Method for calculating summer corn actual crop coefficient based on weather and biological factors

A technology of biological factors and meteorological factors, applied in the field of agricultural assessment, can solve problems such as deviation of evapotranspiration

Inactive Publication Date: 2020-04-28
安徽省(水利部淮河水利委员会)水利科学研究院(安徽省水利工程质量检测中心站)
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AI Technical Summary

Problems solved by technology

However, the evapotranspiration calculated according to the crop coefficients of the four growth stages recommended by the FAO has a large deviation from the actual evapotranspiration, so scholars at home and abroad have established a variety of crop coefficient models
Although these models have achieved certain results, there are few specific calculation models that fully consider the factors affecting the crop coefficient, and most of them are calculated and fitted by traditional methods.

Method used

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  • Method for calculating summer corn actual crop coefficient based on weather and biological factors
  • Method for calculating summer corn actual crop coefficient based on weather and biological factors
  • Method for calculating summer corn actual crop coefficient based on weather and biological factors

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] Such as figure 1 As shown, the method for calculating the actual crop coefficient of summer corn based on meteorological and biological factors comprises the following steps:

[0064]Step 1: Use multiple stepwise regression to screen out the factors with a high degree of explanation among the meteorological factors affecting the crop coefficient, and select the data of biological factors in the same period;

[0065] Step 2: Use the lysimeter to measure evapotranspiration and meteorological data, and perform index fitting and Mie equation fitting on the crop coefficient, the selected meteorological factors and leaf area index respectively to establish a suitable multiplication model;

[0066] Step 3: Use the gradient descent method to solve the unknown parameters in the model to minimize the error between the calculated crop coefficient and the actual crop coefficient.

Embodiment 2

[0068] The meteorological factors mentioned in Example 1 include daily average temperature, daily maximum temperature, daily minimum temperature, sunshine hours, wind speed, absolute humidity, relative humidity, saturation difference, water vapor pressure difference and 0cm, 5cm, 10cm, 20cm, 40cm, 80cm, 160cm and 320cm ground temperature, etc., and the biological factor is leaf area index.

Embodiment 3

[0070] The specific calculation method of the actual crop coefficient is:

[0071] ET=ET 0 ·K s ·K c ;

[0072] Among them, ET is the actual evapotranspiration in mm d -1 ;

[0073] ET 0 For the reference crop evapotranspiration, the unit is mm d -1 ;

[0074] K c is the crop coefficient;

[0075] K s is the soil moisture stress coefficient.

[0076] Among them, ET 0 and K s The specific calculation method is:

[0077]

[0078] Among them, ET 0 For the reference crop evapotranspiration, the unit is mm d -1 ;

[0079] R n is the surface net radiation, the unit is MJ m -2 d -1 ;

[0080] G is the soil heat flux, the unit is MJ m -2 d -1 ;

[0081] u 2 is the wind speed at 2m above the canopy, in m / s;

[0082] e s is the saturated water vapor pressure in kPa;

[0083] e a is the actual water vapor pressure in kPa;

[0084] Δ is the slope of the curve of saturated water vapor pressure versus temperature, in kPa·℃ -1 ;

[0085] γ is the wet and dry...

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Abstract

The invention relates to a method for calculating the actual crop coefficient of summer corn based on weather and biological factors. Firstly, a large weighing lysimeter is used for actually measuringevapotranspiration data and a series of meteorological data to calculate an actual crop coefficient; fitting the crop coefficient and the leaf area index by using a Mie equation to obtain a crop coefficient influenced by the biological factor; secondly, surface temperature is screened out through multiple regression to serve as meteorological factors influencing crop coefficients; and finally, model parameters are solved through a gradient descent method, a calculation result is evaluated based on actually measured data, and the method has important significance in mastering dynamic change characteristics of crop coefficients in the summer corn growth period and accurately estimating the actual evapotranspiration of crops.

Description

technical field [0001] The invention relates to a method for calculating the actual crop coefficient of summer corn based on meteorological and biological factors, and belongs to the technical field of agricultural evaluation. Background technique [0002] Evapotranspiration is the sum of plant transpiration and soil evaporation between plants, and is an important water exchange process in the soil-plant-atmosphere system (SPAC). It has an important influence on the growth and development of crops, plays an important role in atmospheric circulation, and can further regulate the climate. Building an accurate crop coefficient model is of great significance for accurately predicting evapotranspiration and further formulating accurate irrigation plans. [0003] At present, the main method for calculating crop evapotranspiration is the crop coefficient method. The World Food and Agriculture Organization (FA0) proposed a standard method for estimating actual crop evapotranspirat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06Q50/02
CPCG06Q50/02
Inventor 王振龙范月董国强许莹莹刘猛胡军
Owner 安徽省(水利部淮河水利委员会)水利科学研究院(安徽省水利工程质量检测中心站)
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