Cypermethrin on Soil Enzymatic Activity and Its Degradation in Different Fertilization Soils

Using long-term experiment soil(classified as aquic inceptisol),degradation of cypermethrin in different fertilization soils and effect of cypermethrin on different fertilization soil enzymatic activity were conducted.Study results showed dissipation of pesticide was significantly influenced by fertilization.After long-term application of N fertilizer,soil available N content increased and degradation was inhibited.However application of P fertilizer could facilitate this process.Addition of organic manure into soil,soil organic matter content increased and so did degradation rate,but dissipation time of cypermethrin and lag phase prolonged.Degradation of cypermethrin in soils followed the first-order kinetic equation,and DT50 was from 10.13 days(PK) to 14.58 days(NK).Dehydrogenase and urease activities increased significantly after addition of cypermethrin into soils,and increments of different fertilization treatment varied.Changes of phosphatase activity differed in different treatment soils.Soil enzymatic activity could recover at day 26 of incubation in almost treatment soils.It is of great importance for sustainable agriculture to study the interaction among pesticide residues,fertilization and enzymatic activity in soil.