开垦对放牧温性草原生态系统水分利用效率的影响  

Effects of grassland cultivation on ecosystem water use efficiency in a grazed temperate grassland area

作　　者：李愈哲[1] 邵全琴[1] 樊江文[1] 陈一 陈智 官惠玲 张馨元 LI Yu-zhe;SHAO Quan-qin;FAN Jiang-wen;CHEN Yi;CHEN Zhi;GUAN Hui-lin;ZHANG Xin-yuan(Key Laboratory of Land Surface Pattern and Simulation,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;Key Laboratory of Ecosystem Network Observation and Modeling,Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101,China;China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国科学院地理科学与资源研究所陆地表层格局与模拟重点实验室,北京100101 [2]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室,北京100101 [3]中国地质大学,北京100083

出　　处：《草业学报》2019年第10期110-121,共12页Acta Prataculturae Sinica

基　　金：国家重点研发计划(2017YFA0604801,2017YEC0506500);国家自然科学基金项目(41601615)资助

摘　　要：作为生态系统碳水循环的耦合指标,水分利用效率(WUE)是衡量区域资源转化效率的重要参考。为了解开垦利用对放牧草地生态系统水分利用效率的影响,以放牧区域和开垦利用区域毗邻的两套涡度相关系统监测数据为基础,结合群落调查和采样测定,对比分析了两种管理利用方式下生态系统水分利用效率(WUE GPP)的动态差异和影响因素。结果显示:1)WUE GPP在夏季达到全年峰值,6月开垦站点日均WUE GPP 3.61 g C·kg-1 H 2O,较放牧站点高58%,全年WUE GPP 3.07 g C·kg-1 H 2O,较放牧站点2.11 g C·kg-1 H 2O提升约50%;2)开垦站点较高的WUE GPP归咎于生长季较高的总初级生产力(GPP)和非生长季更低的蒸散耗水(ET);3)ET变化对放牧站点WUE GPP变异解释程度较高(26%,P<0.001),而GPP对开垦站点WUE GPP变化的解释程度(45%,P<0.001)高于ET;4)环境因子中,土壤含水量对WUE GPP变化的调控作用最强,两者负相关关系在开垦站点、放牧站点均达到极显著水平(P<0.001)。研究结果能为合理规划区域土地利用,促进干旱区关键资源高效利用提供有益参考。Water use efficiency(WUE)is an indicator of coupling between ecosystem carbon and water cycles,so it is an important reference for the measurement of regional resource transformation efficiency.The purpose of this study was to determine the effects of cultivation on the WUE of a grazed grassland ecosystem.On the basis of the vorticity-related system monitoring data in adjacent grazed and cultivated areas and combined community investigations and sampling measurements,this study analyzed the dynamic difference and effects of two different management patterns on the WUE of the ecosystem(gross primary productivity;GPP)(WUE GPP).The results indicated that:1)WUE GPP reached its peak each year in summer;in June,the daily average WUE GPP of the cultivated sites(3.61 g C·kg-1 H 2O)was 58%higher than that of the grazed sites,and the annual WUE GPP of the former(3.07 g C·kg-1 H 2O)was 50%higher than that of the latter.2)The higher WUE GPP of the cultivated sites was due to the higher GPP during the growing season and lower evapotranspiration(ET)during the non-growing season.3)The ET explained the change in the WUE GPP of the grazed sites(26%,P<0.001),while GPP explained the change in WUE GPP of the cultivated sites(45%,P<0.001)better than did ET.4)Among the environmental factors,soil moisture had the strongest effect on the change in WUE GPP and the negative correlation between them was extremely significant both for the cultivated and grazed sites(P<0.001).These results show that different land management practices and utilization types can significantly affect ecosystem WUE on the temperate steppe.Among the various environmental factors,soil water content explained the changes in WUE GPP at both the grazed and cultivated sites,and so soil water supply may be the most important factor regulating WUE in regional ecosystems.These results provide a useful reference for scientific planning of regional land use and for the reinforcement of more efficient use of key resources in arid areas.

关 键 词：草地开垦 放牧生态系统 草地利用方式转变 温性草原 水分利用效率 

分 类 号：Q94[生物学—植物学]