Residual Distribution And Degradation Dynamics Of Azoxystrobin On Soybean

Soybean is one of the indispensable commercial crops in our daily life.The control of pests and diseases is generally dependent on the use of chemical pesticides.As a broad-spectrum and high-efficiency fungicide,azoxystrobin is widely used in the prevention and treatment of soybean diseases.In order to clarify the safety of azoxystrobin in soybean,this paper studied the original accumulation,residual distribution and degradation dynamics of azoxystrobin in different parts of soybean plants after application in Anhui,Jilin and Shandong,and proposed according to the terminal residues.Reasonable application recommendations for 250g/L azoxystrobin suspension.The main results are as follows:1.An Ultra Performance Liquid Chromatography analysis method for the determination of azoxystrobin residues in soybean was established.When the concentration was 0.002,0.02,0.2mg/kg,the average recovery of azoxystrobin in soybean plants was 79.2%?86.3%,the relative standard deviation was 2.9%?9.1%;the added concentration was 0.01,0.02,0.2.At mg/kg,the average recovery of azoxystrobin in soybean was 104.3%?111.1%,and the relative standard deviation was 1.6%-4.7%.When the concentration was 0.01,0.02,lmg/kg,the average recovery of azoxystrobin in soil was 88.0%?107.2%,the relative standard deviation was 0.9%?2.8%,and the added concentration was 0.005,0.05,0.5mg/At the time of kg,the average recovery of azoxystrobin in the root system was 82.5%-87.5%,and the relative standard deviation was 1.1%?12.8%.2.The Original accumulation and residual distribution of soybean in different matrices were studied after applying 250 g/L azoxystrobin suspension in soybean field under natural conditions in Anhui,Jilin and Shandong.According to the sample test,the Original accumulations of soybean upper leaves,lower leaves,upper stems,lower stems and pods were 10.61-21.73 mg/kg,5.58-14.71 mg/kg,0.52-3.48 mg/kg,0.42-0.83 mg/kg and 0.11-1.3 mg/kg.It is concluded that the active constituents are mainly deposited in the upper and lower leaves of soybean;the original accumulation residue of the upper leaves accounts for more than 50%;the original accumulation of azoxystrobin in the upper and upper stems is higher than that of the lower leaves.Leaves and lower stems;the amount of primitive deposits on the pods is relatively low.Azoxystrobin remained in the leaves mainly after 21 days of application in soybean fields;the residual amount of azoxystrobin in the upper leaves of Jilin test site remained relatively high in 7 days;the residues in the upper and lower leaves of Anhui and Shandong test sites remained.The amount is basically the same in the application.3.The degradation dynamics of azoxystrobin in soybeans in Anhui,Jilin and Shandong were studied.The results showed that the degradation dynamics of azoxystrobin in the upper lea-ves,lower leaves,upper stems,lower stems and pods of soybeans were consistent with the first-order dynamics of chemical reactions.The equations have a digestion half-life of 2.38-5.59 d,3.87-6.73 d,3.89-12.2 d,6.19-9.49 d and 3.37-8.35 d,respectively.4.The terminal residues of azoxystrobin in soybeans in Anhui,Jilin and Shandong was studied.The test results showed that the doses were 75 ga.i/hm2,112.5 ga.i/hm2,150 ga.i/hm2,225 ga.i/hm2,respectively.Soybean leaves,pods,shelled kernels and soil were collected before and 2 hours after application.The terminal residues of azoxystrobin in soybean seeds was between 0.004?0.978mg/kg after 14 days of last application.this paper proposes that the reasonable application of 250g/L azoxystrobin suspension in soybeans is as follows:the dosage is not more than 75 ga.i/hm2,the application frequency is not more than 3 times,and the sampling interval is Not less than 2h.