控制性分根区灌溉对玉米根区水氮迁移和利用的影响

Effects of controlled root-divided irrigation on transport and utilization of water and nitrogen in maize rootzone soil

为探索灌水方式对根区水氮迁移和利用的影响,对盆栽玉米采用3种灌水方式(常规、交替、固定)和4个氮素水平,研究了不同根区湿润方式对玉米根区水氮迁移动态和利用的影响。结果表明:施氮后盆内土壤硝态氮含量和施氮量呈正相关,交替灌溉根区两侧土壤硝态氮分布均匀,固定灌溉根区干燥侧土壤硝态氮累积量明显大于湿润侧。交替灌溉上层土壤硝态氮残留量和常规灌溉同一层次上的残留量相当,下层的残留量比常规灌溉的大。交替灌溉的根冠比最大,固定灌溉的次之,常规灌溉的最小。交替灌溉的水分利用效率是常规灌溉的0.99～1.11倍,而灌水量是常规灌溉的0.75倍,节水效果明显。同一氮肥水平下,交替灌溉的单位干物质全氮吸收量最大,固定灌溉的次之,常规灌溉的最小。

The object of this study was to explore the effect of irrigation method on transport and utilization of water and nitrogen, the pot experiment was conducted about three irrigation methods （conventional irrigation, alternate partial rootzone irrigation, fixed partial root-zone irrigation） and four levels of nitrogen. The influence of different irrigation methods on dynamics and utilization of water and nitrogen in rootzone soil was studied. Results showed that soil NO3-N content was positively correlated with the amount of nitrogen application, soil NO3-N content on both sides of the rootzone of alternative irrigation was evenly distributed, and the soil NO3-N accumulation in dry side was significantly greater than that in wet side of fixed irrigation. The NO3-N residue in upper soil of alternative irrigation was approximately equal with that of conventional irrigation, while the residue in lower soil of alternative irrigation was much more than that of conventional irrigation. The root/shoot ratio of alternative irrigation was the biggest, followed by that of fixed irrigation, and that of conventional irrigation was the least. The water use efficiency of alternative irrigation was 0.99-1.11 times of the conventional irrigation, the irrigation amount of alternative irrigation was 0.75 times of the conventional irrigation, so water-saving effects of alternative irrigation were evident. At the same level of nitrogen fertilizer, nitrogen absorption of per dry mass of alternate irrigation was the largest, followed by that of fixed irrigation, and that of conventional irrigation was the least.