Water-carbon coupling modeling of summer maize at the leaf and canopy scales  

作　　者：ZHANG BaoZhong LIU Yu XU Di CAI JiaBing WEI Zheng 

机构地区：[1]State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research [2]National Center of Efficient Irrigation Engineering and Technology Research-Beijing [3]Department of Soil and Water Sciences, College of Resources and Environment, China Agricultural University

出　　处：《Chinese Science Bulletin》2013年第27期3361-3370,共10页

基　　金：supported by the National Natural Science Foundation of China (51009151,51109225 and 91125017);the National Basic Research Program of China (2006CB403405);the Special Scientific Fund sponsored by IWHR for Department of Irrigation and Drainage (1209)

摘　　要：Transpiration and photosynthesis are two closely related and intercoupled processes that dominate the physiological activities and yield of crops. Therefore, there is a need to study water-carbon coupling modeling at various scales to increase water use efficiency (WUE). Using a summer maize field in North China as an example, the variations in leaf and canopy photosynthesis and transpiration (or evapotranspiration) were analyzed. The synthetic model of photosynthesis-transpiration based on stomatal behavior (SMPT-SB) was then calibrated and validated at the two scales. The leaf photosynthesis and transpiration, as well as the canopy photosynthesis and evapotranspiration, have a consistent diurnal trend. However, the canopy evapotranspiration is affected more by topsoil moisture content. The regression coefficient between leaf photosynthesis, transpiration, and WUE estimated by the SMPT-SB and the measured values was found to approach 1, with a coefficient of determination of more than 0.74. The relative error between the two sets of values is less than 11%. Therefore, the SMPT-SB could express fairly well leaf photosynthesis, transpiration, and WUE. The estimated canopy-scale photosynthesis by the SMPT-SB is also in good agreement with the measured values. However, this model underestimates the canopy evapotranspiration when the topsoil has high moisture content and therefore overestimates, to a certain extent, the canopy WUE.Transpiration and photosynthesis are two closely related and intercoupled processes that dominate the physiological activities and yield of crops. Therefore, there is a need to study water-carbon coupling modeling at various scales to increase water use efficiency （WUE）. Using a summer maize field in North China as an example, the variations in leaf and canopy photosynthesis and transpiration （or evapotranspiration） were analyzed. The synthetic model of photosynthesis-transpiration based on stomatal behavior （SMPT-SB） was then calibrated and validated at the two scales. The leaf photosynthesis and transpiration, as well as the canopy photosynthesis and evapotranspiration, have a consistent diurnal trend. However, the canopy evapotranspiration is affected more by topsoil moisture content. The regression coefficient between leaf photosynthesis, transpiration, and WUE estimated by the SMPT-SB and the measured values was found to approach 1, with a coefficient of determination of more than 0.74. The relative error between the two sets of values is less than 11%. Therefore, the SMPT-SB could express fairly well leaf photosynthesis, transpiration, and WUE. The estimated canopy-scale photosynthesis by the SMPT-SB is also in good agreement with the measured values. However, this model underestimates the canopy evapotranspiration when the topsoil has high moisture content and therefore overestimates, to a certain extent, the canopy WUE.

关 键 词：冠层光合作用 水分利用效率 耦合建模 玉米叶片 叶片光合作用 蒸腾作用 土壤水分含量 碳 

分 类 号：S513[农业科学—作物学]