华北平原不同种植模式作物耗水监测与特点分析

为探究华北平原不同种植模式的作物耗水与生产能力以评价其缓解地下水超采的潜力，于2021—2022年在中国农业科学院北京市顺义试验站进行了冬小麦-夏玉米、冬小麦-夏大豆和冬小麦-夏休闲3种种植模式的对比试验。利用大型称重式蒸渗仪监测各种植模式的蒸散、土壤储水和渗漏，使用FAO-56推荐的双作物系数法估算不同种植模式的蒸散量，同时分析了估算效果和蒸散与环境的响应特征，并比较不同种植模式的水分利用效率和产量、效益的相对关系。结果表明：3种种植模式的实测蒸散量与净辐射呈指数函数关系、与气温呈二次函数关系、与水汽压差呈线性函数关系，可以使用双作物系数法或非线性拟合公式较好地估算不同种植模式的蒸散量；冬小麦-夏玉米种植模式的产量、水分利用效率和经济效益最高，耗水量也最高，地下水净消耗量为197.52 mm，而冬小麦-夏休闲模式净地下水消耗量最小，比冬小麦-夏玉米模式低72.28%。未来需要结合华北平原不同区域可利用和开采的地表水、地下水资源量和土壤储水能力以及作物耗水量优化作物种植模式，以达到地下水的采补平衡。

Characteristics and monitoring of water consumption of various cropping systems in North China Plain

In order to explore the water consumption and productivities of various cropping systems to judge the potential of North China Plain in terms of alleviating the groundwater overexploitation, a comparative experiment of the water consumption and productivity of three cropping systems (winter wheat-summer maize system, winter wheat-summer soybean system and winter wheat-summer fallow system) was carried out at Shunyi Experimental Station of Chinese Academy of Agricultural Sciences from 2021 to 2022. A large-scale weighing lysimeter was used to measure the evapotranspiration, soil water storage and leakage and the dual crop coefficient method recommended by FAO-56 was used to estimate the evapotranspiration of different cropping systems. The estimation effect and the response characteristics of evapotranspiration to the environment were analyzed and the relationship between water use efficiency (WUE), yield and benefit of different cropping systems were compared. The results showed that evapotranspiration had an exponential relationship with net radiation, a parabolic relationship with temperature and a linear relationship with vapor pressure deficit, indicating that the FAO-56 dual crop coefficient method and nonlinear fitting formula could be used to estimate the evapotranspiration of the three cropping systems precisely. The winter wheat-summer maize system consumed the highest water with the groundwater consumption of 197.52 mm, though it achieved the highest yield, WUE and EWUE, whereas the groundwater consumption of the winter wheat-summer fallow system was 72.28% lower than that in the winter wheat-summer maize system. In the future, it is necessary to consider the availability of surface water and groundwater, as well as the soil water storage capacity when selecting the optimal cropping systems in different regions of the North China Plain, so as to improve crop management methods to achieve the balance of groundwater exploitation and replenishment.