Effects Of Agricultural Antibiotics On Nitrogen Mineralization In Black Soil

With the development of agriculture and the demand for the quality and safety of agricultural products,biopesticides are gradually widely used.In the practical application of biopesticides,the phenomenon of excessive application in pursuit of efficacy often occurs,which intensifies its accumulation in the environment and the risk to the ecosystem;At present,the environmental effect evaluation of pesticides mainly focuses on chemical synthetic pesticides,and the reports on biological pesticides are rare.In this paper,taking black soil as the test soil,taking abamectin(insecticide),kasugamycin(bactericide)and validamycin(fungicide)as the research object,the content of ammonium nitrogen and nitrate nitrogen in soil were measured under indoor culture conditions,To study the effects of three pesticides on the nitrogen supply capacity of black soil under different application periods and dosage(recommended concentration,recorded as low concentration;10 times recommended concentration,recorded as medium concentration;100 times recommended concentration,recorded as high concentration),and to reveal the mechanism of biological pesticides affecting nitrogen mineralization by measuring the activities of soil urease,protease and arylamidase,so as to provide a scientific basis for correctly evaluating the environmental effects of biological pesticides.The main conclusions are as follows:(1)Abamectin has different effects on the activities of soil urease,protease and arylamidase,and has a positive effect on soil urease activity.Compared with the control group,urease activity increased by 41.99%.Abamectin showed negative effects on soil protease and arylamidase activities.Compared with the control,the activities of the above two enzymes decreased by 69.25% and 40.98%.When the concentration of kasugamycin and validamycin exceeded the recommended concentration,they inhibited the activities of soil urease,protease and arylamidase.The maximum inhibition rates of high concentration kasugamycin on the activities of these three enzymes were 16.48%,44.67% and 34.32%,respectively;The maximum inhibitory rates of high concentration Validamycin on the activities of these three enzymes were17.32%,61.65% and 28.04%,respectively.(2)Abamectin promoted the content of soil ammonium nitrogen,and the stimulation degree was directly proportional to the application concentration.Compared with the control group,the content of soil ammonium nitrogen increased by 71.97%.Abamectin inhibited the contents of soil nitrate nitrogen and net mineralized nitrogen.Compared with the control,the contents of soil ammonium nitrogen and net mineralized nitrogen decreased by 31.04% and 44.36%.Kasugamycin and alidamycin had similar effects on soil ammonium nitrogen and nitrate nitrogen.When exceeding the recommended concentration,they both inhibited the content of soil ammonium nitrogen and promoted the content of nitrate nitrogen.Compared with the control group,the content of soil ammonium nitrogen in high concentration kasugamycin and Validamycin decreased by31.17% and 50.75% respectively.(3)The grey correlation analysis shows that the mineralization of black soil is inhibited by the three pesticides,and the degree of negative effect is as follows:abamectin > kasugamycin > validamycin,and the negative effect increases when it exceeds the recommended concentration.