Nutrient management and optimized fertilization on selected crops in Liaoning province

Experiments of nutrient management and balanced fertilization in Liaoning were carried out on rice, corn, and vegetables in 2007.

In rice, the balanced “optimum” (OPT) of 210-90-135 kg N-P₂O₅-K₂O/ha produced the highest yield of 8.7 t/ha. Treatments omitting N, P, and K produced 40%, 8%, and 24% less yield, respectively. The zero fertilizer check (CK) and the farmer practice (FP) of applying 210-105-105 kg/ha had 31% and 13% lower yields, respectively. The apparent recovery efficiency of N, P, and K was 43%, 6%, and 58%. One kg N, P₂O₅, and K₂O produced 16.3 kg, 7.8 kg and 15.3 kg yield, respectively. At this site, N was the most significant nutrient limitation.

Nutrient omission treatments within a corn field trial at Xinmin determined that yields would decline from 8.2 t/ha, produced with the OPT of 180-30-135 kg/ha, to 7.6 t/ha (-8%), 7.8 t/ha (-5%), and 6.9 t/ha (-16%) under -N, -P, and -K treatments. The CK produced 18% less yields while FP of applying 180-90-90 kg/ha produced 5% less yield. The apparent recovery efficiency of N, P, and K was 8%, 24%, and 42%. Agronomic efficiency of N, P, and K was 3.4 kg/kg, 14.6 kg/kg, and 9.7 kg/kg. A fixed-site field trial found 10%, 15%, 16%, and 21% corn yield increases with 45, 90, 135, 180 kg K₂O/ha compared to the 6.6 t/ha that was obtained under a zero K CK using 180-30-0 kg/ha.

A 15-year, fixed-site experiment on corn conducted in Shenyang continues to produce significant responses to K application. Yield increased by 7% and 8% due to 112 and 225 kg K₂O/ha, compared to 8.8 t/ha obtained in the zero K CK using 300-150-0 kg/ha. These yield increases translate into higher net returns of US$57/ha and US$19/ha, respectively. One kg K₂O produced 5.5 kg and 3.2 kg corn yield under 112 and 225 kg K₂O/ha, respectively. In the 0 to 20 cm and 20 to 40 cm soil profile, the content of slowly released K, available K, and the total K increased with K application.

In tomato, yield increased by 13%, 13%, 15%, and 19% due to 100, 200, 300, and 400 kg K₂O/ha application, compared to 97 t/ha obtained in the zero K check with 350-180-0 kg/ha. Vitamin C content increased by 3.4 to 7.3 g/100 g and total soluble sugar content increased by 0.1 to 0.5% with K application. In cucumber, yield increased by 3%, 4%, 16%, and 6% due to 100, 200, 300, and 400 kg K₂O/ha application, compared to 63 t/ha obtained in the zero K check with 400-200-0 kg/ha. Liaoning-NMBF