作物水分传输阻力及其通量对水分亏缺的响应机制研究

Deficit irrigation is one of the most promising ways to solve the problem of water resources shortage, but it enables crop withstanding a certain degree of water stress during one or more growth stages. However, the the response mechanism of crop water transport resistance and water transfer flux to water deficit are still inexplicit. Thus, based on the efforts of interdisciplinary and combination of field experiments, theoretical analysis, and crop model evaluation, the objectives of this project were: to interpret the response of crop root growth to soil moisture and dynamic process of root water uptake, and establish a macro root water uptake model considering changes of root hydraulic characteristics; to analyze the responses of crop water transport resistance to soil water status for reveal the relationship between plant hydraulic conductivity and soil moisture under different growth stages; to investigate the variability of crop canopy resistance with soil moisture and clarify the relationships of canopy resistance with leaf area index, stomatal conductance and soil water stress index. Moreover, the canopy resistance estimation model based on the relationship between plant water transport resistance and soil moisture at different growth stages will be explored and established and water flux estimation model based on water transport resistance mechanism will be proposed to optimize. The research production of this project has important theoretical significance and practical application value, which will provide a theoretical basis for field water efficient conversion and crop physiological water-saving, and will enrich and improve the theories of agricultural water conversion and deficit irrigation.

采用非充分灌溉是应对水资源短缺的重要措施，但会使作物在某个或某些生长阶段经受一定程度的水分亏缺，而对于作物水分传输阻力及水分传输通量对水分亏缺响应机制这一科学问题研究还不够。本项目从多学科交叉的角度出发，采用试验研究、理论分析与模型验证相结合的方法，研究作物根系生长的水分响应及根系吸水的动态变化，建立考虑根系水力特性变化的宏观根系吸水模型；研究作物体内水分传输阻力对土壤水分状态的响应，建立不同生育期植株导水率与土壤水分的关系；研究作物冠层导度的水分响应规律，揭示冠层导度与作物叶面积指数、气孔导度、土壤水分胁迫指标之间的关系；探索建立基于不同生育期植株水分传输阻力与土壤水分关系的冠层导度估算模型，改进基于水分传输阻力的农田水分通量估算模型。研究成果将为实现农田水分的高效转化利用和作物生理节水提供理论依据，丰富和完善农业水转化与非充分灌溉理论，项目具有重要的理论意义和实际应用价值。

采用非充分灌溉是应对水资源短缺的重要措施，但会使作物在某个或某些生长阶段经受一定程度的水分亏缺，而对于作物水分传输阻力及水分传输通量对水分亏缺响应机制这一科学问题研究还不够。按照课题申请书的研究内容及研究计划，本项目从多学科交叉的角度出发，采用试验研究、理论分析与模型验证相结合的方法，开展了亏缺灌溉条件下作物根系生长、作物水分传输阻力、农田水碳通量变化以及农田水分通量估算模型模拟等方面的研究。取得了以下主要成果：揭示了作物根系生长的水分响应及根系吸水的动态变化规律，建立了作物根系吸水的简易估算模型；明确了作物水分传输阻力对土壤水分状态的响应规律，确定了水分传输阻力与土壤水分的关系；探明了作物冠层导度与作物冠层表面参数、作物叶面积指数、作物系数、饱和水汽压差等指标之间的关系；阐明了冬小麦、夏玉米农田水碳通量的年际年内变化特征及农田水分通量对亏缺灌溉的响应规律；基于SPAC水分传输系统，构建了SCOPE_STEMMUS耦合模型，准确模拟估算了当地农田水碳通量。研究结果为实现农田水分的高效转化利用和作物生理节水提供了理论依据，丰富和完善了农业水转化与非充分灌溉理论。本研究以国家自然科学基金项目（51879223）为标注，发表学术论文 38 篇，其中 SCI 收录 22 篇，EI 收录 4 篇，项目实施以来先后培养博士后1名，毕业博士研究生 5 名，毕业硕士研究生10 名。