Abstract
A field experiment was conducted study the effect of biochar and a nitrification inhibitor (nitrapyrin) on NH3 and N2O emissions from a silt clay loam soil near Peshawar, Pakistan. The experimental design was a randomized complete block with eight treatments in three replicates: (no urea), urea (150 kg N ha(-1)), B (6 t ha(-1)), B (12 t ha(-1)), urea + B6, urea + B12, urea + B6 + NI (700 g ha(-1)), and urea + B12 + NI. Application of urea with two levels of biochar reduced total NH3 by 18-29% and N2O emissions by 25-22%, respectively, relative to the treatment with urea alone. Nitrous oxide emission was significantly lower (51%) in the nitrapyrin treatment than in the urea-alone treatment (P < 0.05), but there was no effect on NH3 emission. The wheat plant biomass, grain yield, and total N uptake increased significantly by 10-21%, 05-15%, and by 11-25%, respectively, in the treatments with urea and biochar, relative to the treatment with urea alone. Additionally, nitrapyrin further enhanced biomass, grain yield, and total N uptake by 33%, 19%, and 46%, respectively, relative to the treatment with urea alone. The results indicate that application of urea with biochar or in combination with nitrapyrin has the potential to mitigate NH3 and N2O emissions, which are important to increase nitrogen use efficiency and wheat productivity.