农业干旱对华北平原农业生态系统碳通量的影响  

The Effects of Agricultural Drought on Agro-ecosystem Carbon Fluxes in the North China Plains

作　　者：王楠 辜玉慧 马孝义[1,2] WANG Nan;GU Yu-hui;MA Xiao-yi(College of Water Resources and Architectural Engineering,Northwest Agricultural and Forestry University,Yangling 712100,Shaanxi Province,China;Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas,Ministry of Education,Northwest Agricultural and Forestry University,Yangling 712100,Shaanxi Province,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]西北农林科技大学旱区农业水土工程教育部重点实验室,陕西杨凌712100

出　　处：《中国农村水利水电》2023年第9期75-83,共9页China Rural Water and Hydropower

基　　金：国家自然科学基金项目(52179048);国家重点研发计划(2021YFD1900600)。

摘　　要：农业是全球生态系统碳循环的重要组成部分,受干旱影响较大,因此了解干旱对农业生态系统碳汇强度的影响有助于理解农业生态系统碳循环的变化规律,为实现碳排放的控制提供理论依据。利用植被光合呼吸模型(VPRM)对华北平原冬小麦-夏玉米轮作系统净生态系统碳交换量(NEE)进行模拟,基于蒸散发和归一化植被指数计算干旱严重程度指数(DSI)作为评价农业干旱强度的指标,并通过地理探测器和去趋势分析评估了华北平原农业生态系统NEE对农业干旱的时空响应。结果表明,冬小麦生育期间华北平原北部农业干旱强度大于南部,且随着冬小麦发育,其农业干旱强度逐渐降低;夏玉米生育期间,华北平原进入雨季,整体较为湿润。农田生态系统固碳能力随着农业干旱强度的增加而减小,且农田生态系统NEE对农业干旱的敏感性在冬小麦/夏玉米生育中期大于生育初期和末期,其中农业干旱的空间变异性对冬小麦NEE的解释力在3月最大(q=0.681),对夏玉米NEE的解释力在8月最大(q=0.792)。随着农业干旱强度的加重,若不考虑籽粒碳含量,麦田和玉米田从强碳汇变为弱碳汇,若考虑籽粒碳含量,则其最终转变为碳源。Agriculture is an important part of the global ecosystem carbon cycle,which is greatly affected by drought.Therefore,understand⁃ing the impact of drought on the carbon sink intensity of agro-ecosystems helps to figure out the change regular of agro-ecosystem carbon cy⁃cle and provide a theoretical basis for realizing the control of carbon emissions.In this paper,the net ecosystem exchange(NEE)of winter wheat-summer maize rotation system in North China Plains is simulated by vegetation photosynthesis and respiration model(VPRM),and Drought Severity Index(DSI)is calculated based on evapotranspiration and normalized vegetation index to evaluate the agricultural drought intensity.The spatiotemporal response of NEE to agricultural drought is also assessed by using geographic detectors and de-trended analysis.The results show that the agricultural drought intensity in the northern part of North China Plains is more than that in the southern part of North China Plains during the growth period of winter wheat,and the agricultural drought intensity gradually decreases with the development of winter wheat.During the growth period of summer maize,North China Plains enters the rainy season and is generally wet.The carbon se⁃questration capacity of cropland ecosystem decreases with the increase in agricultural drought intensity,and the sensitivity of NEE of crop⁃land ecosystem to agricultural drought is greater in the middle growth stage of winter wheat/summer maize than in the early and late growth stages.The spatial variability of agricultural drought has the largest explanatory power for NEE of winter wheat in March(q=0.681).The ex⁃planatory power for NEE of summer maize is the highest in August(q=0.792).With the increase in agricultural drought intensity,wheat and maize fields change from strong carbon sink to weak carbon sink if grain carbon content is not considered,and finally change to carbon source if grain carbon content is considered.

关 键 词：农业干旱 碳通量 华北平原 冬小麦 夏玉米 

分 类 号：S166[农业科学—农业气象学]