根据水量循环平衡原理,引用北京市旱情监测资料,建立了增、退墒经验模型,以此编制了不同土壤类型、不同作物和不同季节的墒情预报。 According to the principle of water cycle balance, the data of drought monitoring in Beijing were used to establish the experiencing model of increasing and returning moisture, and the soil moisture of different soil types, different crops and different seasons were prepared.