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

Wheat field trials testing N, P, and K rates in Yanjin determined 210-105-105 kg N-P₂O₅-K₂O/ha (OPT) to be the best balanced recommendation. This option produced 890 kg/ha (11%) more than the farm practice (FP) treatment of 195-75-75 kg/ha. Profits under the nutrient omission treatments were 150 to US$500/ha less than the OPT. The highest wheat yield at Yicheng County was 8.1 t/ha under a similar OPT treatment of 225-105-105 kg/ha.

Maize field trials in Zhumadian County found 210-90-90 kg/ha to be most appropriate, while in Yanjin the rates of 180-60-150 kg/ha obtained the best results. Profits under the nutrient omission treatments were US$130 to US$550/ha less than this OPT. At Yicheng, the highest maize yield was 8.7 t/ha under the OPT treatment.

Nitrogen timing trials also tested application options for winter wheat and maize in Yanjin. Using a standard rate of 225 kg N/ha, compared to no N application, grain yield increased by 15%, 26%, and 48% with, respectively, (1) basal N only, (2) 1/2 basal and 1/2 topdressed at re-greening stage, and (3) equal splits between pre-sowing, re-greening, and jointing stages. For summer maize, 195 kg N/ha was applied on the preceding winter wheat plots. Compared to no N applied, maize grain yield increased by 31%, 43%, and 57% under, respectively, (1) topdressing at the seedling stage, (2) 1/2 at seedling and 1/2 at jointing, and (3) equal splits between seedling, jointing, and tasselling. Large yield (and efficiency) advantages are suggested with N application schemes which put less emphasis on one-time pre-sowing application practices for both wheat and maize in Yanjin. Henan-NMBF