灌水总量与灌溉技术双重约束下华北井灌区冬小麦灌溉制度多目标协同优化方法研究

As surface irrigation and groundwater are respectively the main irrigation style and the primary irrigation source for planting winter wheat in the well-irrigation areas of North China, the currently burning issue for this area is to improve the water management of surface irrigation and increase irrigation water use efficiency to contain groundwater overexploitation. This research is carried out within the typical well-irrigation areas of North China, with remaining the groundwater level and stabilizing and increasing the winter wheat yield as its control conditions, and raising the crop’s water use efficiency as its optimization objective. This research analyzes and calculates the potential targets of groundwater conservation and compression of groundwater exploitation, and the irrigation quota of the related winter wheat. By using the model tools of crop irrigation, this research proposes the combined scheme to optimize winter wheat irrigation schedule under the limit of the irrigation quota. And by using the numerical simulation models of surface irrigation, this study simulates the effect of the relevant technical factors in surface irrigation on irrigation performance under the optimized irrigation schedule. Finally, a multi-objective optimization model considering numerous relevant irrigation decision variables is built and solved in numerical values for the combined scheme of irrigation optimization under various objectives. This research is expected to propose an optimized irrigation schedule for the winter wheat planting in the well irrigation areas of North China, and an irrigation system layout mode which coordinates with the existing irrigation techniques, to provide the theoretical and technical supports for achieving the goals in conserving groundwater, compressing groundwater exploitation and stabilizing the crop yield in the well-irrigation areas of North China.

地面灌溉和地下水是华北井灌区冬小麦种植的主要灌溉手段及灌溉水源，改进地面灌溉用水管理，提高灌溉水利用效率以遏制地下水超采是华北井灌区当前迫切需要解决的问题。本研究定位于华北井灌区典型区域，以地下水位不继续下降和冬小麦稳产增产为控制条件，以提高作物水分利用效率为优化目标，开展课题研究。分析计算地下水节水压采潜力指标，以及对应的冬小麦灌水定额。应用作物模型工具，提出灌水定额限制下，冬小麦优化灌溉制度设计的方案组合。应用地面灌溉数值模拟模型，模拟优化灌溉制度下，地面灌溉相关技术要素对灌溉性能的影响。最终建立考虑诸多相关灌水决策变量的多目标优化模型，采用数值解法对模型求解，提出不同目标下的灌溉优化方案组合。以期提出华北井灌区冬小麦种植的优化灌溉制度，以及与现有地面灌溉技术相协调的灌溉系统布置模式，为华北井灌区节水压采稳产目标的实施提供理论与技术支持。

华北地区是我国冬小麦的主产区，冬小麦生育期降水很难满足作物需耗水的要求，对灌溉严重依赖，而地面灌溉技术仍是该区域作物灌溉的主要方式。因此，优化作物灌溉制度，改进地面灌溉用水管理，提高灌溉水利用效率是华北地区缓解灌溉水资源供需矛盾所迫切需要解决的问题，也是实现用水总量控制的最主要途径，而其核心内容就是灌水技术的提高和灌溉制度的改进。本研究基于大量田间试验观测数据，分析研究区农业灌溉用水与地下水位变化的响应关系，综合确定冬小麦合理的灌溉定额。应用DSSAT作物生长模型进行模型参数估计，采用交叉验证方法，对模型适用性进行评价，构建研究区冬小麦受试作物品种参数库。应用SISM地面灌溉水流运动模拟模型，进行研究区畦灌一维水流运动数值模拟，对模型适用性进行评价，获取并评价畦灌技术要素和灌水性能指标值的对应关系，建立对应数据库，并根据畦灌要素的技术组合条件，确定地面灌溉性能约束下的最小灌水定额。基于作物生长模型参数，以研究区灌溉定额控制指标为上限，地面灌溉性能约束下的最小灌水定额为下限，结合不同降水水平年、作物生育期、畦灌布置方案，确定灌溉制度模拟情景方案，应用作物生长模型进行模拟，分析不同降水年型、生育阶段、灌水定额、灌溉定额与作物模拟产量、蒸发蒸腾量之间的响应关系。基于模拟结果，从作物产量-水分利用效率，及生产净收益-投入产出比两个层面，提出并构建灌溉制度评价及筛选的指标体系及评价模型，对模拟方案进行评价及筛选，最终确定不同降水水平年、地面灌溉田间工程布置方案下的最优灌溉制度，以及与其适应的畦灌田间组合要素。论文研究的成果，对于从整体上缓解灌溉水资源短缺的矛盾，促进华北地区现代农业的可持续发展，具有重要的现实意义。