中国草地学报2025，Vol.47Issue(12)：47-56,10.DOI:10.16742/j.zgcdxb.20250171
降水变化对荒漠草原灌丛人为转变过程土壤氮矿化的影响趋势
Effects of Precipitation Variation on Soil Nitrogen Mineralization during Shrub Encroachment in Desert Steppe
摘要
Abstract
This study investigated soil nitrogen mineralization responses to precipitation changes during the anthropogenic grassland-shrubland transition in the eastern desert steppe of Ningxia.A controlled litter-water manipulation experiment was conducted,including three litter treatments(grass,shrub,CK)and two precipitation treatments(+40%and-40%),to assess soil nitrogen mineralization patterns under dif-ferent simulated precipitation regimes.The results showed that compared with grass litter,the soil micro-bial biomass nitrogen in desert grassland and grassland edge soils were more sensitive to shrub litter under high precipitation conditions,and in shrubland the soil microbial biomass nitrogen was more sensitive to shrub litter under reduced precipitation(P<0.05).Under increased precipitation,shrub litter led to an increasing trend in soil ammonium nitrogen and net ammonification rates significantly increased during the transition(P<0.05),whereas soil microbial biomass carbon,microbial biomass nitrogen,and nitrate nitrogen along with its mineralization rate declined.Under reduced precipitation,soil nitrate nitrogen and net nitrification rates increased,and microbial biomass carbon and nitrogen in shrubland were significantly higher than those in desert steppe(P<0.05).Throughout the transition process,the soil inorganic nitro-gen and its mineralization rate were significantly affected by both litter type and precipitation(P<0.05).Among these factors,the positive effect of increased precipitation on ammonium nitrogen was greater than that of litter,whereas nitrate nitrogen and net nitrification rate were primarily regulated by litter type(P<0.05).In conclusion,shrub litter exerted a markedly stronger stimulatory effect on soil nitrogen mineraliza-tion than grass litter,thereby playing a dominant role in soil nitrogen cycling during grassland-shrubland transition.Specifically,under higher precipitation,shrub litter mainly enhances soil ammonification(NH+4 accumulation),while under reduced precipitation,nitrogen mineralization shifted toward a nitrification-dominated pathway(NO-3 generation).关键词
荒漠草原/灌丛化/土壤氮矿化/降水变化/枯落物添加Key words
Desert steppe/Shrub encroachment/Soil nitrogen mineralization/Precipitation change/Litter addition分类
农业科技引用本文复制引用
LIU Mengdi,WANG Hongmei,LI Zhili,ZHANG Zhenjie,ZHAO Xiaoyu,LI Aotian..降水变化对荒漠草原灌丛人为转变过程土壤氮矿化的影响趋势[J].中国草地学报,2025,47(12):47-56,10.基金项目
宁夏自然科学基金项目(2024AAC03127,2025AAC0-50023) （2024AAC03127,2025AAC0-50023）
国家自然科学基金项目(32401433,31860677) （32401433,31860677）
宁夏高等学校一流学科建设项目(NXYLXK2017A01) （NXYLXK2017A01）
