文献类型：期刊文献

英文题名：Effects of nitrogen and water addition on N2O emissions in temperate grasslands, northern China

作者：Guo, Yu[1,2] Dong, Yunshe[1] Peng, Qin[1] Li, ZhaoLin[1,2] He, YunLong[3] Yan, ZhongQing[4] Qin, Shuqi[1,2]

第一作者：Guo, Yu

通信作者：Peng, Q[1]

机构：[1]Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Land Surface Pattern & Simulat, 11A,Datun Rd, Beijing 100101, Peoples R China;[2]Univ Chinese Acad Sci, Beijing 100049, Peoples R China;[3]Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Ecosyst Network Observat & Modeling, Beijing 100101, Peoples R China;[4]Chinese Acad Forestry, Inst Wetland Res, Beijing 100091, Peoples R China

年份：2022

卷号：177

外文期刊名：APPLIED SOIL ECOLOGY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000812321300014)】；

基金：This study was supported by the National Natural Science Foundation of China (42177224, 41673086, 41330528, and 41573131) . We are grateful to the Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences for their assistance with accommodation.

语种：英文

外文关键词：N2O emissions; Global change; Fertilization; Water addition; Temperate grassland

摘要：Temperate grasslands are considered an important natural source of the trace greenhouse gas N2O, which has attracted much attention in recent years. Increased annual precipitation and N deposition have been observed in temperate grasslands in northern China owing to climate change and anthropogenic activities. Although the individual effects of increased precipitation and N deposition on N2O emissions have been extensively reported, their interactive effects remain unclear. An in situ experiment with two levels of water supply (ambient and +15% precipitation levels) and four levels of N application (0, 25, 50, and 100 kg N ha(-1) yr(-1)) was conducted in a semi-arid temperate grassland from 2016 to 2018 to quantify the effects of additional precipitation and N on N2O emissions in temperate grasslands. The results showed that temperate grasslands are a small source of N2O with negative N2O fluxes during the growing seasons. Water addition amplified the variability in N2O fluxes by lowering the mean N2O fluxes and strengthening N2O emission pulses triggered by precipitation. The trade-off between increased N2O emission pulses and decreased mean fluxes resulted in decreased growing season cumulative N2O emissions. The stimulated N2O emissions by N addition were linearly related to N application rates. However, this linear correlation shifted to similar N2O emissions among the N application rates by water addition. In addition, N2O emissions were negatively correlated with soil moisture and microbial biomass carbon (MBC) but positively correlated with soil dissolved organic carbon (DOC), NH4+, and NO3-. Our results suggest that (1) water addition increases the sensitivity of N2O emissions to N addition and limits the loss of additional N as N2O. (2) In addition to directly increasing N2O emissions, N addition increases N2O emissions indirectly by increasing soil DOC, NH4+, and NO3- levels, whereas water addition decreases N2O emissions indirectly by increasing MBC and soil moisture. (3) The ability of soil properties to explain the variability in N2O fluxes was limited, whereas the ability of soil properties to explain the interannual variability in cumulative N2O emissions was highly reliable.