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.