CN115222152A - A method for optimizing the rotation irrigation system to improve the evenness of drip irrigation in the field - Google Patents

Abstract

The invention discloses a method for optimizing a wheel irrigation system for improving field drip irrigation uniformity, which is applied to the technical field of agricultural irrigation, and is characterized in that based on the traditional design achievement of drip irrigation engineering, the inlet pressure of each irrigation cell of a drip irrigation system is further calculated, the pressure and flow distribution range of the drippers of the irrigation cells are calculated, the actual irrigation time required by each wheel irrigation group corresponding to the irrigation cells is calculated on the basis of ensuring that the irrigation quota of each irrigation cell is consistent, so that the pressure and flow of each node of the drip irrigation system meet the design standard, the irrigation quota is close, the irrigation time can be reduced, the energy consumption is saved, the water resource utilization efficiency is improved, the irrigation uniformity is improved, the labor intensity of farmers is reduced, and a design method and a basis are provided for large-area upgrading of the drip irrigation system and automation and intellectualization later.

Description

A method for optimizing the rotation irrigation system to improve the evenness of drip irrigation in the field

technical field

The invention relates to the technical field of agricultural irrigation, in particular to a method for optimizing the rotation irrigation system for improving the evenness of drip irrigation in the field.

Background technique

Irrigation uniformity is an important indicator for evaluating irrigation quality, which mainly reflects the uniformity of the distribution of irrigation water, and is also one of the important parameters of drip irrigation engineering design. There are many factors that affect the uniformity of irrigation. In addition to the manufacturing deviation of the irrigator and the blockage of the irrigator, the uniformity of the irrigation will be affected. The terrain, the working conditions of the drip irrigation system, the structure of the pipe network, the irrigation system, and the temperature change of the irrigation water will affect the uniformity of the irrigation water. The change.

At present, the design of drip irrigation projects mainly follows the "Technical Specifications for Micro-Irrigation Engineering" (GB/T50485-2020). The pressure deviation of the irrigation community is controlled by limiting the flow deviation rate of the irrigation community to not less than 80%, so as to further ensure the uniform irrigation of the drip irrigation system. Spend. However, this standard does not give a quantitative standard for the flow deviation rate of the entire drip irrigation pipe network, so that although the field drip irrigation system with an irrigation scale of more than 1,000 mu can meet the flow deviation rate of the irrigation community, the flow deviation rate of the entire drip irrigation pipe network is 30%. -50%, the irrigation uniformity will decrease accordingly. The reduction of irrigation uniformity will not only affect the efficient use of water and fertilizer, but also affect the fairness of farmers' water use. The drip irrigation project design usually stipulates that the irrigation time of each irrigation area is the same, but when the actual project is running, at the same irrigation time, the inlet of the irrigation area close to the water source has high working pressure and uses more water; the irrigation area farthest from the water source will use more water. The inlet working pressure is small, and the amount of water used is small. This results in different amounts of water being distributed by farmers during the same irrigation time, which also reduces the uniformity of irrigation accordingly. Therefore, how to improve the irrigation uniformity of field drip irrigation and the fairness of farmers' water use is a problem that needs to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a method for optimizing the rotation irrigation system for improving the evenness of drip irrigation in the field, which can make the pressure and flow of each irrigation community meet the requirements of the "Micro-irrigation Engineering Technical Standards" (GB/T50485-2020) At the same time, the irrigation uniformity is higher, the irrigation time is shortened, the water resource utilization efficiency is further improved, and the system energy consumption is reduced, which can provide a new idea for the upgrading and transformation of high-standard farmland, so that the design results of the drip irrigation project are closer to the management needs of the drip irrigation project. It satisfies the fairness and timeliness of farmers' water use.

In order to achieve the above object, the present invention provides the following technical solutions:

A method for optimizing the rotation irrigation system for improving the evenness of drip irrigation in the field, comprising the following steps:

S1. Based on the traditional design of drip irrigation projects, calculate the inlet pressure of each irrigation area of the drip irrigation system;

S2, calculating the pressure range and flow range of the dripper in the irrigation community based on the inlet pressure of each irrigation community;

S3. Under the condition that the distance between the dripper and the capillary remains unchanged, ensure that the irrigation quota is unchanged, and calculate the irrigation time of each irrigation area based on the flow range of the dripper in the irrigation area;

S4, determining the irrigation time of each round of irrigation groups based on the irrigation time of each irrigation area, and optimizing the round irrigation system by controlling the irrigation time of each round of irrigation groups.

Preferably, after the step S4, the method further includes: S5, calculating the deviation of the irrigation quota, and reflecting the uniformity of the irrigation through the deviation of the irrigation quota.

Preferably, the S1 calculates the inlet pressure of each irrigation area of the drip irrigation system by the following formula:

h _nm =HZ _p +Z _b -∑h _{fnm -∑h inm}

In the formula, h _nm represents the working pressure at the inlet of the irrigation area on the m-th branch pipe on the nth branch pipe, H represents the system design head pressure, Z _p represents the elevation of the water inlet of the irrigation area pipe network, and Z _b represents the system The design water level of the water source, ∑h _fnm represents the water head loss along the pipeline from the inlet of the system to the inlet of the mth irrigation district on the nth branch pipe, _{∑h inm} represents the mth point from the system inlet to the nth branch trunk pipe The local head loss of the pipes and equipment at the entrance of each irrigation area, where H is specifically:

H=Z _p -Z _b +h ₀ +∑h _f +∑h _i

In the formula, h ₀ represents the working pressure at the inlet of a typical irrigation community, _{∑h f} represents the water head loss along the pipeline from the system inlet to the inlet of a typical irrigation community, and ∑hi represents the local head of the pipeline and equipment from the system inlet to the inlet of a typical irrigation community loss.

Preferably, the S2 calculates the dripper pressure by the following formula:

h _{dripper ij} = h _nm -h _{branch i} -h _{hair ij}

In the formula, h _{dripper ij} represents the inlet pressure of the jth dripper on the ith capillary tube, h _nm represents the working pressure of the irrigation cell inlet on the mth branch pipe on the nth branch pipe, and the h _{branch i} represents The pressure difference between the inlet of the ith capillary tube and the inlet of the branch tube, _hmaoij represents the pressure difference between the inlet of the jth dripper and the inlet of the ith capillary tube;

Calculate the dripper flow by:

In the formula, q _{dripper ij} represents the flow of the jth dripper on the i-th capillary, k is the flow coefficient, and x is the flow index. According to the range of the dripper inlet pressure in the irrigation area, the dripper flow of the irrigation area is calculated range.

Preferably, the S3 calculates the duration of one irrigation of the jth dripper on the ith capillary by the following formula:

t _ij =MS _e S _l /q _{dripper ij}

In the formula, t _ij represents the duration of one irrigation of the jth dripper on the ith capillary, M represents the design irrigation quota, q _{dripper ij} represents the flow rate of the jth dripper on the ith capillary, _Se is the drip head spacing, S _l is the capillary spacing;

Calculate the irrigation time of the irrigation area by the following formula:

t _nm = max(t ₁₁ , t ₁₂ , t ₁₃ …t _ij )

In the formula, t _nm represents the duration of one irrigation in the irrigation area corresponding to the mth branch pipe on the nth branch pipe.

Preferably, the S4 is specifically: taking the irrigation time required by the irrigation cell with the longest irrigation duration in a rotation irrigation group as the irrigation time t' _nm of the rotation irrigation group.

Preferably, the S5 adopts the following formula to calculate the irrigation quota deviation:

In the formula, M _v represents the irrigation quota deviation, M _d represents the maximum net irrigation quota, M _max is the maximum irrigation quota in the pipe network, and M _min is the minimum irrigation quota in the pipe network, where:

M _d =γzρ(θ _max -θ _min )

表示在整个管网中，第n条分干管、第m条支管，第i条毛管、第j个滴头在一次灌水延续时间内的实际灌水定额。In the formula, γ is the soil capacity, z is the depth of the planned soil wetting layer, ρ is the design soil wetting ratio, θ _max is the upper limit of the suitable soil moisture content, θ _min is the lower limit of the suitable soil moisture content, q _{drip tip ij} represents the i-th capillary The flow rate of the jth dripper above, t' _nm is the irrigation time of the rotation irrigation group, Se is the _dripper spacing, S _l is the capillary spacing,

Indicates the actual irrigation quota of the nth branch pipe, the mth branch pipe, the ith capillary pipe, and the jth dripper in the duration of one irrigation in the entire pipe network.

It can be seen from the above technical solutions that, compared with the prior art, the present invention provides a method for optimizing the irrigation system for improving the water uniformity of drip irrigation in the field, so that the pressure and flow of each node of the drip irrigation system meet the design standards and the irrigation water can be improved. The quota is close, which can reduce the irrigation time, save energy consumption, improve the efficiency of water resources utilization, improve the uniformity of irrigation, and reduce the labor intensity of farmers.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to the provided drawings without creative work.

Fig. 1 is the method flow chart of the present invention;

2 is a schematic diagram of the inlet pressure of each irrigation cell in an embodiment of the present invention;

3 is a schematic diagram of the pressure-flow range of the dripper of each irrigation cell in an embodiment of the present invention;

FIG. 4 is a schematic diagram of the irrigation time range of each irrigation cell in an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The embodiment of the present invention discloses a method for optimizing the rotation irrigation system for improving the evenness of drip irrigation in the field. As shown in FIG. 1 , the method includes the following steps:

S1. Based on the traditional design of drip irrigation projects, calculate the inlet pressure of each irrigation area of the drip irrigation system;

S2. Calculate the pressure range and flow range of the dripper in the irrigation area based on the inlet pressure of each irrigation area;

S3. Under the condition that the distance between the dripper and the capillary remains unchanged, ensure that the irrigation quota is unchanged, and calculate the irrigation time of each irrigation area based on the flow range of the dripper in the irrigation area;

S4, determining the irrigation time of each round of irrigation groups based on the irrigation time of each irrigation area, and optimizing the round irrigation system by controlling the irrigation time of each round of irrigation groups.

It should be understood that the irrigation range controlled by a branch pipe in the irrigation pipe network is one irrigation area, and a rotation irrigation group includes multiple irrigation areas.

In another embodiment of the present invention, S1 calculates the inlet pressure of each irrigation cell of the drip irrigation system by the following formula:

h _nm =HZ _p +Z _b -∑h _{fnm -∑h inm}

In the formula, h _nm represents the working pressure at the inlet of the irrigation community on the mth branch pipe on the nth branch pipe, H represents the system design head pressure, Z _p represents the elevation of the water inlet of the irrigation campus pipe network, and Z _b represents the system The design water level of the water source, ∑h _fnm represents the water head loss along the pipeline from the inlet of the system to the inlet of the mth irrigation district on the nth branch pipe, _{∑h inm} represents the mth point from the system inlet to the nth branch trunk pipe The local water head loss of the pipelines and equipment at the entrance of each irrigation community needs to be understood that when the drip irrigation system is actually running, the pump head is usually greater than or equal to the design head H, and the water is supplied to each irrigation group at a relatively stable head, which leads to other When the rotation irrigation group is running, the working pressure at the inlet of the irrigation area is different due to the distance from the water source and the difference in terrain height. Therefore, the above formula is used to calculate the working pressure at the inlet of the irrigation area.

Where H is specifically:

H=Z _p -Z _b +h ₀ +∑h _f +∑h _i

In the formula, h ₀ represents the working pressure at the inlet of a typical irrigation cell, including the pressure water head consumed by auxiliary facilities such as cell filtration and fertilization (medicine). ∑h _f represents the water head loss along the pipeline from the inlet of the system to the inlet of a typical irrigation area, including the head loss along the way of the first hub. _∑hi represents the local head loss of the pipelines and equipment from the system inlet to the inlet of a typical irrigation community, including the local head loss of the head hub.

In another embodiment of the present invention, S2 calculates the dripper pressure by the following formula:

h _{dripper ij} = h _nm -h _{branch i} -h _{hair ij}

In the formula, h _{dripper ij} represents the inlet pressure of the jth dripper on the ith capillary tube, h _nm represents the working pressure of the irrigation cell inlet on the mth branch pipe on the nth branch pipe, and the h _{branch i} represents The pressure difference between the inlet of the i-th capillary tube and the inlet of the branch tube, _hmaoij represents the pressure difference between the inlet of the j-th dripper and the inlet of the i-th capillary tube; it should be understood that due to the different distances between the irrigation cells and the water source, the The influence of water head loss, local water head loss and terrain height difference is also different, which leads to different inlet pressures of each irrigation area. The above formula calculates the working pressure range of the dripper in each irrigation area;

Calculate the dripper flow by:

In the formula, q _{dripper ij} represents the flow of the jth dripper on the i-th capillary, k is the flow coefficient, and x is the flow index. According to the range of the dripper inlet pressure in the irrigation area, the dripper flow of the irrigation area is calculated range.

In another embodiment of the present invention, S3 calculates the duration of one irrigation of the jth dripper on the ith capillary by the following formula:

t _ij =M'S _e S _l /q _{dripper ij}

In the formula, t _ij represents the duration of one irrigation of the j-th dripper on the ith capillary, M' represents the design irrigation quota, q _{dripper ij} represents the flow rate of the j-th dripper on the ith capillary, and _Se is Dripper spacing, S _l is the capillary spacing;

Calculate the irrigation time of the irrigation area by the following formula:

t _nm = max(t ₁₁ , t ₁₂ , t ₁₃ …t _ij )

In the formula, t _nm represents the duration of one irrigation in the irrigation area corresponding to the mth branch pipe on the nth branch pipe. It should be understood that the irrigation time range of each irrigation area is calculated separately under the condition that the distance between the dripper and the capillary remains unchanged. Since there is only one ball valve at the inlet of a branch pipe to control the capillary water supply of the irrigation area, in order to meet the management requirements, the capillary irrigation time of the irrigation area should be consistent, and t _nm should be taken as the maximum value within the range. The actual calculation can also simplify the calculation process. The irrigation time required for the dripper farthest from the inlet of the branch pipe is t _nm .

In another embodiment of the present invention, S4 is specifically: taking the irrigation time required by the irrigation cell with the longest irrigation duration in a rotation irrigation group as the irrigation time t' _nm of the rotation irrigation group. For the convenience of management, the irrigation time of a rotation irrigation group should be consistent, so the irrigation time of the rotation irrigation group should take the maximum value of the irrigation time required in these irrigation cells. The irrigation time of the irrigation area corresponding to 1, 2 and 3 branches is: t ₁₁ , t ₁₂ , t ₁₃ , then the irrigation time of this round of irrigation group is t' _nm = max(t ₁₁ , t ₁₂ ,t ₁₃ ,).

In another embodiment of the present invention, after S4, it also includes: S5, calculating the irrigation quota deviation, and reflecting the irrigation uniformity through the irrigation quota deviation; it should be understood that the irrigation uniformity refers to the field irrigation water after the irrigation water wets the crop root soil The uniformity of the area, the drip irrigation system design is the preliminary work of the drip irrigation project construction, operation and management, and it is impossible to accurately predict the uniformity after the implementation of the project. Therefore, by controlling the flow deviation rate of the irrigation area to meet the requirements of the uniformity of irrigation, its essence It is to control the total amount of irrigation water within the duration of one irrigation in each irrigation area, that is, to control the irrigation quota. However, in the traditional design, the duration of one-time irrigation in each irrigation area is the same, but the flow rate is different, resulting in a large difference in the irrigation quota of each irrigation area. By optimizing the irrigation time of each round of irrigation groups, the deviation of the irrigation quota is reduced. , thereby improving the uniformity of irrigation.

Further, S5 uses the following formula to calculate the irrigation quota deviation:

In the formula, M _v represents the irrigation quota deviation, M _d represents the maximum net irrigation quota, M _max is the maximum irrigation quota in the pipe network, and M _min is the minimum irrigation quota in the pipe network, where:

M _d =γzρ(θ _max -θ _min )

表示在整个管网中，第n条分干管、第m条支管，第i条毛管、第j个滴头在一次灌水延续时间内的实际灌水定额。In the formula, γ is the soil capacity, z is the depth of the planned soil wetting layer, ρ is the design soil wetting ratio, θ _max is the upper limit of the suitable soil moisture content, θ _min is the lower limit of the suitable soil moisture content, q _{drip tip ij} represents the i-th capillary The flow rate of the jth dripper above, t' _nm is the irrigation time of the rotation irrigation group, Se is the _dripper spacing, S _l is the capillary spacing,

Indicates the actual irrigation quota of the nth branch pipe, the mth branch pipe, the ith capillary pipe, and the jth dripper in the duration of one irrigation in the entire pipe network.

In another embodiment of the present invention, a drip irrigation system designed according to a traditional drip irrigation design method is optimized. The diameter of the OA section of the main pipe of the system is 250mm, the main pipe is 250mm, and the other branches are 200mm and branch pipes. The diameter of the capillary tube is 110mm and the diameter of the capillary tube is 16mm. The main design parameters are shown in Table 1. The drip irrigation system in this embodiment has a total of 70 branch pipes to work, and the flow rate of each branch pipe is 66.15m ³ /h. There are 20 round irrigation groups. Each rotation irrigation group has 4 pipes to work, each working time is 5.01 hours, and the irrigation period is 6 days. In order to meet the requirements of farmers, the rotation irrigation system before and after the optimization in this embodiment is the same except for the rotation irrigation time, other parameters are the same, and the centralized rotation irrigation group is adopted. The specific rotation irrigation scheme is shown in Table 2. In this embodiment, the inlet pressure of each irrigation area is shown in Figure 2. In the figure, the water pressure elevation of irrigation area A5 is 393.42m, the ground elevation is 377.7m, and the pressure head is 15.72m. In this embodiment, the inlet pressure-flow rate of each irrigation area is The range is shown in Figure 3. The flow range of the dripper in the irrigation area A5 in the figure is 2.39-2.68m ³ /h, and the pressure range of the dripper is 12.89-15.69m; the irrigation time range of each irrigation area in this embodiment is shown in Figure 4 , the irrigation time range of the irrigation plot A5 in the figure is 3.36-3.77h.

Table 1 Main design parameters of drip irrigation project

Table 2. Rotational irrigation group schedule before and after optimization

It can be seen from Table 1 that the theoretical maximum irrigation quota of each irrigation community is 33.38mm (22.2m ³ /mu), the capillary spacing is 90cm, and the dripper spacing is 30cm. The deviation of the irrigation quota is obtained by calculation, and the optimization results are compared in Table 3.

Table 3. Comparison of case optimization results:

As can be seen from Table 3, after the optimization method is adopted in this embodiment, the drip irrigation system can shorten the irrigation time by about 14 hours, reduce the energy consumption by 19%, improve the water resource utilization efficiency by about 15%, and reduce the pipe network The overall irrigation quota deviation rate was 37%, the irrigation uniformity was significantly improved, and the labor intensity of farmers was also reduced.

The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. As for the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. A rotation irrigation system optimization method for improving field drip irrigation uniformity is characterized by comprising the following steps:

s1, calculating the inlet pressure of each irrigation cell of a drip irrigation system based on the traditional design of a drip irrigation project;

s2, calculating the pressure range and the flow range of the drippers of the irrigation community based on the inlet pressure of each irrigation community;

s3, under the condition that the dripper distance and the capillary distance are not changed, ensuring that the irrigation quota is not changed, and respectively calculating the irrigation time of each irrigation cell based on the dripper flow range of the irrigation cell;

and S4, determining the irrigation time of each rotation group based on the irrigation time of each irrigation cell, and optimizing the rotation system by controlling the irrigation time of each rotation group.

2. The method for optimizing a rotation system for improving field drip irrigation uniformity according to claim 1, wherein the step S4 is followed by the step of: and S5, calculating the irrigation quota deviation, and reflecting the irrigation uniformity through the irrigation quota deviation.

3. The optimization method of the rotation regime for improving the irrigation uniformity of the field drip irrigation according to claim 1, wherein the S1 is used for calculating the inlet pressure of each irrigation cell of the drip irrigation system according to the following formula:

h _nm ＝H-Z _p +Z _b -∑h _fnm -∑h _inm

in the formula, h _nm The working pressure of the inlet of the irrigation district on the mth branch pipe on the nth branch pipe is shown, H is the designed water head pressure of the system, Z _p Indicates the height, Z, of the water inlet of the pipe network of the irrigation school zone _b Represents the design water level of the system water source, sigma h _fnm Represents the water head loss on the way of the pipeline from the inlet of the system to the inlet of the mth irrigation small area on the nth main branch pipe, sigma h _inm And (3) local head loss of a pipeline and equipment from a system inlet to an mth irrigation cell inlet on the nth main branch pipe is represented, wherein H specifically is as follows:

H＝Z _p -Z _b +h ₀ +∑h _f +∑h _i

in the formula, h ₀ Represents the working pressure, Σ h, of the inlet of a typical irrigation district _f Represents the head loss on the way of the pipeline from the system inlet to the inlet of a typical irrigation district, sigma h _i Representing the local head loss of piping and equipment from the system inlet to the inlet of a typical watering cell.

4. The optimization method of the rotation irrigation system for improving the irrigation uniformity of the field drip irrigation according to claim 1, wherein the S2 is used for calculating the pressure of the drippers according to the following formula:

h _{dripper ij} ＝h _nm -h _{Zhi i} -h _{Hair ij}

In the formula, h _{Dripper ij} Represents the j-th dripper inlet pressure on the ith capillary, h _nm Denotes the number n on the nth divided pipeWorking pressure of inlet of irrigation district on m branch pipes, h _{Zhi i} Represents the pressure difference between the inlet of the ith capillary and the inlet of the branch pipe, h _{Hair ij} The pressure difference from the jth dripper inlet to the ith capillary inlet is shown;

the dripper flow is calculated by:

in the formula, q _{Dripper ij} And (3) representing the flow of the jth dripper on the ith capillary, wherein k is a flow coefficient, x is a flow state index, and the range of the flow of the dripper in the irrigation cell is calculated according to the range of the inlet pressure of the dripper in the irrigation cell.

5. The optimization method of the rotation irrigation system for improving the uniformity of field drip irrigation according to claim 1, wherein the S3 calculates the duration of the first irrigation of the jth emitter on the ith capillary according to the following formula:

t _ij ＝MS _e S _l /q _{dripper ij}

In the formula, t _ij Showing the duration of primary irrigation of the jth dripper on the ith capillary, M showing the designed irrigation quota, and q _{Dripper ij} Showing the flow of the jth dripper on the ith capillary, S _e Is the dripper spacing, S _l The distance between the capillary tubes;

calculating the watering time of the watering cell by the following formula:

t _nm ＝max(t ₁₁ ,t ₁₂ ,t ₁₃ …t _ij )

in the formula, t _nm And the duration of primary irrigation of the irrigation district corresponding to the mth branch pipe on the nth branch pipe is represented.

6. The optimization method of the rotation irrigation system for improving the field drip irrigation uniformity according to claim 1, wherein the step S4 specifically comprises: taking the irrigation time required by the irrigation cell with the maximum irrigation duration in one rotation irrigation group as the rotation irrigation groupIs water filling time t' _nm 。

7. The optimization method of the rotation irrigation system for improving the irrigation uniformity of the field drip irrigation according to claim 2, wherein the irrigation quota deviation is calculated by the following formula in S5:

in the formula, M _v Indicating deviation of water filling quota, M _d Denotes the maximum net irrigation quota, M _max For maximum water rating in the pipe network, M _min For minimum irrigation quota in the pipe network, wherein:

M _d ＝γzρ(θ _max -θ _min )

wherein gamma is the soil capacity, z is the planned wetting layer depth of the soil, rho is the designed soil wetting ratio, theta _max To suit the upper limit of the water content of the soil, theta _min Lower limit of water content of suitable soil q _{Dripper ij} Denotes the flow rate, t ', of the jth dripper on the ith capillary' _nm Time of irrigation for the rotation irrigation set, S _e Is the dripper spacing, S _l The distance between the capillary tubes is equal to the distance between the capillary tubes,

the nth branch pipe, the mth branch pipe and the mth branch pipe in the whole pipe networkThe actual irrigation quota of the i capillary and the j-th dripper within the duration of one irrigation.

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