气候变化背景下挠力河流域耕地利用变化水土资源平衡效应研究

How to adapt to climate change, spatiotemporal coupling the water and land resources and explore our grain yield potential, is not only one of the key issues of global change adaptation research, but also the current agricultural soil and water engineering, land resource utilization and hydro-geological problems to be solved. The Naoli River Basin has been a typical grain output base since 90s of last century, the increasing of the quantity of cultivated land and the internal structure adjustment are seriously driven by the "climate- policy-human activities", and a series of uncoordinated problems about utilization of water and soil resources have happened, then it is urgent to adjust the cultivated land in order to achieve the balance of water and land resources.The project is a major practical requirement of comprehensive response to water and land resources balance under the climate change, coupling the water and land resources in the view of natural, artificial and policy as the main research idea, and then following the "Process - Mechanism - Impact - Regulation" ideas, and multidisciplinary theory method basis, the project will divide farmland types in dryland, irrigated, irrigation canal and well irrigation paddy fields, extract and analyze Naoli River Basin the process of paddy field expansion since the 1990s, and analyze the driving mechanism of evolution of Cultivated Land based on system theory and then constructing the water and land resources balancing theory on natural- artificial- policy view, and research driving mode overall, research the land and water resources balance effect from the view of farmland water balance, the land resources responses under the water use and its external influences and effects to achieve the adjustment of cultivated land and make final land and water resources adaptation strategies. The project will deepen the study of water and land resources balancing effects under the global warming in equilibrium, promote the development and construction of modern agriculture comprehensive reform pilot area and ensure national food security, the project owns very important theoretical and practical significance.

如何适应气候变化，时空耦合水土资源、挖掘粮食生产潜力，既是全球变化适应性研究的热点问题，也是当前农业水土工程、土地资源利用和水文地理亟待解决的关键问题之一。挠力河流域是典型的商品粮输出基地，上世纪90年代以来，在“气候-政策-人类活动”驱动下，耕地数量扩张及内部结构调整剧烈，出现一系列水土资源利用不协调问题，亟需通过耕地调整以达到水土资源平衡利用状态。本项目围绕气候变化下水土资源平衡综合应对的重大实践需求，以自然-人工-政策三元水土资源耦合为主线，遵循“过程-机制-影响-调控”的研究思路，以多学科理论方法为依据，划分耕地类型为旱地、水浇地、井灌水田和渠灌水田，提取和分析挠力河流域水田化进程情况，基于系统理论分析耕地演化驱动机制；构建基于流域的自然-人工-政策三元水土资源平衡理论系统，并研究整体驱动模式；从农田水分平衡、水资源利用下土地资源响应和造成的外部影响效应三方面进行系统的水土资源平衡效应分析，实现耕地调整，并提出最终的水土资源适应性对策。本项目将对于深化气候变暖背景下水土资源平衡效应研究，推动现代农业综合配套改革试验区建设和保障国家粮食安全，具有重要的理论和实践意义。

围绕气候变化下水土资源平衡综合应对的重大实践需求，以水-土资源系统耦合为主线，遵循“过程-机制-影响-调控”的研究思路，以多学科理论方法为依据。提取和分析上世纪90年代以来挠力河流域耕地利用变化信息，研究水土资源平衡理论，并分析其平衡效应机理，评估该流域耕地利用下水土资源平衡效应，进行未来影响因素和水分供需状况的模拟分析。研究认为，该流域水田化过程极其强烈，已进入水田化中期阶段，水田整体偏移特征恰与三江平原水田“北移东扩”的整体特征相反；降水特征差异较三江平原其他地区更为突出，夏季降雨量逐渐下降，水分供应条件逐渐变差；径流分布差异较大，南部和东南部地区径流量偏低，干流沿岸和内外七星河地区地表径流量偏高；流域常年处于“负”的气候水分盈亏态势，旱地和水田的气候水分盈亏绝对值逐年下降，初始层次水分亏缺态势向良性发展；不同作物水分盈亏特征差异较大，缺水是该流域土壤水分平衡的最主要特征，同时不同年际间表现出较为明显的差异特征，缺水的高值区多位于挠力河干流沿岸地区和内外七星河腹地，该地区为挠力河流域水田化扩张的核心区域，耕地高水分亏缺地区的面积也迅速增加，高水分亏缺地区更为集中，且分布范围更广。为保障挠力河流域的水土资源综合利用，应从科学调整作物结构布局、实施农田精准灌溉管理、实施区域间的调水工程和合理开采地下水4个方面来开展。本项目对开展现代农业试验区农业结构调整和建设高标准农田具有重要的理论和实际指导意义。