Method for forecasting application amount of rice nitrogen fertilizer

Abstract

The invention relates to a method for forecasting application amount of a rice nitrogen fertilizer. The method comprises the following steps of: firstly determining a nitrogen returning index and a target yield of a specific field parcel and the nitrogen absorption amount of 100 kilograms of grains, and then forecasting the application amount of the rice nitrogen fertilizer with the following formula: the application amount of the rice nitrogen fertilizer is obtained by multiplying the nitrogen returning index, the target yield and the nitrogen absorption amount of 100 kilograms of grains, and then dividing by100, wherein the nitrogen returning index is obtained by subtracting (l-the nitrogen net loss rate) from l; l represents the fertilizer nitrogen fed into the soil during the production of early rice in the field parcel; the nitrogen net loss rate is percentage of the sum of the increase amount of nitrogen output from the soil to the environment after the nitrogen fertilizer is fed and the increase amount of nitrogen in the soil to the feeding amount of the nitrogen fertilizer; the l-the nitrogen net loss rate represents the actual nitrogen content in the harvested rice; the target yield is obtained by multiplying (l+the progressive increase rate) and the average unit yield in the previous three years, and the unit of the target yield is kg/Mu; and the nitrogen absorption amount of 100 kilograms of grains is the nitrogen required to be absorbed at every economical yield of 100 kilograms, and the unit is kgN/kg.

Description

technical field [0001] The invention relates to a method for predicting the application amount of rice nitrogen fertilizer. Background technique [0002] Rice growth requires nitrogen fertilizer. The methods for recommending rice nitrogen fertilizer application can be divided into two categories, that is, the recommendation method based on soil and plant tests and the recommendation method based on fertilizer effect function. The former method is in the It is rarely used in production, and the latter method (hereinafter referred to as the fertilizer effect function method) is recommended and currently commonly used in my country's "Technical Specifications for Soil Testing and Formulated Fertilization". The implementation of the fertilizer effect function method first needs to conduct fertilizer field experiments, obtain the fertilizer effect equation according to the test results, and then derive the equation, which is recommended by the marginal yield (dy / dx=0) and marginal...

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Problems solved by technology

The basic principle is a simple soil nitrogen balance, that is: the amount of nitrogen applied to crops in the current season = nitrogen demand for target yield - soil nitrogen supply. The calculation of soil nitrogen balance does not consider the loss of nitrogen, and the specific field is accurate. The nitrogen supply capacity of the soil is not easy to obtain, so it is difficult to predict the amount of nitrogen application in a specific field in advance

The "Technical Specifications for Soil Testing Formula Fertilization" promulgated by the Ministry of Agriculture in 2005 and revised in 2011 also introduced a method to calculate the amount of fertilizer using nutrient balance. The calculation formula is: amount of fertilizer = (nutrients required for target yield Total amount - soil fertilizer supply) ÷ (nutrient content in fertilizer × fertilizer utilization rate in the current season), although the loss of fertilizer (fertilizer utilization rate in the current season) is considered, but because the soil fertilizer supply capacity is also not easy to obtain, and there is no It is possible to predict the utilization rate of fertilizers in the current season in advance, and this method is rarely used in actual production

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