CN103493693B - Furrow irrigates the defining method of suitable ditch, ridge ratio - Google Patents

Abstract

The invention provides the defining method that a kind of furrow irrigates suitable ditch, ridge ratio, comprise step: step 1: initialization step; Step 2: the wetting body values for spatial distribution and actual soil moisture content values for spatial distribution of infiltrating of pouring water obtaining different row spacing simulated scenario; Step 3: furrow Irrigation Infiltration wetting body is carried out spatial discretization, with plant growth to the requirement of root region soil moisture for target water content, according to the Euclidean distance between the actual soil moisture content in crop root zone in the different row spacing simulated scenario of Euclidean distance formulae discovery and target soil water cut; Step 4: the actual lateral infiltration distance determining different row spacing simulated scenario; Step 5: comprehensively take into account that to obtain row spacing comparatively suitable.The present invention is when known soil water property, farming technique parameter, and only need be calculated by numerical simulation and model, just can obtain furrow and irrigate suitable ditch, ridge ratio, without the need to carrying out field test, defining method is easy.

Description

Furrow irrigates the defining method of suitable ditch, ridge ratio

Technical field

The present invention relates to Agricultural Water-Soil Engineering field, particularly, relate to the defining method that furrow irrigates suitable ditch, ridge ratio.

Background technology

It is on ridge culture trench sowing plantation basis that furrow is irrigated, and being formed wide " furrow structure ", utilizing irrigation ditch water delivery and by the effect of soil hollow billet power, making moisture side be seeped into the ground irrigation method of wide ridge growth belt by changing ground micro-terrain.It is only irrigated long-term cropping in ditch, and relies on soil moisture side to ooze to realize the distribution of moisture between ridge, ditch, meet the crop water requirement of ditch, each growth belt in ridge, is that technology is oozed in the side of pouring water produced with agricultural structure adjustment.

The determination of the suitable ditch of furrow irrigation, ridge ratio is extremely important, and rational field ditch, ridge significantly improve than regular meeting pour water efficiency and uniformity coefficient, improve Crop Water Use Efficiency simultaneously, save agricultural water.Ridge is wide, pours water after terminating, and moisture is failed side and is seeped into ridge body, and on ridge, soil moisture is deficient, and soil water supply ability is low, and plant growth is impaired, and output reduces, and even occurs here withering.Ridge is narrow, and after pouring water, the very fast side of moisture is seeped into ridge body, and interfered infiltration phenomenon occurs, and causes irrigation water deep percolation serious, reduces utilization ratio of pouring water.Therefore need to determine that furrow irrigates suitable ditch, ridge ratio, to improve quality of pouring water, optimize field farming technique parameter, provide theories integration for having to promote between furrow sewage farming under long-term cropping condition, raising furrow irrigation technique level is had important practical significance.

Summary of the invention

For defect of the prior art, the object of this invention is to provide the defining method that a kind of furrow irrigates suitable ditch, ridge ratio.

Irrigate the defining method of suitable ditch, ridge ratio according to furrow provided by the invention, comprise the steps:

Step 1: initialization step: the different row spacing simulated scenario that setting furrow is irrigated; Obtain furrow irrigation soils Soil Water Movement Parameter; Determine furrow irrigation farming technical parameter, farming technique parameter comprises the high and limit, ridge in the depth of water in ditch bottom width, ditch, ridge and bottom of trench angle; And set crop irrigation quantity;

Step 2: according to starting condition and the boundary condition of furrow irrigation farming technical parameter determination furrow irrigation soils Infiltration, furrow irrigation soils Soil Water Movement Parameter in step 1 is updated to furrow irrigation soils moisture movement equation, namely, in formula (1), the golden finite element numerical of gal the Liao Dynasty is carried out to formula (1) and solves; On the crop irrigation quantity basis of setting, obtain the wetting body values for spatial distribution and actual soil moisture content values for spatial distribution of infiltrating of pouring water of different row spacing simulated scenario, wherein, formula (1) is:

$\frac{\∂\mathrm{\θ}}{\∂t}=\frac{\∂}{\∂x}\left(K\left(h\right)\frac{\∂h}{\∂x}\right)+\frac{\∂}{\∂z}\left(K\left(h\right)\frac{\∂h}{\∂z}\right)+\frac{\∂K\left(h\right)}{\∂z}$ Formula (1)

Wherein, θ is soil volumetric water content, unit cm ³/ cm ³, h is matric potential, and unit cm, t are the time of infiltrating, and unit min, K (h) are unsaturated hydraulic conductivities, and unit cm/min, x are horizontal ordinates, and unit cm, z are vertical coordinates, unit cm;

Step 3: furrow Irrigation Infiltration wetting body is carried out spatial discretization, with plant growth to the requirement of root region soil moisture for target water content, according to Euclidean distance formula, i.e. formula (2), calculates the Euclidean distance d between the actual soil moisture content in crop root zone in different row spacing simulated scenario and target soil water cut _ij:

${d_{\mathrm{ij}}}^2={\left(\underset{k=1}{\overset{m}{\mathrm{\Σ}}}{|{\mathrm{\θ}}_{\mathrm{ik}}-{\mathrm{\θ}}_{\mathrm{jk}}|}^2\right)}^{1/2}$ Formula (2)

Wherein, d _ijfor Euclidean distance, θ _ikfor treating judgment value, namely refer to the actual soil moisture content values for spatial distribution of certain row spacing simulated scenario, θ _jkfor desired value, namely refer to that plant growth is to the target water content values for spatial distribution required by root region soil moisture, k=1 ... m is furrow Irrigation Infiltration wetting body spatial spreading number;

Step 4: the wetting body values for spatial distribution of infiltrating according to pouring water in described step 2 obtains the wetting body lateral infiltration distance of different row spacing simulated scenario, with horizontal wetting front front end and occur interfered infiltration for boundary, determine the actual lateral infiltration distance of different row spacing simulated scenario;

Step 5: drop on the row spacing simulated scenario in the zone of reasonableness of setting from corresponding actual lateral infiltration distance, choose the minimum value in the Euclidean distance corresponding to these row spacing simulated scenario between the actual soil moisture content in crop root zone and target soil water cut, judge whether this minimum value is less than reasonable threshold value, further:

This minimum value of-Ruo is less than reasonable threshold value, then the row spacing determination furrow in the row spacing simulated scenario corresponding to this minimum value irrigates suitable ditch, ridge ratio;

This minimum value of-Ruo is more than or equal to reasonable threshold value, then reduce monopolization scope, returns step 1 and carries out initialization.

Preferably, adopt HYDRUS-2D simulation softward to carry out the golden finite element numerical of gal the Liao Dynasty to formula (1) to solve.

Preferably, the starting condition that furrow irrigation soils moisture movement infiltrates is initial soil moisture content.

Preferably, the boundary condition that furrow irrigation soils moisture movement infiltrates is: during furrow Irrigation Infiltration, in ditch, in ridge, position is axis of symmetry, is zero logical border, only considers the water infiltration process of 1/2 furrow specification section; Bottom of trench water-carrying section is for determine head condition; In infiltration process, ridge body covers and does not consider that Influence of Evaporation is zero flux border; Connect the border of two zero logical lower ends, border for infiltration border.

Compared with prior art, the present invention is when known soil water property, farming technique parameter, and only need be calculated by numerical simulation and model, just can obtain furrow and irrigate suitable ditch, ridge ratio, without the need to carrying out field test, defining method is easy.

Accompanying drawing explanation

By reading the detailed description done non-limiting example with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:

Fig. 1 is principle schematic of the present invention;

Fig. 2 is the furrow specification boundary graph described by furrow irrigation farming technical parameter.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.Following examples will contribute to those skilled in the art and understand the present invention further, but not limit the present invention in any form.It should be pointed out that to those skilled in the art, without departing from the inventive concept of the premise, some distortion and improvement can also be made.These all belong to protection scope of the present invention.

Irrigate the defining method of suitable ditch, ridge ratio according to furrow provided by the invention, comprise the steps:

Step 1: initialization step: the different row spacing simulated scenario that setting furrow is irrigated; Obtain furrow irrigation soils Soil Water Movement Parameter; Determine furrow irrigation farming technical parameter, farming technique parameter comprises the high and limit, ridge in the depth of water in ditch bottom width, ditch, ridge and bottom of trench angle; And set crop irrigation quantity.

Step 2: furrow irrigation soils moisture movement equation is as follows:

$\frac{\∂\mathrm{\θ}}{\∂t}=\frac{\∂}{\∂x}\left(K\left(h\right)\frac{\∂h}{\∂x}\right)+\frac{\∂}{\∂z}\left(K\left(h\right)\frac{\∂h}{\∂z}\right)+\frac{\∂K\left(h\right)}{\∂z}---\left(1\right)$

In formula, θ is soil volumetric water content, unit cm ³/ cm ³, h is matric potential, and unit cm, t are the time of infiltrating, and unit min, K (h) are unsaturated hydraulic conductivities, and unit cm/min, x are horizontal ordinates, and unit cm, z are vertical coordinates, unit cm.

The furrow specification boundary graph described by furrow irrigation farming technical parameter as shown in Figure 2.According to starting condition and the boundary condition of furrow irrigation farming technical parameter determination furrow irrigation soils Infiltration, initial and boundary condition as shown in Figure 2; The starting condition that furrow irrigation soils moisture movement infiltrates is initial soil moisture content.The boundary condition that furrow irrigation soils moisture movement infiltrates is: during furrow Irrigation Infiltration, in ditch, in (AB), ridge, (CD) position is axis of symmetry, is zero logical border, only considers the water infiltration process of 1/2 furrow specification section; Bottom of trench water-carrying section (AGF) is for determine head condition; In infiltration process, ridge body covering (EF, ED) does not consider that Influence of Evaporation is zero flux border; Connect the boundary B C of two zero logical lower ends, border for infiltration border.

The furrow irrigation soils Soil Water Movement Parameter of step 1 is updated to furrow irrigation soils moisture movement equation, i.e. formula (1), adopts HYDRUS-2D simulation softward to carry out the golden finite element numerical of gal the Liao Dynasty to formula (1) and solve; On the crop irrigation quantity basis of setting, obtain the wetting body values for spatial distribution and actual soil moisture content values for spatial distribution of infiltrating of pouring water of different row spacing simulated scenario.

Step 3: furrow Irrigation Infiltration wetting body is carried out spatial discretization, with plant growth to the requirement of root region soil moisture for target water content, according to Euclidean distance formula, i.e. formula (2), calculates the Euclidean distance d between the actual soil moisture content in crop root zone in different row spacing simulated scenario and target soil water cut _ij:

${d_{\mathrm{ij}}}^2={\left(\underset{k=1}{\overset{m}{\mathrm{\Σ}}}{|{\mathrm{\θ}}_{\mathrm{ik}}-{\mathrm{\θ}}_{\mathrm{jk}}|}^2\right)}^{1/2}---\left(2\right)$

D in formula _ijfor Euclidean distance, θ _ikfor treating judgment value, namely refer to the actual soil moisture content values for spatial distribution of certain row spacing simulated scenario, θ _jkfor desired value, namely refer to that plant growth is to the target water content values for spatial distribution required by root region soil moisture, k=1 ... m is furrow Irrigation Infiltration wetting body spatial spreading number.Euclidean distance is less, show actual soil moisture content and the mutual matching degree of target soil water cut good.

Step 4: the wetting body values for spatial distribution of infiltrating according to pouring water in described step 2 obtains the wetting body lateral infiltration distance of different row spacing simulated scenario, with horizontal wetting front front end and occur interfered infiltration for boundary, determine the actual lateral infiltration distance of different row spacing simulated scenario.

Step 5: comprehensively take into account the Euclidean distance in different row spacing simulated scenario between the actual soil moisture content in crop root zone and target soil water cut and actual lateral infiltration Distance Judgment standard, Euclidean distance under certain row spacing is less, and distance is oozed rationally in the side of this row spacing, this row spacing is comparatively suitable accordingly.Otherwise constantly row spacing scope is reduced in adjustment, repeats above-mentioned steps, finally determine that furrow irrigates suitable ditch, ridge ratio.

Particularly, drop on the row spacing simulated scenario in the zone of reasonableness of setting from corresponding actual lateral infiltration distance, choose the minimum value in the Euclidean distance corresponding to these row spacing simulated scenario between the actual soil moisture content in crop root zone and target soil water cut, judge whether this minimum value is less than reasonable threshold value, further:

This minimum value of-Ruo is less than reasonable threshold value, then the row spacing determination furrow in the row spacing simulated scenario corresponding to this minimum value irrigates suitable ditch, ridge ratio;

This minimum value of-Ruo is more than or equal to reasonable threshold value, then reduce monopolization scope, returns step 1 and carries out initialization.

Above specific embodiments of the invention are described.It is to be appreciated that the present invention is not limited to above-mentioned particular implementation, those skilled in the art can make various distortion or amendment within the scope of the claims, and this does not affect flesh and blood of the present invention.

Claims (2)

1. furrow irrigates a defining method for suitable ditch, ridge ratio, it is characterized in that, comprises the steps:

Step 1: initialization step: the different row spacing simulated scenario that setting furrow is irrigated; Obtain furrow irrigation soils Soil Water Movement Parameter; Determine furrow irrigation farming technical parameter, farming technique parameter comprises the high and limit, ridge in the depth of water in ditch bottom width, ditch, ridge and bottom of trench angle; And set crop irrigation quantity;

Step 2: according to starting condition and the boundary condition of furrow irrigation farming technical parameter determination furrow irrigation soils Infiltration, furrow irrigation soils Soil Water Movement Parameter in step 1 is updated to furrow irrigation soils moisture movement equation, namely in formula (1), carry out the golden finite element numerical of gal the Liao Dynasty to formula (1) to solve, on the crop irrigation quantity basis of setting, obtain the wetting body values for spatial distribution and actual soil moisture content values for spatial distribution of infiltrating of pouring water of different row spacing simulated scenario, wherein, formula (1) is:

formula (1)

Wherein, θ is soil volumetric water content, unit cm ³/ cm ³, h is matric potential, and unit cm, t are the time of infiltrating, and unit min, K (h) are unsaturated hydraulic conductivities, and unit cm/min, x are horizontal ordinates, and unit cm, z are vertical coordinates, unit cm;

Step 3: furrow Irrigation Infiltration wetting body is carried out spatial discretization, with plant growth to the requirement of root region soil moisture for target water content, according to Euclidean distance formula, i.e. formula (2), calculates the Euclidean distance d between the actual soil moisture content in crop root zone in different row spacing simulated scenario and target soil water cut _ij:

formula (2)

Wherein, d _ijfor Euclidean distance, θ _ikfor treating judgment value, namely refer to the actual soil moisture content values for spatial distribution of certain row spacing simulated scenario, θ _jkfor desired value, namely refer to that plant growth is to the target water content values for spatial distribution required by root region soil moisture, k=1 ... m is furrow Irrigation Infiltration wetting body spatial spreading number;

Step 4: the wetting body values for spatial distribution of infiltrating according to pouring water in described step 2 obtains the wetting body lateral infiltration distance of different row spacing simulated scenario, there is interfered infiltration for boundary with horizontal wetting front front end, determine the actual lateral infiltration distance of different row spacing simulated scenario;

Step 5: drop on the row spacing simulated scenario in the zone of reasonableness of setting from corresponding actual lateral infiltration distance, choose the minimum value in the Euclidean distance corresponding to these row spacing simulated scenario between the actual soil moisture content in crop root zone and target soil water cut, judge whether this minimum value is less than reasonable threshold value, further:

This minimum value of-Ruo is less than reasonable threshold value, then the row spacing determination furrow in the row spacing simulated scenario corresponding to this minimum value irrigates suitable ditch, ridge ratio;

This minimum value of-Ruo is more than or equal to reasonable threshold value, then reduce monopolization scope, returns step 1 and carries out initialization;

The starting condition that furrow irrigation soils moisture movement infiltrates is initial soil moisture content;

The boundary condition that furrow irrigation soils moisture movement infiltrates is: during furrow Irrigation Infiltration, in ditch, in ridge, position is axis of symmetry, is zero logical border, only considers the water infiltration process of 1/2 furrow specification section; Bottom of trench water-carrying section is for determine head condition; In infiltration process, ridge body covers and does not consider that Influence of Evaporation is zero flux border; Connect the border of two zero logical lower ends, border for infiltration border.

2. furrow according to claim 1 irrigates the defining method of suitable ditch, ridge ratio, it is characterized in that, adopts HYDRUS-2D simulation softward to carry out the golden finite element numerical of gal the Liao Dynasty to formula (1) and solves.