Evaluation of In-Season Nitrogen Management for Summer Maize in North Central China

الملخص EN

We conducted field experiments in which nitrogen (N) was applied to summer maize at different rates and different basal/topdressing ratios.

The experiments were carried out in 2009 in Hengshui and Xinji, Hebei province, China.

The results showed that basal application of N was necessary for maize growth in early summer and for high grain yields.

For the Hengshui and Xinji sites, 30 and 57 kg N ha−1, respectively, would meet the N demands of maize before 7-leaf stage.

The total rates of 120 and 180 kg N ha−1, respectively, would maximize grain yields, and in-season N management based on crop N demands and soil N supply could reduce N inputs by more than 50% in Hengshui and 25% in Xinji, respectively, in one maize growth season, compared with farmers' practice, but the sustainability of the optimum N rates for maximum grain yield of next seasons crop needs to be further studied.

Optimum N management should take into account the existing nutrient conditions at each site, soil fertility and texture, and crop demands.