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

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.