调亏灌溉对冬小麦根系水氮吸收的调控机理及模拟研究

Water and nutrient uptake of crop depends on root system, and its absorptive ability directly determines crop growth and development and yield formation. The main grain crop-winter wheat of the Huang-Huai-Hai Plain is choosen as study object, and a combination method of simulation and field trial adopt. The project mainly studies the effect of regulated deficit irrigation on dynamics of root and shoot growth, accumulation and partitioning of photosynthates and physiological and physiochemical characteristics of winter wheat; development of a coupled model of water, heat and nitrogen transport with crop growth, and simulation and analysis of soil water and heat dymamics, nitrogen transport, crop yield, and water and nitrogen use efficiency of winter wheat with regulated deficit irrigation; regulation mechanism of regulated deficit irrigation on root absorptive ability of water and nitrogen. Simulaiton of crop growth and development and the porcesses related to accumulation and partitioning of photosynthates under water dificit and development of a coupled model of water, nitrogen transport with crop growth is the key problem of this project. Root absorptive ability of water and nitrogen as a breakthrough point and a contacting point, to study regulation characteristics of regulated deficit irrigation on wheat dynamics of root and shoot growth, accumulation and partitioning of photosynthates, crop yield, and water and nitrogen use efficiency. It has significant meaning to further in-depth understanding water and nitrogen utilization process of winter wheat, and enrichment and development the theory of regulated deficit irrigation.

作物对水分和养分的吸收主要依赖于根系，其吸收能力直接决定植株的生长发育和产量的形成。本项目以冬小麦为研究对象，采用田间试验和实验室化验分析并结合数值模拟的研究方法，重点研究调亏灌溉对冬小麦根、冠生长、生理生化特性以及光合产物积累与分配的影响；构建土壤-作物系统水、氮运移及作物生长联合模拟模型，模拟分析土壤-作物系统中水、氮去向、作物产量构成和水、氮利用效率对调亏灌溉的响应过程；揭示调亏灌溉对冬小麦根系水、氮吸收能力的调控机理。解决的关键问题是探明冬小麦生长发育进程、光合产物积累和分配对水分胁迫的响应过程，以及作物生长联合模拟模型的构建与相应参数的确定。本项目研究前瞻性在于，以根系水、氮吸收能力为突破口和切入点，研究模拟冬小麦生长、光合产物积累和分配、水、氮吸收利用以及产量形成对水分胁迫的自身调控特性，对进一步深入认识冬小麦水、氮利用过程以及丰富调亏灌溉理论有着重大意义。

本项目研究了调亏灌溉对冬麦根冠生长发育、植株生理生化指标以及冬小麦产量和品质指标的影响规律。返青拔节期轻度水分调亏抑制了冬小麦株高和前期叶面积和地上部生物量的生长发育，但恢复供水后冬小麦叶面积生长发育和地上部生物量积累均表现出超补偿效应。与对照处理相比，返青拔节期、抽穗扬花期和灌浆成熟期轻度亏水处理的根冠比分别增加了4.5%、2.87%和5.80%；重度调亏处理根/冠比分别增加了11.76%、5.74%和7.59%。.在调亏阶段冬小麦叶片光合速率随亏水强度的增加呈下降趋势，恢复供水后冬小麦叶片光合速度率普遍大于对照处理，但抽穗扬花期水分调亏处理的亏水补偿效应小于返青拔节期水分调亏。与对照处理相比，返青拔节期轻度和重度水分调亏处理冬小麦叶片气孔导度的平均值分别降低了20.07%和35.98%；灌浆期轻度和重度水分调亏处理的平均值分别降低了18.41%和36.04%。.与对照处理相比，返青~拔节期和灌浆成熟期轻度亏水处理的籽粒产量分别提高了0.19%和-2.31%；其他水分亏缺处理均不同程度的降低了籽粒产量。抽穗扬花期和灌浆成熟期水分亏缺，有利于提高冬小麦籽粒粗蛋白质质量分数、氨基酸质量分数、湿面筋质量分数、降落值、面团形成时间和面团稳定时间。.返青拔节期和灌浆成熟期轻度水分调亏有利于冬小麦籽粒产量和水分利用效率的提高。返青拔节期和灌浆成熟期轻度水分亏缺对氮肥生产效率的影响较小，而抽穗扬花期水分胁迫对冬小麦氮肥生产效率的负面影响较大，特别是抽穗扬花重度水分胁迫处理的冬小麦氮肥生产效率比对照处理降低了61.90%。.构建了适用于调亏灌溉条件下冬小麦生长模型，通过田间试验验证，利用该模型模拟的冬小麦生育期进程、叶面积指数和地上部生物量、冬小麦籽粒产量以及收获时冬小麦植株和籽粒中氮素积累量与实测值比较接近，模拟值和实测值两个变量的相关系数均超过了0.8。