Response surface optimization method for reducing heavy metal content of crops in biogas slurry returning mode

Abstract

The invention relates to a response surface optimization method for reducing the heavy metal content of crops in a biogas slurry returning mode, which comprises the following steps: selecting a plurality of test factors, and setting the gradient value of each test factor in each test based on the Box-Behnken principle of a response surface method; based on the set gradient value, carrying out potting tests on a plurality of biogas slurry returning crops, and collecting the heavy metal element content of the plants after the growth period of the crops ends; performing polynomial fitting based on test data by taking the heavy metal element content as a dependent variable and the gradient of each test factor as an independent variable to obtain a multiple regression model equation; and obtaining a response surface diagram based on the multiple regression model equation, and obtaining an optimal condition for minimizing the heavy metal content of the crops cultured in the biogas slurry. Compared with the prior art, the method has the advantages of flexibility, rapidness, convenience, low cost and the like, and an optimal solution can be provided for the problem of heavy metal accumulation of crops returning the biogas slurry to the field.

Description

technical field [0001] The invention belongs to the technical field of heavy metal pollution control, and relates to a crop growth optimization control method, in particular to a response surface optimization method for reducing the heavy metal content of crops under the mode of biogas slurry returning to the field. Background technique [0002] Biogas slurry is the wastewater produced after the biogas project is used to treat agricultural and animal husbandry waste such as livestock manure. It is rich in a large amount of nitrogen, phosphorus, potassium and other plant essential macronutrient elements and plant essential micronutrient elements such as iron, zinc, and copper. The use of biogas slurry in crop production is beneficial to maximize the utilization of biogas slurry, reduce the use of chemical fertilizers and pesticides, improve soil, and increase crop yield and quality. However, unreasonable biogas slurry application methods will also lead to excessive deposition ...

AI Technical Summary

Problems solved by technology

[0002] Biogas slurry is the wastewater produced after the biogas project is used to treat agricultural and animal husbandry waste such as livestock manure. It is rich in a large amount of nitrogen, phosphorus, potassium and other plant essential macronutrient elements and plant essential micronutrient elements such as iron, zinc, and copper. The use of biogas slurry in crop production is beneficial to maximize the utilization of biogas slurry, reduce the use of chemical fertilizers and pesticides, improve soil, and increase crop yield and quality. However, unreasonable biogas slurry application methods will also lead to excessive deposition of heavy metals, threatening crops Yield and food security

[0003] At present, the control of heavy metal pollution is mainly divided into biological control methods and physical adsorption methods. The biological control methods are low in cost and environmentally friendly, but slow in effect. The composite bioremediation heavy metal method of earthworms and microbial agents; the physical adsorption method has quick results, but the cost is high and it is easy to cause secondary pollution. For example, Chinese patent application CN112960725A discloses a method for utilizing nanoparticles to physically adsorb heavy metal impurities in biogas slurry

The organic combination of the two methods can form a synergistic effect to enhance the removal effect of heavy metals. Chinese patent application CN113058984A discloses a cadmium and lead restoration method for introducing herbaceous fiber crops after adding coconut shell biochar passivation agent to farmland soil, but the method is fixed. The weights of the two methods are not specified, and it does not have the operability in different application environments

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