Effect of Soil Application of Biocides on N, P, K Availability and C,N Transformations in Flooded Rice Soils

The effects of soil application of biocides (five organophosphate insecticides, two chlorinated hydrocarbon insecticides and three others containing carbamates, sulphurous esters and six weedicides) on availability of N,P,K under flooded soil conditions and their residual effects, as measured from ammonification, nitrification and CO₂ evolution have been investigated. Application of these had moderate stimulating effect on N,P,K availability during the first three months. There was some residual effect only in respect of nitrification. Therefore, there was practically no beneficial or adverse residual effect so far as rice growing was concerned.