Open AccessGrazing offsets the stimulating effects of nitrogen addition on soil CH4 emissions in a meadow steppe in Northeast China
Author(s) -
Rongrong Ren,
Wanling Xu,
Mingming Zhao,
Wei Sun
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0225862
Subject(s) - grazing , steppe , environmental science , flux (metallurgy) , nitrogen , deposition (geology) , agronomy , zoology , hydrology (agriculture) , soil science , ecology , chemistry , biology , geology , organic chemistry , paleontology , geotechnical engineering , sediment
Grazing is the most common land use type for grasslands, and grazing may alter the impacts of the predicted enhancement of nitrogen deposition on soil CH 4 flux. To understand the effects of nitrogen addition, grazing, and their interactions on soil CH 4 flux, we conducted a field study on CH 4 flux in a meadow steppe in Northeast China from 2017 to 2018. We measured the soil CH 4 flux and soil physiochemical and vegetation parameters. The studied meadow steppe soil acted as a CH 4 source due to the legacy effects of an extreme rainfall event. During the experimental period, the average CH 4 fluxes were 7.8 ± 1.0, 5.8 ± 0.5, 9.3 ± 0.9 and 7.6 ± 0.6 μg m -2 h -1 for the CK (control), G (grazing), N (nitrogen addition) and NG (grazing and nitrogen addition) treatments, respectively. The cumulative CH 4 fluxes were 24.9 ± 2.6, 11.5 ± 4.9, 28.8 ± 4.2 and 17.8 ± 3.5 μg m -2 yr -1 for the CK, G, N and NG treatments, respectively. The N addition increased the average CH 4 flux by 19%, and the grazing treatment reduced it by 25%. The soil CH 4 flux was positively correlated with the 0–10 cm soil water filled pore space ( P < 0.01), soil NH 4 + -N ( P < 0.01) and soil NO 3 - -N ( P < 0.01), but negatively correlated with the 0–10 cm soil temperature ( P < 0.01), except for the sampling dates that were strongly influenced by the extreme rainfall event. The average CH 4 flux was significantly ( P < 0.05) affected by the grazing and N addition treatments with the N addition treatment significantly ( P < 0.05) increased the CH 4 flux, whereas grazing significantly ( P < 0.05) decreased the CH 4 flux. Grazing offset the stimulating effects of N addition on CH 4 flux, and there was no difference ( P = 0.79) in the CH 4 flux between the CK and NG plots. In summary, moderate grazing has the potential to reduce the negative impacts of N addition on CH 4 flux and can increase the capacity of the soil CH 4 sink in the studied meadow steppe.