根区局部灌溉和氮、钾水平对玉米干物质积累和水肥利用的影响

在玉米某一生育阶段实施根区局部灌溉，探索其水肥供应模式。通过盆栽试验，研究了在不同氮（N）、钾（K）水平下，苗期拔节期和苗期抽雄期分根区交替灌溉和固定部分根区灌溉对玉米干物质积累、水分利用和N、K吸收的影响。结果表明，与常规灌溉相比，苗期拔节期根区局部灌溉总干物质质量降低不明显或略有增加，而水分利用效率明显增加，且不影响玉米对N、K吸收量; 而苗期抽雄期根区局部灌溉虽降低耗水量31.0%38.4%，但明显降低玉米总干物质质量和N、K吸收量。相同灌溉方式下，中等 N、K水平（N和K2O均为 0.12 g/kg）处理的总干物质质量、地上部和总N、K吸收量比低N、K水平（N和K2O均为0.08 g/kg）的明显增加; 而高N、K水平（N和K2O 均为0.16 g/kg）与中等N、K水平无明显差异。说明适宜N、K水平时在玉米苗期拔节期进行根区局部灌溉效果较好。

Effects of partial root-zone irrigation and N,K levels on dry mass accumulation, water and nutrients use of maize

Partial root-zone irrigation (PRI) at a given growth stage was carried out to study water and fertilizer supply modes of maize. Under different N and K levels, effects of alternate PRI and fixed PRI on dry mass accumulation, water use and N, K uptake of maize during the seedling to jointing and seedling to tasselling stages were studied using the pot experiment. The results show that compared to the conventional irrigation, the total dry masses of maize under the PRI from the seedling to jointing stages are not increased or decreased significantly, while the water use efficiencies are increased without affecting N and K uptakes of maize. However, the total dry mass and N and K uptakes are significantly reduced under the PRI from the seedling to tasselling stages, although the water consumptions are reduced by 31.0%-38.4%. Under the same irrigation, the total dry mass, shoot and total N and K uptakes under the medium N and K levels (N and K₂O 0.12 g/kg, respectively) are more significantly increased than those of the low N and K levels (N and K₂O 0.08 g/kg, respectively), while those of the high N and K levels (N and K₂O 0.16 g/kg, respectively) are not more significantly increased than those of the medium N and K levels. Therefore, the partial root-zone irrigation from the seedling to jointing stages of maize is an efficient irrigation method under the medium N and K levels.