are arranged beside the ditch on the land with the standard of more than forty thousand mu³The water reservoir.

The invention has the advantages that:

1. the invention adopts the dilute nitric acid to drip and permeate the soil, can greatly save the water resource consumed in the saline-alkali soil treatment, and achieves the purpose of saving water; and then, water control and salt discharge are carried out through two stages of concealed pipes, the collected water is subjected to electrochemical purification, and the purified water can be returned to be used for farmland irrigation, so that the purpose of water resource recycling is achieved, and the water-saving effect is further achieved.

2. The salt discharge pipe adopts the scheme of multi-aperture permeation and permeation-resistant bottom plates, so that the formation of capillary tubes in soil around the drain pipe is accelerated, the salt metabolism of the soil is accelerated, the permeation of water to a deeper layer is effectively avoided, and the underground water is collected to form a water channel.

Drawings

FIG. 1 is a schematic view of a treating system according to example 1;

FIG. 2 is a structural view of a water drawing hole in example 1;

FIG. 3 is a structural view of a branched pipe in example 1;

FIG. 4 is a distribution diagram of the water drawing holes in example 1.

The following are marked in the figure:

1-salt discharge pipe network, 11-upper-layer salt discharge pipe, 111-branch pipe, 112-water collecting pipe, 113-straight pipe, 12-lower-layer water-blocking salt discharge pipe, 13-connecting pipe, 14-water suction hole, 2-water channel, 3-lifting pump station, 4-purification facility and 5-reservoir.

Detailed Description

The present invention will be described in detail and specifically with reference to the following examples so as to facilitate the understanding of the present invention, but the following examples do not limit the scope of the present invention.

Example 1

The embodiment discloses a saline and alkaline land water conservation administers technique, uses the dilute nitric acid solution that concentration is 0.005% to pass through to drip irrigation infiltration soil washing, carries out accuse water through the two-stage hidden pipe and arranges salt, and the salt waste water of row assembles to the promotion pump station through the ditch, is purified waste water back cyclic utilization through the electrochemistry desalination method to the purification pond with waste water extraction by the promotion pump station.

The electrochemical purification method is characterized in that current is introduced into a cathode and an anode which are placed in a solution, so that electrochemistry and secondary redox reaction are brought. The cathode metal is protected, electrons are forced to flow into the cathode, the metal can not lose electrons to enter the solution, and on the cathode, cations in the solution obtain electrons, and the order of the obtained electrons is opposite to that of the metal. The anode, with the exception of the inert electrode (C-rod, Pt), loses electrons into solution in the same order as the metallic order. If the anode is an inert electrode, the anions in the solution lose electrons, and the sulfur ions, iodine ions, bromine ions, chlorine ions, hydroxyl ions, fluorine ions and oxygen-containing acid ions are sequentially removed, and finally the salt in the water is purified. The purified water is returned to the field for irrigation.

The invention also discloses a water-saving treatment system for the saline-alkali soil, which comprises a salt discharge pipe network 1 formed by two stages of concealed pipes, a water channel 2, a lifting pump station 3, a purification facility 4 and a reservoir 5. A lifting pump station 3, a purification facility 4 and four water reservoirs 5 of 100 plus 150m are arranged beside the ditch 2 in the land of more than forty thousand mu standard.

The salt discharge pipe network 1 comprises an upper layer salt discharge pipe 11 and a lower layer water-blocking salt discharge pipe 12, the upper layer salt discharge pipe 11 and the lower layer water-blocking salt discharge pipe 12 are connected through a connecting pipe 13, and a plurality of water drawing holes 14 are formed in the surfaces of the upper layer salt discharge pipe 11 and the lower layer water-blocking salt discharge pipe 12.

The upper-layer salt discharge pipe 11 comprises a branch pipe 111 and a water collecting pipe 112, the branch pipe 111 forms an included angle of 5 degrees with the vertical direction, and is bent into a vertically arranged straight pipe 113 at an outlet and then is collected into the water collecting pipe 112, the number of the branch pipes 111 and the water collecting pipe 112 is multiple, and a pipe network is formed; the end of the water collecting pipe 112 and the lower layer water-blocking salt-removing pipe 12 are both communicated with the ditch 2.

The branched pipe 111 adopts a PVC mesh salt discharge pipe with the diameter of 15-30cm and is buried in the position 70-75cm away from the ground surface at the top of the pipe; the lower layer water-blocking salt-removing pipe 12 adopts a cement mesh water-blocking calandria, and adopts a mesh pipe with the diameter of 75cm-150cm according to the water level and water quantity of underground water in a region, and the mesh pipe is buried below the pipe top and 150cm away from the ground surface to a position above the average height of the ground surface water. The water drawing holes 14 on the surface of the branch pipe 111 are distributed in a regular triangle, the diameter of the water drawing holes 14 is in an inverted funnel shape from the outer wall to the inner wall of the branch pipe, the diameter of the outer wall is 2cm, and the diameter of the inner wall is 1 cm. Iron wire filter screens are arranged in the water drawing holes 14 and the water distribution pipes 111, and asbestos is filled in the water drawing holes and the water distribution pipes.

The water collecting pipe 112 and the lower layer water-proof salt discharging pipe 12 are not provided with water drawing holes 14 within a vertically downward 90-degree angle range by taking the center point of the inner diameter as the center of a circle.

In this embodiment, the spacing between the branch pipes 111 is 10-15m, and the spacing between the salt discharge pipes 12 of the lower layer group is 100-150 m. The straight pipe 113 is 5cm in length.

The invention designs a comparison test:

first, preparation of test

1. A land simulation box: the bottom of a double-side transparent glass test box 6 (specification 300X 200) is perforated a plurality of times, and the bottom is raised by 1 cm; the bottom of a double-side transparent glass test box 1 (specification 700 x 200) is perforated a plurality of times, and the bottom is raised by 1 cm; the cistern 4 seat (format 320 x 220 x 70).

2. A salt discharge pipeline: the PVC net pipes are 275cm long, 1cm in wall thickness and 5cm in inner diameter, the staggered holes are spaced by 10cm in length, 275cm in length, 1cm in wall thickness and 3.5cm in inner diameter, the staggered holes are spaced by 10cm in length, 275cm in wall thickness and 12cm in inner diameter, the staggered holes are spaced by 10cm in length, 275cm in length, 1cm in wall thickness and 7.5cm in inner diameter, and the staggered holes are spaced by 10cm in length.

3. The electrochemical water purification device comprises: the electrode bar, the 380V power supply, the primary filtering device and the water storage tank are arranged.

4. The Bayankeelsh quinqueuene severe saline-alkali soil is a plurality of (un-improved), and the saline-alkali soil and the common sandy soil are improved by a gypsum method.

5. Drip irrigation simulation: the rubber water pipe has a plurality of lengths

6. And (3) spraying simulation: the shower head sprays a plurality of shower heads

7. A plurality of waterproof cloths (prevent the rain from influencing the experimental result)

Second, test time

The experiment was divided into two phases, each of which was 4 months (from the beginning of 5 months to the beginning of 10 months per year).

Third, the test procedure

1. Test subjects: bayan Yan Er city Wuyuan county saline-alkali soil (not improved), saline-alkali soil improved by gypsum method, and common sandy soil.

2. Simulating the experimental conditions: different water requirements of crop varieties are different, for experimental uniformity, the average farmland irrigation watering period and the watering duration are referred, and experiments are carried out for 4 hours by taking the average value of 96 hours as a watering period and watering once. The climatic conditions are outdoor, the outdoor average temperature is 10-32 ℃ during the experiment, and the outdoor average temperature is west wind, northwest wind, windy wind and little rainfall.

3. Grouping experiments, and establishing six groups of experimental models:

experimental model group a. Three salt discharge pipes with the inner diameter of 5cm are arranged at a distance of 1m from the surface layer of the soil at 70cm, and two water-blocking discharge pipes with the inner diameter of 12cm are arranged at a distance of 2m from the surface layer of the soil at 1.5-1.8 m. (the upper layer salt discharge pipe and the lower layer water-proof salt discharge pipe are not provided with holes at the bottoms, and water drawing holes are not arranged in the range of a central angle of vertically downwards 90 degrees by taking the central point of the inner diameter of the salt discharge pipe as the center of a circle), the salt discharge pipe is placed to form an angle of 5 degrees with the ground, then the device is placed in a water storage tank, and the water storage tank is internally provided with a water storage tank with the depth of 15cm and the concentration of 15g/cm³Na2CO3 solution.

Group B experimental models. Three salt discharge pipes with the inner diameter of 5cm are arranged at a distance of 1m from the surface layer of the soil at a position of 70cm, two water-blocking discharge pipes with the inner diameter of 12cm are arranged at a distance of 1.5-1.8 m from the surface layer of the soil, the salt discharge pipes with the distance of 2m (the periphery of the salt discharge pipes are distributed at intervals of 10 cm) are arranged at an angle of 5 degrees with the ground, the device is arranged in a water storage tank, the water storage tank is internally provided with a water storage tank with the depth of 15cm and the concentration of 15g/cm³The Na2CO3 solution was used to simulate high salt groundwater.

And C, experimental model. Two salt discharge pipes with the inner diameter of 5cm are arranged at a distance of 1m from the surface layer of the soil at 40cm, and two water-blocking discharge pipes with the inner diameter of 12cm are arranged at a distance of 2m from the surface layer of the soil at 1.5-1.8 m. (the upper layer salt discharge pipe and the lower layer water-proof salt discharge pipe are not provided with holes at the bottoms, and water drawing holes are not arranged in the range of a central angle of vertically downwards 90 degrees by taking the central point of the inner diameter of the salt discharge pipe as the center of a circle), the salt discharge pipe is placed to form an angle of 5 degrees with the ground, then the device is placed in a water storage tank, and the water storage tank is internally provided with a water storage tank with the depth of 15cm and the concentration of 15g/cm³Na2CO3 solution.

And D, experimental models. By using a 700 x 200 x 150 specification experiment box, two salt discharge pipes with the inner diameter of 5cm are placed at a distance of 5m from the surface layer of soil, three water-blocking discharge pipes with the inner diameter of 12cm are placed at a distance of 1.5-1.8 m from the surface layer of soil, and the salt discharge pipes at a distance of 2m (the peripheries of the salt discharge pipes are distributed at intervals of 10cm in a staggered manner) are placed at an angle of 5 degrees with the ground.

And E, experimental models. By using a 700 x 200 x 150 specification experimental box, two salt discharge pipes with the inner diameter of 5cm are arranged at a distance of 5m from the surface layer of soil at a position 40cm away from the surface layer of the soil, three water-blocking discharge pipes with the inner diameter of 12cm are arranged at a position 1.5-1.8 m from the surface layer of the soil, and the salt discharge pipes with the distance of 2m (the periphery of the salt discharge pipes are distributed at intervals of 10 cm) are arranged at an angle of 5 degrees with the ground.

And F, experimental models. Three salt discharge pipes with the inner diameter of 5cm are arranged at a distance of 1m from the surface layer of the soil at 70cm, and two water-blocking discharge pipes with the inner diameter of 12cm are arranged at a distance of 2m from the surface layer of the soil at 1.5-1.8 m. (the upper layer salt discharge pipe and the lower layer water-proof salt discharge pipe are not provided with holes at the bottoms, and water drawing holes are not arranged in the range of a central angle of vertically downwards 90 degrees by taking the central point of the inner diameter of the salt discharge pipe as the center of a circle), the salt discharge pipe is placed to form an angle of 5 degrees with the ground, then the device is placed in a water storage tank, and the water storage tank is internally provided with a water storage tank with the depth of 30-70cm and the concentration of 15g/cm³Na2CO3 solution.

4. The experimental steps are as follows:

a. the D, E experimental model is filled with ordinary sandy soil, the water permeability and water drainage of the soil are tested under the normal drip irrigation condition, and the influence change of the distance between the water drainage channels on the water drawing capacity is tested. And (5) checking the process of forming the fixed water system capillary between the soils in the continuous drip irrigation process. And (5) inspecting the influence on the capillary of the deep soil after deep ploughing and rolling the surface soil.

b. The Bayan Rice paper' er city Wuyuan county severe saline-alkali soil is filled with A, B, C, F experimental facilities, 0.005 dilute nitric acid solution is added into the experimental soil through two modes of drip irrigation and spraying, and the final improvement effect of the soil is tested.

c. The method comprises the steps of respectively filling A, B, C experimental devices in saline-alkali soil improved by a gypsum method, adding common water into the experimental soil in a drip irrigation mode and a spraying mode, and testing the final salt elimination effect of the soil.

d. Collecting the waste water after washing soil, treating the waste water through an electrochemical purification facility, and checking the conductivity of the treated water sample.

Fourth, conclusion of experiment

1. Through D, E experimental model comparison of common sandy soil samples, the following results are found:

firstly, according to the drip irrigation frequency of starting drip irrigation every 4 hours and every 4 days, the soil capillary can be normally formed, the formation time is formed after the 14 th drip irrigation is finished, and the time result is two months.

Secondly, after deep ploughing and rolling, the E groups of soil capillary pipes 40cm away from the surface layer of the soil are basically destroyed, and the 18-25cm of capillary pipes are still remained after the observation of the soil capillary pipes 70cm away from the surface layer of the soil through a transparent section.

And thirdly, the fixed capillary tube formation in the water seepage process is facilitated by the additional hole-fixing salt discharge method, the self structural stress problem of the tube body is considered, the equilateral triangle staggered layout with the hole spacing of preferably 10cm can be properly increased along with the inner diameter of the drain pipe, and the hole spacing also needs to be properly increased.

And fourthly, the water loss rate of the soil is higher during the experiment of the group E, the upper-layer salt discharge pipe receives more water seepage, and the obvious water shortage phenomenon appears in the soil on the third day after the drip irrigation is finished compared with the group D. The soil content in the pipe is large, and the soil amount brought out by the water flow is large.

2. Through the test of a plurality of (unmodified) samples of the severe saline-alkali soil of Wuyuan county of Bayan Teng, the samples mainly contain carbonate and bicarbonate. The participating experiments were A, B, C, F groups.

The group A experiment mode adopts a continuous drip irrigation or spraying mode (two modes have no influence on the experiment result) of a dilute nitric acid solution with the concentration of 0.005%, and the PH value of the soil is reduced to 8.7 from 10.3 before the experiment after quantitative continuous drip irrigation for 24 hours. The total salt content is not obviously reduced and is still 2.6 percent of the data before the experiment. And then, common water is adopted for continuous drip irrigation according to the period, during the experiment period, the water flow in the drainage process of the upper layer salt discharge pipe is in a continuous water drop shape, the lower layer water-blocking salt discharge pipe is in a fine water column shape due to the fact that the lower layer soil is soaked in the high-salt water body, and the connection between the water content of the lower layer soil and the upper layer soil is not obvious. The soil around the water-blocking salt discharge pipe is moist, and no obvious capillary pipe signs exist. After the experiment, the pH value of the upper soil layer is 8.1, and the total salt content is 2.1%. And the B group experiment mode adopts a continuous drip irrigation or spraying mode (two modes have no influence on the experiment result) of a dilute nitric acid solution with the concentration of 0.005%, and the PH value of the soil is reduced to 8.4 from 10.3 before the experiment after quantitative continuous drip irrigation for 24 hours. The total salt content is not obviously reduced and is still 2.6 percent of the data before the experiment. And during the experiment, the water flow in the drainage process of the upper-layer salt discharge pipe forms continuous water drop-shaped water volume smaller than that of the upper-layer salt discharge pipe of the group A, and the lower-layer water-blocking salt discharge pipe is in a thin water column shape because the lower-layer soil is soaked in the high-salt water body to discharge larger water volume, slightly increases the water volume compared with the group A, but is not obvious, and the water content of the lower-layer soil is connected with the upper-layer soil in a small scale. The soil around the water-blocking salt-removing pipe is moist, and no obvious capillary pipe sign exists. After the experiment, the pH value of the upper soil layer is 8.2, and the total salt content is 2.3%. The experimental results are compared to find that: the mode that no aperture is located at the bottom of the salt discharging pipe can effectively reduce the phenomenon that an upper-layer water system flows out during the water discharging period and enters a lower-layer water system, salt in soil can be discharged better, but added agents can also increase waste correspondingly, and waste applied in the crop dropping process can also be wasted to a certain extent in the same way.

And the comparison of the group C experiments shows that: and the water storage capacity of the group C is weaker than that of the group A, the watering frequency needs to be increased, and the water resource waste and the fertility are high.

And thirdly, the weak acid method is only suitable for saline-alkali soil mainly containing carbonate and bicarbonate, nitrate of the weak acid method is dissolved and discharged along with water, and the use of sulfuric acid or hydrochloric acid can increase soil sediments, increase soil hardening degree and be not beneficial to crop cultivation.

And fourthly, the pipe wall of the lower layer water-blocking salt-removing pipe is a full-aperture net pipe, so that underground water can be collected to form a water channel.

Controlling the liquid levels of the external Na2CO3 solution to be 15cm, 30cm and 75cm through an F group experimental device, wherein once the water level of the underground high-salinity water body approaches or reaches the height of the water-blocking salt-removing pipe, the efficiency of the soil salt-removing engineering is seriously reduced, and the effect of the upper-layer salt-removing pipe is not greatly influenced; when the height of the water-blocking salt discharge pipe is exceeded, the water discharge amount of the water-blocking salt discharge pipe is suddenly increased, the salt discharge system basically fails, the salt discharge concentration of the upper-layer salt discharge pipe is increased, and the salt transportation direction in the soil is upwards gathered along with the evaporation of the soil water on the earth surface, so that the actual effect of the whole soil salt discharge treatment is weakened. Experimental results show that the lower-layer water-blocking salt-discharging pipe plays an important role in river beaches or regions with higher groundwater levels, but in actual use, the local groundwater level should be paid attention to, and the burying depth should be arranged above the mean value of the groundwater level.

Sixthly, a large amount of soil flows out of each pipe diameter in the experiment.

3. The salt elimination experiment is carried out on the saline-alkali soil improved by the gypsum method. According to the basic principle of improving soil by a gypsum method, the improved soil can be hardenedThe degree is higher. The main theory of the gypsum method for treating the saline-alkali soil is CaSO₄+Na₂CO₃—＞CaCO³+Na₂SO₄，CaSO₄+NaHCO₃—＞Ca(HCO₃)₂+Na₂SO₄CaCO produced in this way₃Cannot be dissolved by the water seepage of the soil, and after the water is gradually deposited, the soil hardening degree is continuously deepened, which is not beneficial to the cultivation of crops. Through the experiment of group A, the diluted nitric acid solution with the concentration of 0.005% is adopted for continuous drip irrigation, and after the quantitative continuous drip irrigation is carried out for 24 hours (the dosage of the diluted nitric acid solution is different from that of the untreated soil), the PH value of the soil is reduced to 7.6 from the PH8.1 before the experiment, and the data before the full salt amount experiment is 1.3%. And then continuously carrying out drip irrigation for 720h by adopting common water according to the normal drip irrigation speed. After the experiment is finished, the PH value of the upper soil layer is 7.3, the total salt content is 0.9%, and the soil hardening degree is obviously reduced after the soil is dried. Through comparison before and after experiments, the method for treating the saline-alkali soil by using the desulfurized gypsum has the defect of soil hardening, and seriously influences the cultivation of a batch of crops such as potatoes, Chinese yams, sweet potatoes, peanuts and the like.

4. Waste water is collected and put into an electrochemical purification device, and the waste water can reach the standard of tap water after being filtered and subjected to electrochemical desalting and can be reused.

The water drawing holes on the salt discharge pipe network are distributed in a regular triangle staggered manner, so that the stress area of the pipe body is increased, and the water permeability is increased; the aperture sets up and is the hourglass hopper form from the external diameter to the pipe wall internal diameter through the test, the outer wall aperture generally sets up to 2cm, the inner wall aperture sets up to 1cm, aperture inner wall or the inside iron wire filter screen that presss from both sides of body, fill by the asbestos in the aperture, mainly play and filter silt anticorrosion, earth blocking effect in the reduction salt discharge pipe, salt discharge pipe life is arranged in very big extension, simultaneously to blocking water the salt discharge pipe play the guard action well at the formula drainage in-process that soaks entirely, to blocking water the intraduct of salt discharge when reducing a large amount of water.

The embodiments of the present invention have been described in detail above, but they are merely exemplary, and the present invention is not equivalent to the above described embodiments. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, it is intended that all equivalent alterations and modifications be included within the scope of the invention, without departing from the spirit and scope of the invention.

Claims

1. The water-saving saline-alkali land treating technology features that dilute nitric acid solution of 0.005% concentration is used to permeate soil for washing, and through two-stage concealed pipes, water controlling and salt eliminating are performed.

2. The saline-alkali soil water-saving treatment system based on claim 1 is characterized by comprising a salt discharge pipe network, a water channel, a lifting pump station and a purification facility, wherein the salt discharge pipe network is formed by two stages of concealed pipes;

the two-stage concealed pipes comprise an upper-layer salt discharge pipe and a lower-layer water-blocking salt discharge pipe, the upper-layer salt discharge pipe and the lower-layer water-blocking salt discharge pipe are connected through a connecting pipe, and a plurality of water drawing holes are formed in the surfaces of the upper-layer salt discharge pipe and the lower-layer water-blocking salt discharge pipe; the upper-layer salt discharge pipe comprises a branch pipe assembly and a water collection pipe, the branch pipe forms an included angle of 5 degrees with the vertical direction, and is bent into a vertically arranged straight pipe at an outlet and then is collected into the water collection pipe, and the number of the branch pipes and the number of the water collection pipes are multiple, so that a pipe network is formed; the tail ends of the water collecting pipe and the lower-layer water-blocking salt discharging pipe are communicated with the ditch.

3. The saline-alkali soil water-saving treatment system as claimed in claim 2, wherein the branched pipe adopts a PVC mesh salt discharge pipe with the diameter of 15-30cm, and is buried at the position 70-75cm away from the ground surface at the top of the pipe; the lower layer water-blocking salt-removing pipe adopts a cement product mesh water-blocking calandria, and a mesh pipe with the diameter of 75-150 cm is adopted according to the water level and water quantity of underground water in a region and is buried below the pipe top and 150cm away from the ground surface to a position above the average height of the ground surface water.

4. The saline-alkali soil water-saving treatment system as claimed in claim 2, wherein the interval of the branch pipes is 10-15m, and the interval of the lower-layer group water salt discharge pipe is 100-150 m.

5. The saline-alkali soil water-saving treatment system according to claim 2, wherein the straight pipe is 5cm in length.

6. The saline-alkali soil water-saving treatment system as claimed in claim 2, wherein the water drawing holes on the surface of the branch pipe are distributed in a regular triangle shape, the hole diameter of the water drawing holes is in an inverted funnel shape from the outer wall to the inner wall of the branch pipe, and an iron wire filter screen is arranged inside the water drawing holes or the water dividing pipe.

7. The saline-alkali soil water-saving treatment system as claimed in claim 6, wherein the diameter of the outer wall of the water suction hole is 2cm, and the diameter of the inner wall of the water suction hole is 1 cm.

8. The saline-alkali soil water-saving treatment system as claimed in claim 6, wherein asbestos is filled in the water drawing holes or the water dividing pipes.

9. The saline-alkali soil water-saving treatment system as claimed in claim 2, wherein the water catchment pipe and the lower layer water-blocking and salt-removing pipe are not provided with water drawing holes within 90 ° vertically downward with the inner diameter central point as the center.

10. The water-saving saline-alkali soil treatment system as claimed in claim 2, wherein the treatment system further comprises a reservoir, and a lifting pump station, a purification facility and four 100-inch reservoir 150m are arranged beside the ditch on the land with the standard of more than forty thousand mu³The water reservoir.