Study on the mechanism of nitrapyrin microcapsule suspension effectively improving nitrification inhibition rate in black soil.

Nitrification inhibitors (NIs) have been widely applied to inhibit nitrification and reduce NO emissions in agriculture. However, there are still some shortcomings, e.g. short effective periods, large applying amounts, low effectiveness, easy deactivation and different effect. Thus, a nitrapyrin microcapsule suspension (CPCS) was used as a new experimental material to elaborate its effects on nitrogen transformation and microbial response mechanisms in black soil by cultivation experiments with six treatments of no fertilization (CK), urea, urea+ 0.2 % CPES, urea+ 0.1 % CPCS, urea+ 0.2 % CPCS, and urea+ 0.3 % CPCS. The content of ammonium, nitrate nitrogen, functional microbial activity, degradation rate and adsorption characteristics of CPCS in the soil at different incubating times were determine. Compared with the nitrapyrin emulsifiable concentrate (CPEC) treatment, the degradation rate of CPCS decreased by 21.54 %, the half-life increased by 10.2 days, and the adsorption rate of nitrapyrin on black soil decreased more than 6-fold. CPCS effectively inhibited the transformation of ammonium nitrogen to nitrate nitrogen within more than 42 days. CPCS had a negative effect on amoA gene abundance and a positive effect on nrfA gene abundance. The research results provide a basic theoretical support for the application of CPCS on black soil.