title: Effects of Simulated Nitrogen Deposition on Soil Net Nitrogen Mineralization in the Meadow Steppe of Inner Mongolia, China.
abstract: Effects of simulated nitrogen (N) deposition on soil net nitrogen mineralization (NNM) were examined in situ during two growing seasons, using the resin-core technique in the semiarid meadow steppe in Inner Mongolia, China. The aim of this study is to clarify the effect of N levels (0, 10, and 20 kg N ha-1yr-1) and forms (NH4+ and NO3-) on soil mineral N and NNM. Our results showed that N levels had no significant differences on soil mineral N and NNM. In the first year, three N treatments ((NH4)2SO4, NH4Cl and KNO3) increased soil NH4+ concentrations but had no significant effects on soil NO3- concentrations. In the second year, (NH4)2SO4 treatment increased soil NO3- concentrations, NH4Cl and KNO3 treatments decreased them. Three N treatments significantly decreased soil NH4+ concentrations in the later stages of the second year. As for the soil NNM, three N treatments had no significant effects on the rates of soil NNM (Rm) and net nitrification (Rn) in the first year, but significantly decreased them in the second year. The contribution of N addition to Rm was higher from (NH4)2SO4 than from NH4Cl and KNO3. However, Soil Rm was mainly affected by soil water content (SWC), accumulated temperature (Ta), and soil total N (TN). These results suggest that the short-term atmospheric N deposition may inhibit soil NNM in the meadow steppe of Inner Mongolia.
authors.affiliation: Agricultural Clear Watershed Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agricultural Environment, Ministry of Agriculture, P. R. China.
authors.forename: Xing-Ren
authors.initials: XR
authors.lastname: Liu
authors.affiliation: Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Ren
authors.affiliation: Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Sheng-Gong
authors.initials: SG
authors.lastname: Li
authors.affiliation: Agricultural Clear Watershed Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agricultural Environment, Ministry of Agriculture, P. R. China.
authors.forename: Qing-Wen
authors.initials: QW
authors.lastname: Zhang
mesh_terms: D018533:Biomass; D002681:China; D003198:Computer Simulation; D017753:Ecosystem; D004784:Environmental Monitoring; D008903:Minerals / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry*; D012621:Seasons; D012987:Soil / Q000737:chemistry*
chemical_list: D008903:Minerals; D012987:Soil; D009584:Nitrogen