文献类型：期刊文献

英文题名：Effect of grazing on the abundance of functional genes associated with N cycling in three types of grassland in Inner Mongolia

作者：Ding, K.[1] Zhong, L.[2] Xin, X. P.[3] Xu, Z. H.[4] Kang, X. M.[5] Liu, W. J.[1] Rui, Y. C.[6] Jiang, L. L.[7] Tang, L.[1] Wang, Y. F.[1]

第一作者：Ding, K.

通信作者：Wang, YF[1]

机构：[1]Univ Chinese Acad Sci, Coll Life Sci, Beijing 100049, Peoples R China;[2]Tianjin Univ, Sch Environm Sci & Engn, China Australia Ctr Sustainable Urban Dev, Tianjin 300072, Peoples R China;[3]Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, Beijing 100081, Peoples R China;[4]Griffith Univ, Environm Futures Ctr, Brisbane, Qld 4111, Australia;[5]Chinese Acad Forestry, Inst Wetland Res, Beijing 100091, Peoples R China;[6]Univ Western Australia, Sch Earth & Environm, Crawley, WA 6009, Australia;[7]Chinese Acad Sci, Inst Tibetan Plateau Res, Lab Alpine Ecol & Biodivers, Beijing 100101, Peoples R China

年份：2015

卷号：15

期号：3

起止页码：683-693

外文期刊名：JOURNAL OF SOILS AND SEDIMENTS

收录：;Scopus(收录号：2-s2.0-84925496733);WOS:【SCI-EXPANDED(收录号:WOS:000349605100018)】；

基金：This study was supported by the National Sciences Foundation of China (30830026), the Knowledge Innovation Program of the China Academy of Science (Y12501BES2), and the National Youth Science Foundation of China (grant no. 31300417).

语种：英文

外文关键词：Grazing; Nitrogen cycling; pH; Precipitation gradient; qPCR; Soil moisture

摘要：The aim of the study was to investigate the patterns of soil nitrogen (N)-cycling functional gene abundance along a precipitation gradient on the Mongolian Plateau, and the effects of grazing on the population size of microbial functional group under different precipitation regimes. Soil samples were taken from grazing and non-grazing plots of meadow steppe, typical steppe, and desert steppe plots on the Mongolian Plateau for soil gravimetric moisture content, pH, and soil organic carbon (SOC), total N, and inorganic N (NH4 (+)-N and NO3 (-)-N) concentrations, and the abundance of functional genes associated with N-2 fixation (nifH gene), nitrification (AOA and AOB genes), and denitrification (narG, nirS, nirK, and nosZ genes) was studied. The relationships between environmental variables, soil physicochemical properties, and functional microbial abundance were examined. Soil properties (soil moisture, pH, soil organic carbon, total nitrogen, NH4 (+)-N, and NO3 (-)-N content) and abundance of N-cycling groups all varied with precipitation. Compared with desert steppe, precipitation significantly decreased the abundance of nifH gene by 1 order of magnitude, but markedly increased the abundance of AOA and AOB genes by 1.32 to 4.72 times and denitrifying genes narG, nirS, nirK, and nosZ by 0.66 to 9.02 times in meadow steppe. Grazing significantly decreased the abundance of functional groups in desert steppe and typical steppe (p < 0.001), while there was no difference between grazing and non-grazing treatments in meadow steppe which had the highest precipitation level. Soil pH was the main factor affecting the abundance of nifH gene according to simple linear regression (R (2) = 0.934, p < 0.001), while moisture was positively related with population sizes of nitrifier and denitrifier groups, explaining 53.8-92.34 % of the variation in the abundance of AOA, narG, nirS, and nosZ genes in all three steppes. Soil pH was the major factor that significantly affected the gene abundance of nitrogen fixation process, and soil moisture was the dominant factor controlling the gene abundance of nitrification and denitrification process along the precipitation gradient. Grazing had no effect on the gene abundance of N-cycling process in meadow steppe but decreased it in desert and typical steppe. Our results suggest that grazing may not necessarily be associated with a reduction in microbial functional potentials when soil moisture was relatively good but will decrease the soil microbial functional potentials in a more arid environment in northern China grasslands.