Deepened snow cover alters biotic and abiotic controls on nitrogen loss during non-growing season in temperate grassland
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ORIGINAL PAPER
Deepened snow cover alters biotic and abiotic controls on nitrogen loss during non-growing season in temperate grasslands Zhou Jia 1,2 & Ping Li 1,2 & Yuntao Wu 1,2 & Sen Yang 1,2 & Chengzhang Wang 1,2 & Bin Wang 1,2 & Lu Yang 1,2 & Xin Wang 1 & Jing Li 1,2 & Ziyang Peng 1,2 & Lulu Guo 1,2 & Weixing Liu 1 & Lingli Liu 1,2 Received: 16 June 2020 / Revised: 20 September 2020 / Accepted: 27 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Despite the fact that winter lasts for a third of the year in the temperate grasslands, winter processes in these ecosystems have been inadequately represented in global climate change studies. While climate change increases the snow depth in the Mongolian Plateau, grasslands in this region are also simultaneously facing high pressure from land use changes, such as grazing, mowing, and agricultural cultivation. To elucidate how these changes affect the grasslands’ winter nitrogen (N) budget, we manipulated snow depth under different land use practices and conducted a 15NH415NO3-labeling experiment. The change in 15N recovery during winter time was assessed by measuring the 15N/14N ratio of root, litter, and soils (0–5 cm and 5–20 cm). Soil microbial biomass carbon and N as well as N2O emission were also measured. Compared with ambient snow, the deepened snow treatment reduced total 15N recovery on average by 21.7% and 19.2% during the first and second winter, respectively. The decrease in 15N recovery was primarily attributed to deepened snow increasing the soil temperature and thus microbial biomass. The higher microbial activity under deepened snow then subsequently resulted in higher gaseous N loss. The N2O emission under deepened snow (0.144 kg N ha−1) was 6.26 times than that of under ambient snow (0.023 kg N ha−1) during the period of snow cover and spring thaw. Although deepened snow reduced soil 15N recovery, the surface soil N concentration remained unchanged after five years’ deepened snow treatment because deepened snow reduced soil N loss via wind erosion by 86%. Keywords Snow cover . N budget . 15N labeling . N2O emission . Soil erosion . Land use changes
Introduction To date, most of the studies on the nitrogen (N) cycle have primarily focused on N dynamics during the growing season. However, a cumulative body of evidence has demonstrated that soil N dynamics during the non-growing season can greatly influence the annual N budget (Campbell et al. 2005; Duran et al. 2014; Joseph and Henry 2008; Wolf et al. 2010). For instance, a study in Inner Mongolia found that nitrous Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00374-020-01514-4) contains supplementary material, which is available to authorized users. * Lingli Liu [email protected] 1
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
2
University of Chinese Academy of Sciences, Beijing 100049, China
oxide (N2O) pulses emitted
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