| "The people record food as the heaven,food and safety as the first",it is recorded in the book 'Han shu li shi qi zhuan'.It can be seen that our country 's people have a very early sense of food safety.In recent years,the rapid development of agricultural technology has basically solved the issue of human food and clothing.However,due to the heavy use of pesticides,the problem of pesticide residue has become increasingly prominent,it has increasingly become one of the hot topics that people have discussed and focused on.It has also developed into a worldwide problem and has gradually become an important indicator of a country's economic strength.Heilongjiang Province,as the largest province of rice cultivation in China,has a strategic position of "China's Big Grainary".With the increase of rice-growing area and the extension of planning time,the occurrence of pests and weeds in paddy fields has become increasingly complex,causing serious losses of rice yield and quality.However,humans have so far not found a cultivation method that can protect crops without causing harm to food safety and the environment,therefore pesticide will continue to play an irreplaceable role in agricultural production for long time,the problem of pesticide residue will remain inevitable in our lives.In this paper,we use the known geographical coordinates of pests and weeds in the rice-growing area and combine with the environment factors,use the MaxEnt model and ArcGIS technology to estimate the spatial distribution risk of pests and weeds in the rice-growing area in Heilongjiang Province,and establish of pesticide residue assessment method in paddy field,presenting different degrees of risk area.In addition,under the different RCP scenario simulation,the trend of risk migration of pesticide residues in paddy field of Heilongjiang Province was studied to understand the future direction of risk transfer,which facilitates early management in high-risk areas and provides effective guidance for rice cultivation.This article specifically studies from the following aspects:(1)Screening the environment variables of pesticide residue distribution in the rice-growing area in Heilongjiang Province;(2)Predicting the spatial distribution of rice and pests and weeds in Heilongjiang Province;(3)Establish of pesticide residue assessment method in paddy field;(4)To estimate the distribution of pesticide residue in each accumulated temperate zone in Heilongjiang Province;(5)Under different RCP scenario simulation the risk migration trends of rice pesticide residue in paddy field in Heilongjiang Province.Get the following conclusion:(1)Through screening environment variables affecting the distribution of rice in various temperature zones in Heilongjiang Province and environment variables affecting the distribution of pests and weeds in rice growing areas,the main environment variables affecting the distribution of rice and weeds and pests were obtained.(2)The distribution of pesticide residue in each accumulated temperature zone of Heilongjiang Province presents different degrees of risk patterns that can occur.It can accurately understand the natural environment and distribution characteristics of pests and weeds that damage crops,and can accurately grasp the occurrence of pests and weeds.The central area provides effective guidance for the rational use of pesticide.(3)The risk distribution of pesticide residue in cold regions of Heilongjiang Province under different scenarios was mainly divided into two parts.The first part was mainly concentrated in the rice growing areas of the second accumulated temperature zone,the future gravity center under the four scenario simulations moved to the south compared to the contemporary gravity center.The second part is also mainly concentrated in second accumulated simulations moves towards the southeast as compared to the contemporary center of gravity,providing effective guidance for future rice cultivation areas and preventing large-scale diseases. |
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