Decision-making method for variable rate irrigation management

Patent metadata

Field	Value
Publication number	US-11944048-B2
Application number	US-202117343748-A
Country	US
Kind code	B2
Filing date	Jun 10, 2021
Priority date	Mar 5, 2021
Publication date	Apr 2, 2024
Grant date	Apr 2, 2024

Abstract

A decision-making method for variable rate irrigation management includes the following steps: S1: sampling a soil from a root zone of a crop in an area controlled by an irrigation sprinkler, and measuring compositions of separates of the sampled soil; S2: managing and dividing the area controlled by the irrigation sprinkler according to an AWC of the soil in the root zone of the crop; S3: constructing an optimized soil moisture sensor network; S4: placing ground-fixed canopy temperature sensors; S5: constructing an optimized airborne canopy temperature sensor network centered on the center pivot; and S6: performing a variable rate irrigation by using the optimized soil moisture sensor network, the fixed canopy temperature sensors, the optimized airborne canopy temperature sensor network and an automatic weather station. The method optimizes the placement and quantity of the soil moisture sensor network and the canopy temperature sensor network to improve the measurement accuracy.

First claim

What is claimed is:

1. A decision-making method for a variable rate irrigation management, comprising the following steps:
S 1 : sampling a soil from a root zone of a crop in an area controlled by an irrigation sprinkler, and measuring compositions of separates of the soil;
S 2 : based on the separates of the soil, managing and dividing, according to an available water capacity (AWC) of the soil in the root zone of the crop, the area controlled by the irrigation sprinkler into a low-AWC management zone, a medium-AWC management zone and a high-AWC management zone;
S 3 : based on the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone, constructing an optimized soil moisture sensor network;
S 4 : placing ground-fixed canopy temperature sensors at positions of the high-AWC management zone, wherein soil moisture sensors are placed at the positions of the high-AWC management zone;
S 5 : constructing an optimized airborne canopy temperature sensor network centered on a center pivot of the irrigation sprinkler; and
S 6 : according to a canopy coverage obtained before and after the crop enters a jointing stage, performing a variable rate irrigation by using the optimized soil moisture sensor network, the ground-fixed canopy temperature sensors, the optimized airborne canopy temperature sensor network and an automatic weather station, respectively,
wherein
in step S 2 , the managing and dividing of the area controlled by the irrigation sprinkler comprises:
based on the separates of the soil, calculating the AWC of the soil in the root zone of the crop by using a Rosetta software, and performing a management and division on the AWC of the soil in the root zone of the crop by using a Jenks natural breaks classification method to obtain the low-AWC management zone, the medium-AWC management zone, and the high-AWC management zone.

2. The decision-making method according to claim 1 , wherein
in step S 1 , a method for sampling and measuring the soil comprises:
sampling by using a square grid method, and measuring the compositions of the separates of the soil with a root dry weight distribution of ≥80% by depths in the root zone of the crop in the area controlled by the irrigation sprinkler, wherein the separates of the soil comprise sand particles, silt particles and clay particles, and a number of square grids is greater than or equal to 100.

3. The decision-making method according to claim 1 , wherein
step S 3 comprises the following sub-steps:
S 31 : calculating an average clay content Clay in each of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone; and
S 32 : for each of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone, placing the soil moisture sensors at the positions each with 1.1-1.2 times the average clay content Clay to construct the optimized soil moisture sensor network.

4. The decision-making method according to claim 3 , wherein
in step S 31 , the average clay content Clay is calculated according to the following formula:

Clay
_

=

∑

i
=
1

n

Clay
i

;

wherein, n represents a number of grids contained in each of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone for measuring the compositions of the separates of the soil, and Clay i represents an average clay content of a soil in a root zone of a crop in an ith grid.

5. The decision-making method according to claim 1 , wherein
step S 5 comprises the following sub-steps:
S 51 : discretely creating concentric circles with different radii centered on the center pivot of the irrigation sprinkler;
S 52 : when a number of the concentric circles with circumferences intersecting with square grids is greater than or equal to 100, taking the number of the concentric circles as a minimum number of airborne canopy temperature sensors placed along a truss direction of the irrigation sprinkler; and
S 53 : according to the minimum number of the airborne canopy temperature sensors, constructing the optimized airborne canopy temperature sensor network.

6. The decision-making method according to claim 5 , wherein
in step S 53 , a method for constructing the optimized airborne canopy temperature sensor network comprises:
according to distances between the airborne canopy temperature sensors and the center pivot of the irrigation sprinkler, based on a principle that measurement data obtained from each of the airborne canopy temperature sensors represents an equal observation area, optimizing positions of the airborne canopy temperature sensors placed along the truss direction of the irrigation sprinkler; and
calculating a distance R m between an mth airborne canopy temperature sensor of the airborne canopy temperature sensors and the center pivot of the irrigation sprinkler according to the following formula:
R m =R ×√{square root over ( m )}/√{square root over ( X )};

wherein, R represents a radius of a circular area irrigated by the center pivot irrigation sprinkler, and X represents a number of the airborne canopy temperature sensors.

7. The decision-making method according to claim 1 , wherein
in step S 6 , if the crop has not entered the jointing stage, a method for monitoring soil moisture content data by using the optimized soil moisture sensor network and performing the variable rate irrigation specifically comprises:
performing the variable rate irrigation when a soil moisture content in one of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone reaches a set irrigation water lower limit, wherein a water amount for the variable rate irrigation is determined by a difference between an irrigation water upper limit and a measured soil moisture content in each of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone; and
if the crop has entered the jointing stage, performing the variable rate irrigation when the soil moisture content in one of the low-AWC management zone, the medium-AWC management zone and the high-AWC management zone reaches the set irrigation water lower limit; under semi-arid climate conditions, performing the variable rate irrigation by using the ground-fixed canopy temperature sensors, the optimized airborne canopy temperature sensor network and monitoring data obtained from the automatic weather station; and under semi-humid climate conditions, performing the variable rate irrigation by using the optimized soil moisture sensor network, the optimized airborne canopy temperature sensor network and the ground-fixed canopy temperature sensors.

8. The decision-making method according to claim 7 , wherein
in step S 6 , if the crop has entered the jointing stage, a method for performing the variable rate irrigation by using the ground-fixed canopy temperature sensors, the optimized airborne canopy temperature sensor network and the monitoring data obtained from the automatic weather station under the semi-arid climate conditions comprises:
A 61 : when the soil moisture content in one of the low-AWC management zone, the medium-AWC management zone and the high-AWC manag

Assignees

• China Inst Water Resources & Hydropower Res

Inventors

• Zhao Weixia
• Li Jiusheng
• Li Yanfeng
• Wang Zhen
• Wang Jun

Classifications

• A01G25/167 Primary

  Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors · CPC title

• A01G25/162

  Sequential operation · CPC title

• A01G25/165

  Cyclic operations, timing systems, timing valves, impulse operations · CPC title

• G01K1/026

  arrangements for monitoring a plurality of temperatures, e.g. by multiplexing · CPC title

• G01N33/246 Primary

  for water content · CPC title