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

Henan is one of the main production bases for wheat, corn, and vegetables in China. In 2006, five winter wheat field trials compared a complete treatment of 225-120-180 kg N-P₂O₅^-K₂O/ha, which was compared to PK, NK, NP combinations and a zero fertilizer check. Four summer corn field trials included an OPT treatment using 225-90-180 kg/ha, plus a PK, NK, and NP combinations. A K rate study on Chinese cabbage compared 0, 75, 150, 225, 300, and 375 kg K₂O/ha in combination with 300 kg N/ha and 225 kg P₂O₅/ha.

In wheat, the highest yields were achieved with the OPT treatment which produced 7.2 t/ha, 7.7 t/ha, 7.4 t/ha, 7.3 t/ha, and 7.1 t/ha in Yicheng, Suiping, Mengjin, Yanjin, and Nanyang counties, respectively. Yields were 22 to 36% lower without N, 11 to 14% lower without P, and 7 to 20% lower without K. The OPT treatment also produced the highest corn yields. The average yield across the four sites was 9.7 t/ha. Yields were 37 to 42% lower without N, 10 to 13% lower without P, and 18 to 24% lower without K. In Chinese cabbage, the highest yield of 18.6 t/ha was obtained with 300 kg K₂O/ha, and net income due to K application varied from US$415/ha to US$1,058/ha. Henan-NMBF