Effect of nitrification inhibitors on mitigating N2O and NO emissions from an agricultural field under drip fertigation in the North China Plain.

N2O and NO emissions from a winter wheat-summer maize rotation field with five different treatments in the North China Plain (NCP) were comparably investigated from 8 October 2014 to 11 October 2015. Compared with the treatments with only flood or drip irrigation, evident emission peaks of N2O and NO from the fertilization treatments with flood irrigation (A-Flood) and with drip fertigation (A-Drip) were observed after each fertilization event, whereas their emissions from the fertilization treatments with nitrification inhibitors under drip fertigation (A+DCD-Drip and A+Nitrapyrin-Drip) were greatly suppressed. The reduction effect of the nitrification inhibitors on N2O and NO emissions was found to be more conspicuous during the maize season than during the wheat season, implying that the soil temperature could play an important role in the reduction effect. Compared with the A-Flood treatment, the annual cumulative emission from the A-Drip treatment reduced by 22% for N2O and increased by 18% for NO, whereas the reductions of N2O and NO from the treatments with nitrification inhibitors could achieve as high as 66% and 95%, respectively. The yields of the maize were significantly greater from the A-Drip and A+Nitrapyrin-Drip treatments than from the A-Flood treatment, and the yields of the wheat were almost same among the treatments of A-Flood, A-Drip and A+DCD-Drip. Considering the yields, the water saving and the reduction of N2O and NO emissions, the application of nitrification inhibitor combined with drip fertigation is recommended in the NCP.