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

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 C-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 C-CPF accumulation in rice plants, and the content of C-CPF in rice grains decreased by 25% and 50%, respectively. Adding biochar to all three soils reduced the migration of C-CPF, especially in FS with the highest risk of C-CPF migration. The addition of chicken manure in FS reduced the migration of C-CPF and the total residual amount of C-CPF in the soil. In addition, chicken manure treatment increased the formation of C-bound residues (BRs) in soils and changed the distribution C-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.