N_2O emissions from a cultivated Andisol after application of nitrogen fertilizers with or without nitrification inhibitor under soil moisture regime

Article type: Research Article

Authors: FAN, Xiao-hui | Tsuruta, Haruo

Affiliations: Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | National Institute of Agro-Environmental Sciences, Kannondai 3-1-1, Tsukuba 305, Japan

Note: [] Corresponding author. E-mail: [email protected]

Abstract: The aim of this work was to examine the emission of N_2O from soils following addition of nitrogen fertilizer with a nitrification inhibitor (+inh) or without the nitrification inhibitor (−inh) at different soil water regime. Higher soil moisture contents increased the total N_2O emissions in all treatments with total emissions being 7 times larger for the CK and >20 times larger for the fertilizer treatments at 85% WFPS (soil water filled pore space) than at 40% WFPS. The rates of N_2O emissions at 40% WFPS under all treatments were small. The maximum emission rate at 55% WFPS without the nitrification inhibitor (−inh) occurred later (day 11) than those of 70% WFPS (−inh) samples (day 8). The inhibition period was 4–22 d for 55% WFPS and 1–15 d for 70% WFPS comparing the rates of N_2O emissions treated (+inh) with (−inh). The maximum emission rates at 85% WFPS were higher than those at the other levels of soil water content for all treatments. The samples (+inh) released less N_2O than (−inh) samples at the early stage. Nevertheless, N_2O emissions from (+inh) samples lasted longer than in the (−inh) treatment. Changes in mineral N at 55%, 70% and 85% WFPS followed the same pattern. NH_4^+-N concentrations decreased while NO_3^--N concentrations increased from the beginning of incubation. NH^+_4-N concentrations from 40% WFPS treatment declined more slowly than those of the other three levels of soil water content. Nitrification was faster in the (−inh) samples with 100% NH_4^+-N nitrified after 22 d (50% WFPS) and 15 d (70% and 85% WFPS). N_2O emissions increased with soil water content. Adding N-fertilizer increased emissions of N_2O. The application of the nitrification inhibitor significantly reduced total N_2O emissions from 30.5% (at 85%WFPS) to 43.6% (at 55% WFPS).

Keywords: N[TeX:] _2O emission, nitrification inhibitor, soil water content, upland soil samples

Journal: Journal of Environmental Sciences, vol. 16, no. 5, pp. 735-737, 2004