Nutrient Management and Optimized Fertilization on Wheat and Maize in Hebei Province

Hebei is a grain production base for winter wheat and summer maize. Research activities in 2008 focused on optimizing nutrient management in these crops. Nutrient omission treatments were examined within a winter wheat-summer maize rotation system in a medium fertility soil in Xinji County. A separate trial also examined the extent to which N, P, and K rates could be adjusted on summer maize.

The highest yields in the nutrient omission trial were achieved with the balanced optimum (OPT) of 180-75-120 kg N-P₂O₅-K₂O/ha in wheat (6.9 t/ha) and 210-75-120 in maize (8.7 t/ha). Yields were 9%, 0.4%, and 0.4% lower without N, P, and K in wheat, and 17%, 5%, and 6% lower without N, P, and K in maize. Agronomic efficiency of N within the OPT was 3.6 kg grain/kg and 7.1 kg/kg for wheat and maize, respectively. The minimal yield loss with the deletion of P and K in this trial, and the very low agronomic efficiency recorded, indicate that soil test recommendations do not accurately represent the soil nutrient status at this location.

In the rate trial, a highest maize yield of 9.1 t/ha was achieved with 210 kg N/ha, but differences in yield were not significant between N rates ranging between 70 to 350 kg N/ha. Adjustments in P rate resulted in a highest yield with 135 kg P₂O₅/ha, but again no yield differences existed between 45 to 180 kg P₂O₅/ha. Similar results were obtained with K as no yield differences existed among K rates between 45 to 360 kg K₂O/ha. This study demonstrates that new strategies are required regarding fertilizer use and efficiency in medium or high fertility soils in the Hebei plains. Hebei-NMBF