Nitrous oxide emissions from maize-wheat field during four successive years in the North China Plain

Le résumé fourni par la source

Abstract. Agricultural soil with fertilization is a main anthropogenic source for atmospheric N2O. N2O fluxes from a maize-wheat field in the North China Plain (NCP) were investigated for four successive years using static chamber method. The annual N2O fluxes from control (without fertilization) and fertilization plots were 1.5 ± 0.2 and 9.4 ± 1.7 kg N ha−1 yr−1 in 2008–2009, 2.0 ± 0.01 and 4.0 ± 0.03 kg N ha−1 yr−1 in 2009–2010, 1.3 ± 0.02 and 5.0 ± 0.3kg N ha−1 yr−1 in 2010–2011, and 2.7 ± 0.6 and 12.5 ± 0.1 kg N ha−1 yr−1 in 2011–2012, respectively. Fertilizer-induced emission factors (EFs) in the corresponding years were 2.4, 0.60, 1.1 and 2.9%, respectively. Significant linear correlation between fertilized-induced N2O emission (Y, kg N ha−1 yr−1) and rainfall 4 day before and 10 days after fertilization (X, mm) was found as Y = 0.04767X − 1.06453 (N = 4, R2 = 0.99241, P = 0.00253). Therefore, the remarkable interannual variations of N2O emissions and the EFs from the agricultural field were mainly ascribed to the rainfall. The total N2O emission from the agricultural field in the NCP was estimated to be 144 Gg N yr−1 based on the average flux derived from the measurements of four years, and the fertilizer-induced N2O emission accounted for about 76% (110 Gg N yr−1) of total emission.

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