Nutrient Management and Balanced Fertilization on Major Crops in Jilin Province

A field experiment at Gongzhuling determined the yield response equations for the corn variety Pioneer 335 to help optimize N, P, and K rates. Optimum rates for maximum profit were calculated to be 147 kg N, 65 kg P₂O₅, and 85 kg K₂O/ha. Optimal rates for a maximum yield were 160 kg N, 78 kg P₂O₅, and 91 kg K₂O/ha. The corresponding agronomic efficiency was 19.7-11.7-22.4 kg/kg N-P₂O₅-K₂O under maximum profit and 18.1-10.1-21.0 kg/kg N-P₂O₅-K₂O under maximum yield. Similar field trials on the soybean variety Jiyu 74 determined 76 kg K₂O/ha and 84 kg K₂O/ha, and for super rice 64 kg K₂O/ha and 71 kg K₂O/ha, as the optimal K application rates for maximum profit and maximum yield, respectively. The corresponding agronomic efficiency for soybean was 4.3 kg/kg and 4.0 kg/kg, and 8.5 kg/kg and 7.7 kg/kg for rice under K rates required for maximum profit and maximum yield, respectively.

Seven corn cultivars were planted based on the treatment of 180-75-75 N-P₂O₅-K₂O/ha and a unfertilized CK. Yields with fertilization ranged between 4.9 and 10.3 t/ha, and yield increased by 11 to 94% over those without fertilization. Thus, the response to fertilizer varied greatly across different cultivars. Xianfeng32D22, Xianyu 335, and Sidan 136 were classified as those with high response to fertilizer application with 32 to 94% higher yields compared to the unfertilized CK. Jidan 88 and Jidan 535 were classified as having a low response to fertilizer application with only 11 to 13% yield increases compared to the CK. Jidan 271 and Jidan 275 were classified as having medium response to fertilization due to 22 and 25% yield increases over the CK. Knowledge of cultivar response to fertilization is very important when considering the most appropriate fertilizer application rate. Jilin-NMBF