华北平原小麦－玉米两熟制节水潜力与灌溉对策

利用详细校正的农业系统模型可以综合土壤、气候及作物等因素综合评价节水灌溉制度，为农田水分优化调控提供理论和技术支持。该文利用根系水质模型（RZWQM-CERES）模拟分析了华北平原2个代表性站点（禹城和栾城）小麦-玉米两熟制下作物产量、农田蒸散和灌溉需水量多年的变化特征（1961－1999），结果表明栾城站小麦季农田最大蒸散量与灌溉需水量多年平均分别为632和496 mm，明显高于禹城站，而玉米季最大蒸散量相近，分别为395和384 mm。2个站点灌溉需水量都集中在小麦季（3－5月），但在栾城站播种期（6、10月）灌溉需水量较高。由于2站点气候和土壤条件的差异，作物产量对水分胁迫的响应特征明显不同，在获得相似目标产量时，禹城站灌溉需水量低于栾城站。以作物水分胁迫指数为基础的节水灌溉制度模拟评价表明2个站点冬小麦水分敏感期为孕穗期，但播前灌溉的产量效应差异明显。综合以上结果初步建立了2个站点高效用水和环境友好型的节水灌溉策略。

Water-saving potential and irrigation strategies for wheat-maize double cropping system in the North China Plain

Agricultural system models can be used to assess water-saving potential and irrigation strategies by integrating factors of soil, climate and crops, so as to provide theoretical and technical support for soil moisture optimal control.. In this study, RZWQM-CERES was used to simulate crop yield, evapotranspiration and irrigation requirement with various soil water levels and irrigation schedules in a wheat-maize double cropping system from 1961 to 1999 at Yucheng and Luancheng Stations. The results showed that the long-term averaged maximum evpotranspiration and irrigation requirement in wheat season were 632 and 496 mm at Luancheng, which were higher than that at Yucheng. The maximum evapotranspiration values in maize season were similar, which were 395 and 384 mm, respectively. For both two sites, high irrigation requirement concentrated in wheat season from March to May. At Luancheng, however, higher irrigation requirement occurred in June and October. Crop yield response to water stress differed greatly, where lower irrigation was required at Yucheng than at Luancheng for similar objected yield levels becaused of different climate and soil conditions between the two sites. The long-term irrigation schemes simulations showed that booting stage was the most sensitive growth stage of wheat to water stress at the two sites, but the pre-season irrigation showed great different effects on crop yield between the two sites. Based on above results, water-saving irrigation strategies with high water use efficiency and environmental benefits were established for the two sites.