华北高产粮区基于种植制度调整和水氮优化的节水效应

Water-saving effect under adjustment of cropping systems and optimization of water and nitrogen in high yield regions of North China

冬小麦/夏玉米一年两熟是华北平原粮食作物主要的种植方式。冬小麦生育期降水少,春季灌溉是保证其高产的必要措施。基于上述问题,在华北平原高产粮区设置田间试验,研究了调整种植制度和水氮优化等措施下的节水效应。结果表明,将一年两熟的冬小麦套种夏玉米调整为冬小麦直播夏玉米,并结合水氮优化等措施,能降低作物耗水15%,提高灌溉水利用效率52%～54%,而产量并没有下降;而将一年两熟调整为两年三熟和一年一熟,尽管能降低作物耗水24%～31%,且能提高灌溉水利用效率58%～172%,但产量却下降16%～27%。综上所述,该区将现行的一年两熟制中的套种调整为直播,并加以水氮优化等措施,是目前较为适宜的种植方式。考虑到该区水资源严重短缺的现实,两年三熟制可能是未来的种植趋势,但需要挖掘其产量潜力。

Winter wheat-summer maize double cropping is an important rotation system mainly practiced in the North China Plain. Crop yield and water use efficiency in this rotation system are influenced by rainfalls. Winter wheat yield was restricted by limited precipitation and irrigation in spring. To study water-saving rotation system and measures, a 2-year field experiment was conducted in the high yield regions of the North China Plain by adjusting cropping systems and optimizing water and nitrogen management strategies. Six rotation cropping systems, including convention （Con）, optimum （Opt）, No-Tillage （No-T）, water saving I （WS I）, water saving II （WS II） and water restoration （WR）, were designed to investigate the crop yield, crop water consumption and irrigation water-use efficiency. The Con treatment as CK was a double cropping system of winter wheat interplanted with summer maize, which was conducted with conventional agricultural practice. Both Opt and No-T treatments were the double cropping system of winter wheat rotated with summer maize, and conducted with water and nitrogen optimization measures. WS I and WS II treatments were the three-crops in two years system, and combined with water and nitrogen optimization measures. The former was winter wheat-summer maize-spring maize rotation and the latter was winter wheat-summer soybean-spring maize rotation. The WR treatment was one crop （spring maize） in a year system and was also conducted with water and nitrogen optimization measures. Compared with the double cropping system of winter wheat interplanted with summer maize, the system of winter wheat rotated with summer maize by water and nitrogen optimization, the results presented a high level of production and low level of crop water consumption with the irrigation water-use efficiency improved by 52%-54%. Compared with the double cropping system, either the three crops in two years system or the one crop in a year system, significantly decreased crop water consumption, improved the irrigation water-use efficiency by 58%-172% and decreased the production by 16%-27%. In conclusion, it is feasible to change the winter wheat / summer maize double cropping system into winter wheat rotated with summer maize system under water and nitrogen optimization strategies in the North China Plain. Considering the fact of severe water shortages in this region, the three-crops in two years system may be a useful mode of planting to obtain the highest possible crop yield.