灌区水资源高效利用临界特性及其调控机制研究

The main factors restricting the grain production and the sustainable development of agriculture include water shortage under drought conditions, low efficiency of water use and degradation of water and soil environment. The mechanism of water conversion as well as its corresponding effects on grain production and environment in irrigation area, are the cutting-edge research topics in the international water conservancy engineering. This project will focuse on the characteristic,motivation mechanism and simulation models of water potential conversion among field-channel-ditch-pond-reservoir in southern hilly irrigation areas, by experiments of water potential monitoring and irrigation drainage control on various objects in the different places. A quantitative method to define the general water potential will be discussed and then a general water potential model for the realization to the high efficiency of water use will be established by dynamic monitoring the water flow and investigation on agricultural production economic market. Also, the balance mechanism of water potential between the fields,channels,ditches,ponds and reserviors, the efficiency improvementits as well as its effects on grain production and environment in the complicated irrigation and drainage system will be simulated and analyzed. Besides, regulatory means and their corresponding critical conditions as well as the standards for high efficiency water use at different scales will be presented. Therefore, it will have great significance in theoretical research and broad prospect in practical application to solve difficult problems in the water use mode and the mechanism of regulation, to improve irrigation water use efficiency, to develop new theory and methods for high efficiency water use, to establish the strictest water resources management system, to prevent agricultural drought and non-point source pollution, to maintain ecological balance and to realize the modernization and ecological civilization in irrigation areas.

干旱缺水、用水效率低下与水土环境退化，是制约粮食生产与农业可持续发展的主要因素。灌区水转化机理及其产量环境效应，是国际农业水利领域共同关注的前沿焦点问题。本项目以南方丘陵平原灌区为背景，通过灌区不同地理位置对象的农田水势监测及灌排水位水量调控试验，研究农田、灌排沟渠、水库塘堰之间水势转化关系及其系统模拟模型、临界特性；通过自然水流场动态监测与农业生产经济场调查，探讨灌区广义水势定量描述方法，构建基于广义水势的灌区水资源高效利用调控模型，模拟分析沟渠塘库系统优化调控规则及效率响应规律，提出灌区水资源高效利用的灌排经济模式及其调控机制、条件与技术标准。对解决我国南方灌区复杂条件下的水转化及水资源高效利用调控机制等难点问题，提高灌溉水利用效率，创新发展农业水资源高效利用理论与方法，建立最严格的水资源管理制度，防治水旱灾害与非点源污染，维持生态平衡，实现灌区现代化，具有重要理论意义与广泛应用前景。

本项目以我国南方丘陵平原过渡带湖北漳河水库灌区为背景，以节灌控排与农业生产变化为条件，以农田水势、沟渠水位、灌排水量之间转化关系为主线，釆用实地查勘、灌排试验、区域监测、理论分析、模型构建、数值模拟、统计归纳相结合的研究方法，开展灌区水资源高效利用临界特性及调控机制研究。阐述了旱作水稻产量因子对水分胁迫的响应规律，揭示了旱作水稻控势灌溉机制，提出了以土水势为灌溉控制指标的水稻旱作模式以及考虑生物多样性条件下的田间需水量阈值。通过开展田间-渠系-灌区多尺度水平衡要素监测，揭示了长藤结瓜灌溉系统农田与区域不同尺度水转化效率的差异原因及其规律，基于系统动力学原理描述了稻田塘堰系统水转化过程，提出了农业用水效率考核新指标“千公顷灌溉取水量”的概念，给出了相应的计算依据、方法及适用条件。针对灌区供水水源、作物种植结构多样的特点，研究多水源联合供水控制方案优化及其失效风险，建立库塘联合调控与作物优化分配耦合模型，采用粒子群-人工蜂群混合算法有利于求解多水源优化调控问题。考虑农业水资源管理中存在的不确定性和动态因素，通过融合多阶段随机规划和区间参数规划，提出了一种区间多阶段水量分配模型。通过非一致性分析和模型优化，提出了一种能解决水资源管理中的非一致性、不确定性、动态性和复杂性问题的新方法。运用水资源系统分析与经济学理论，建立了基于供求关系和生产函数的灌区水量使用权交易模型。研究为揭示灌区水转化过程及其高效利用调控机制，提出保障粮食生产、实现生态高效的现代化灌区建设和农业可持续发展措施对策，提升水安全保障能力，具有十分重要的科学意义。