Inhibition of methane emissions from Chinese rice fields by nitrogen deposition based on the DNDC model. (September 2020)

• Record Type: Journal Article
• Authors: Wang, Zhen; Zhang, Xiuying; Liu, Lei; Wang, Shanqian; Zhao, Limin; Wu, Xiaodi; Zhang, Wuting; Huang, Xianjin
• Is Part Of: Agricultural systems. Volume 184(2020)
• Publication Date: 2020-09
• Subjects: Nitrogen deposition -- Methane emissions -- DNDC -- Rice paddies -- China -- Inhibitory effect; Agricultural systems -- Periodicals; Agriculture -- Environmental aspects -- Periodicals; 338.16
• DOI: 10.1016/j.agsy.2020.102919
• Languages: English
• ISSNs: 0308-521X

Abstract

Abstract: Nitrogen (N) deposition has rapidly increased in China, and its impact on ecosystems has received extensive attention. In the present study, the net effect of increased N deposition on methane (CH4 ) emissions from rice fields across China was evaluated using the validated DNDC (DeNitrification-DeComposition) model. The results showed that N deposition produces a slight increase in rice biomass and weakly inhibits CH4 emissions, under the current N fertilizer application practices (excessive N fertilizer) in paddy fields. Nationally, N deposition reduces total CH4 emissions by 0.04 Tg yr −1 . CH4 emissions are reduced by 1.38 and 1.69 kg CH4 ha −1 yr −1 (accounting for 0.6% and 0.2% of the average CH4 emissions) in a mid-season drainage water regime for single- and double-cropping rice, respectively. N deposition showed significantly influence on CH4 emission reduction ( R = 0.86 and 0.74 for single- and double-cropping rice, respectively, p < 0.01). The largest reduction in the CH4 flux of single-cropping rice was mainly concentrated in AEZ (agroecological zone) 6A and AEZ 7, while the largest reduction for double-cropping rice was mainly distributed in the Poyang Lake Basin and Dongting Lake Basin. It should be noticed that the net response of CH4 emissions to N deposition (−0.07 and − 0.14 kg CH4 ha −1 kg −1 N for single- and double-cropping rice, respectively) was greater than that to N fertilizers (−0.05 kg CH4 ha −1 kg −1 N) under the same water management practices, which mainly because the nitrate nitrogen in N deposition increases the soil redox potential, thus inhibiting the production of CH4 . These results provide a new understanding of the ecological effect of N deposition on agricultural ecosystems. Highlights: The N deposition inhibits total CH4 emissions by 0.04 Tg yr −1 . There was a significant correlation between N deposition and reduced CH4 emissions. The CH4 flux was reduced by 0.07 kg per kg of N deposition in single-cropping rice. The CH4 flux was reduced by 0.14 kg per kg of N deposition in double-cropping rice.