遥感-作物模型耦合土壤多层水平衡与根系垂直分布模拟干旱对作物产量的影响

North China is crop planting area, where is affected by the severe drought disaster; it is very important to accurately simulate water stress on crop growth and yield under drought at different growth stages; Among these, the layered soil moisture and vertical root distribution characteristics are important parameters which accurately reflect the crop response to drought stress. In this study, we select crop area of winter wheat in North China as study area and carry out field experiment. Firstly, the single layer soil water balance model in existing remote sensing -photosynthetic -yield estimation for the crops model (RS-P-YEC) will be replaced by a multilayer water balance module, which can accurately simulate the diurnal changes of soil moisture in different depth; Secondly, to study the root distribution in multilayer soil at different growth period, we will establish the quantitative correlation between winter wheat root system, soil water and plant water stress situation, and develop a module for representing the relationship among root distribution - crop growth stage-remote sensing data, so as to describe the time series continuous distribution of winter wheat roots in regional scale for the accurate estimation of winter wheat growing under water stress conditions; And the developed water stress parameter estimation module of stomatal conductance (GS) will be coupled with RS-P-YEC model, we simulate the effect of drought on crop yield; and analyze developed RS-P-YEC model in response to drought stress in different growth stages of winter wheat and study how sensitivity to the continuous and intermittent drought events, and quantitatively discuss the effects of different degree of water stress on yield of winter wheat in different growth stages. The result will provide an assessing method to effectively simulate the loss of winter wheat yield under drought.

华北平原是受干旱影响严重的作物种植区，准确模拟干旱下水分胁迫对作物生长和产量影响具有重要意义，而分层土壤湿度和根系垂直分布是准确反映作物对干旱胁迫响应的重要特征参数。本项目以华北冬小麦农田为试验区，改进现有区域遥感光合作物产量模型（RS-P-YEC）的单层土壤水平衡模型至多层水平衡模型，使其能准确模拟日尺度不同深度土壤湿度；研究不同生育期根系在土壤层分布状况，发展“根系分布-生育期-遥感数据”关系表征模型，以期在区域尺度刻画连续时间序列的小麦根系分布，建立小麦根系、土壤水与植株水分胁迫之间的定量关系，以期准确估计冬小麦受水分胁迫状况。基于改进的水分胁迫参数模块估算气孔导度（GS）并耦合到RS-P-YEC模型中；研究改进模型对不同生育期干旱胁迫响应，及对历史年份发生持续性和间歇性干旱的敏感性；定量探讨不同生育期不同水分胁迫程度对冬小麦产量影响程度,为准确模拟干旱对冬小麦产量提供模型方法。

随着全球变化和人类活动影响，华北平原农田生态系统干旱状况呈现加重趋势，灌溉用水严重不足，准确模拟干旱下水分胁迫对作物生长和产量影响具有重要意义.以往模型模拟产量方面，考虑土壤-植被-大气过程的连续性不足，发展分层土壤湿度和根系垂直分布，提供一种准确刻画作物光合生长、根层吸水、作物蒸散生理过程对干旱胁迫响应的过程至关重要。.近年来，华北平原是受干旱影响严重，出现作物生长发育不良，导致作物产量波动，因此，准确模拟干旱下水分胁迫对作物生长和产量影响具有重要意义，其中，准确地定量化构建分层土壤湿度和根系垂直分布可以准确反映作物对干旱胁迫响应。本研究以华北冬小麦农田为研究区，基于区域遥感光合作物产量模型（RS-P-YEC），改进了单层土壤水平衡模型至多层水平衡模型，使其能准确模拟日尺度不同深度土壤湿度；通过构建不同生育期根系在土壤层分布状况函数，发展“根系分布-生育期-遥感数据”关系表征模型，建立小麦根系、土壤水与植株水分胁迫之间的定量关系，以期准确估计冬小麦受水分胁迫状况。进一步基于对蒸发过程模型的改进，构建水分胁迫参数模块，以估算气孔导度（GS）和发展灌溉水分动态模块并耦合到RS-P-YEC模型中，实现不同土壤层对冬小麦不同生育期干旱胁迫响应过程分析，以及对历史年份发生持续性和间歇性干旱的敏感性；分析多年水分利用效率的动态趋势以便更好干旱对植物生长发育和作物产量的影响和贡献率。探讨不同生育期不同水分胁迫程度对冬小麦产量影响程度,为准确模拟干旱对冬小麦产量提供模型方法。项目执行期间，已发表相关论文 17篇，其中SCI论文13篇，EI1篇， CSCD3篇；培养研究生6名。已经完成相关目标任务。