Effects of Nitrogen Application on N2O Flux from Fluvo-Aquic Soil Subject to Freezing-Thawing Process

• Published in: Agricultural sciences in China Vol. 9; no. 4; pp. 577 - 582
• Main Authors: WANG, Feng, GAO, Shang-bin, ZHANG, Ke-qiang, LI, Hai-bo, BAI, Li-jing, HUANG, Zhi-ping, MI, Chang-hong
• Format: Journal Article
• Language: English
• Published: 01.04.2010
• Subjects: N2O排放通量; 解冻过程; NH4+-N; freezing-thawing process; N2O flux; amide-N; NO3 > N
• ISSN: 1671-2927
• DOI: 10.1016/S1671-2927(09)60131-0

A lab-incubation experiment was conducted to investigate the effects of different forms of nitrogen application （ammonium, NH4＋-N; nitrate, NO3--N; and amide-N, NH2-N） and different concentrations （40, 200 and 800 mg L-1） on N2O emission from the fluvo-aquic soil subjected to a freezing-thawing cycling. N2O emission sharply decreased at the start of soil freezing, and then showed a smooth line with soil freezing. In subject to soil thawing, N2O emission increased and reached a peak at the initial thawing stage. The average N2O emissions with addition of NH4＋-N, NO3 -N and NH2-N are 119.01, 611.61 and 148. 22 ug m-2 h-1, respectively, at the concentration of 40 mg L-1; 205.28, 1 084.40 and 106.13 ug m2 h-1 at the concentration of 200 mg L-1; and 693.95, 1 820.02 and 49.74 ug m-2 h4 at the concentration of 800 mg L-1. The control is only 100.35 ug m-2 h-1. N2O emissions with addition of NH4＋-N and NO3--N increased with increasing concentration, by ranging from 17.49 to 425.67% for NH4＋-N, and from 563.38 to 1458.6% for NO3--N compared with control. There was a timelag for N2O emission to reach a steady state with an increase of concentration. In contrast, by adding NH2-N to soil, N2O emission decreased with increasing concentration. In sum, NH4＋-N or NO3--N fertilizer incorporated in soil enhanced the cumulative N2O emission from the fluvo-aquic soil relative to amide-N. This study suggested that ammonium and nitrate concentration in overwintering water should be less than 200 and 40 mg L-1 in order to reduce N2O emissions from soil, regardless of amide-N.