Impact of urease and nitrification inhibitors on nitrous oxide emissions from fluvo-aquic soil in the North China Plain.

Little information is available on the effects of urease inhibitor, N-( n-butyl)thiophosphoric triamide (NBPT), and nitrification inhibitor, dicyandiamide (DCD), on nitrous oxide (NO) emissions from fluvo-aquic soil in the North China Plain. A field experiment was conducted at the Fengqiu State Key Agro-Ecological Experimental Station, Henan Province, China, to study the influence of urea added with NBPT, DCD, and combination of both NBPT and DCD on NO emissions during the maize growing season in 2009. Two peaks of NO fluxes occurred during the maize growing season: the small one following irrigation and the big one after nitrogen (N) fertilizer application. There was a significant positive relationship between ln [NO flux] and soil moisture during the maize growing season excluding the 11-day datasets after N fertilizer application, indicating that NO flux was affected by soil moisture. Mean NO flux was the highest in the control with urea alone, while the application of urea together with NBPT, DCD, and NBPT + DCD significantly lowered the mean NO flux. Total NO emission in the NBPT + DCD, DCD, NBPT, and urea alone treatments during the experimental period was 0.41, 0.47, 0.48, and 0.77 kg NO-N ha, respectively. Application of urea with NBPT, DCD, and NBPT + DCD reduced NO emission by 37.7%, 39.0%, and 46.8%, respectively, over urea alone. Based on our findings, the combination of DCD and NBPT together with urea may reduce NO emission and improve the maize yield from fluvo-aquic soil in the North China Plain. [ABSTRACT FROM AUTHOR]