我国华北地区土壤水效用对玉米旱灾风险的影响机制研究

Based on disaster risk assessment, water cycle and crop model simulation, taking North China Plain as an example, a "Danyu thirteen" maize variety was selected, the hydrological and crop module of EPIC (Erosion-Productivity Impact Calculator) model were used to simulate the soil water cycle in farmland and growth processes of maize. Based on the concept of agricultural soil water utility, the evaluation index system and method of the effective use of soil moisture were constructed. Through crop simulation and quantitative evaluation of soil water utility, the spatial and temporal variation law of agricultural soil water utility was revealed under different irrigation scenarios, the response relationship of agricultural soil water utility levels on maize yield by drought was analyzed. Combined with management status in North China, the spatial and temporal control measures of regional soil moisture and preventive measures of maize drought risk were put forward. This research will provide new ideas for easing the contradiction between supply and demand of agricultural water use in the current strong human activities, to ensure national food safety, and the development of digital agriculture in China.

本研究基于灾害风险评估、农田水循环、作物模型等理论和技术，以我国农业供用水矛盾突出的华北平原为例，选取“丹玉十三”玉米品种，利用作物EPIC模型中的水文和作物模块分别对农田土壤水循环过程与玉米生长过程进行耦合模拟。在此基础上，构建基于土壤水分效用概念的土壤水有效利用评价指标体系和方法。通过模型模拟和土壤水效用的定量评价，揭示不同灌溉情景下农田土壤水效用的时空分异规律，定量分析农田土壤水效用程度对玉米旱灾产量的响应关系。结合华北地区农田耕作管理现状，提出区域土壤水全时空调控措施及玉米旱灾风险防范对策，为缓解当前强人类活动下农业用水的供需矛盾，保障国家粮食生产安全，发展数字农业提供新思路。

粮食安全问题是国际社会永恒关注的焦点。玉米不仅是高产的粮食作物，还是优良的饲料作物，更是多种工业的重要原料。玉米是中国最主要的粮食作物之一，因其较高的需水量，受气候影响，极易遭受旱灾。以华北地区为例，从风险的角度进行农业旱灾评价，对于农业旱灾预警和保障国家粮食安全具有重要的现实和指导意义。在全面收集研究区气象、土壤、土地利用、农气观测等资料的基础上，基于农业旱灾风险评价的概念框架“致灾因子危险性H评价—承灾体脆弱性曲线Vc 评价—作物减产风险性R评价(Risk)”，采用作物模型模拟和数字制图等技术，分别从全生育期和分生育期角度，对华北地区玉米旱灾风险的时空分布进行了定量评价。结果表明：在2、5、10 和20 年一遇致灾水平下，华北地区玉米旱灾减产风险总体呈现出从西北向东南方向递减的趋势，这主要由气候环境和下垫面的地形地貌条件所决定。20 年一遇水平时，产量损失风险的高值区(R ≥ 0.5) 集中分布在冀北高原山地和山东省中南部地区，占玉米总面积的7.63%。成灾风险较高的生育期：拔节期—抽雄期、抽雄期—乳熟期、乳熟期—成熟期应加强防范。研究可为高风险区和高风险时段的农业旱灾风险防范和适应性对策制定提供理论依据和科技支撑。