Reducing environmental risks of chlorpyrifos application in typical soils by adding appropriate exogenous organic matter: Evidence from a simulated paddy field experiment

Abstract

Chlorpyrifos (CPF), as an organophosphate insecticide extensively used in the modern agricultural system, has been gradually banned in many countries due to its reported health risks to organisms, including humans. This study used simulated paddy field experiments and carbon-14 tracing to explore the possibility of reducing environmental risks of chlorpyrifos application through appropriate agronomic practice. Results showed 14C-CPF concentration in rice plants planted in the red soil (RS) was significantly higher than that in black soil (BS) and fluvo-aquic soil (FS). The application of biochar and chicken manure in RS reduced 14C-CPF accumulation in rice plants, and the content of 14C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of 14C-CPF, especially in FS with the highest risk of 14C-CPF migration. The addition of chicken manure in FS reduced the migration of 14C-CPF and the total residual amount of 14C-CPF in the soil. In addition, chicken manure treatment increased the formation of 14C-bound residues (BRs) in soils and changed the distribution 14C-BRs in humus. The results indicated that the degree of environmental risks associated with the CPF application varies with soil types and could be reduced by introducing suitable exogenous organic matter into different soils, which is of great significance for guiding the scientific application of chlorpyrifos in agronomic practices.