基于DSSAT模型的晋南小麦节水灌溉应用

Application of the DSSAT Model in Wheat Water-saving Irrigation Management in the Southern Shanxi

作物模型是一种机理性模型,综合考虑了与作物生长相关的环境和栽培技术,能合理地模拟作物在整个生育期的生理过程。引入DSSAT模型研究晋南麦区小麦生长过程,验证和评估DSSAT模型的适用性,通过DSSAT模型灌溉情况假设,分析该地区的节水灌溉制度。结果表明,小麦生育期的模拟误差均在3 d以内,小麦模拟产量的归一化均方根误差(RRMSE)均小于10%,D指数(D-index)均大于0.95,残差系数(CRM)均接近于0,表现出很好的模拟精度;在节水灌溉方面,在连续2 a的冬小麦生育期间,灌一次拔节水比雨养小麦增产3500 kg/hm2左右,灌2次水(越冬水+拔节水,拔节水+灌浆水)比灌1次水(拔节水)增产2000 kg/hm2左右,灌3次水产量增加并不十分明显。因此,DSSAT模型在晋南麦区具有较好的适应性,能为合理灌溉提供一定的支撑,为农业生产及节水灌溉提供一定的实践指导。

The Decision Support System for Agrotechnology Transfer(DSSAT)has been widely used because it can reasonably simulate the physiological process of crops throughout the growth period.In this paper,the DSSAT model was used to study the wheat growth process in the southern Shanxi and the adaptability of DSSAT model was validated and evaluated.By setting up a series of irrigation scenarios,the water-saving irrigation scheme was analyzed based on DSSAT model.The results showed that the simulation absolute errors of wheat growth period were both within 3 d,the normalized root mean square errors(RRMSE)of wheat simulated yield were less than 10%,D indexes were greater than 0.95,and coefficients of residual mass(CRM)were close to 0,which proved a good simulation performance.In the aspect of water-saving irrigation,it showed that in a normal rainfall year,irrigation should be selected at jointing stage in the case of only one-time irrigation in the wheat growth period and grain yield increased by about 3500 kg/hm2,compared with that in rain-fed condition.In the condition of two irrigations in the wheat growth period,if it had good moisture at planting time,jointing and grain-filling irrigation water were chosen,oppositely winter dormancy and jointing irrigation water were chosen and grain yield increased by about 2000 kg/hm2,compared with that with one-time irrigation.More irrigation did not have much positive effect on grain yield.In conclusion,the DSSAT model has a good adaptability in the local wheat area,and can provide some theoretical support for water-saving irrigation and practical guidance for local agricultural production.