Yield response to NPK fertilization and the main impacts in production of winter wheat in Yangtze River catchments of China

Objectives This study analyzed the effects of N, P and K fertilizers on wheat yield in the Yangtze River catchments, and the contribution rates of the main influencing factors for the yield responses, which will provide data support for the managements of NPK fertilizers in production of wheat in the area.

Methods The data were obtained from both the wheat field trials conducted by the International Plant Nutrition Institute in the Yangtze River catchments of China, and the published papers by searching the key words including winter wheat, winter wheat + yield, winter wheat yield + fertilizer utilization, etc. in CNKI database. According to the requirement of Meta-analysis, there are total of 724, 624 and 658 data for nitrogen, phosphorus and potassium fertilization. The effect value of a nutrient was defined as the response ratio of its fertilization over no-fertilization treatment within a same trail, and Meta-analysis method was used to quantitatively analyze the contribution of each factors on the yield response effect.

Results The application of NPK fertilizers increased the wheat yield in Yangtze River catchments significantly, and the yield increase rates by N, P and K fertilizers were averaged 66.0%, 17.9% and 10.0%, with the highest positive effect by N fertilizer. The yield effect was significantly affected by the inherent soil productivity, and the yield increase rates were as high as 134.2%, 30.0% and 12.1% on the low-productivity soil (yield < 2.0 t/hm²). There was a negative correlation between the yield-increasing effect of nitrogen and phosphate fertilizers and the inherent soil productivity. The fertilization effect varied significantly among planting areas, the highest N effect was in Chongqing 136.1%, ln (R) = 0.859, highest P effect in Zhejiang Province 39.1%, ln (R) = 0.330, and the highest K effect in Guizhou Province 19.1%, ln (R) = 0.175. N, P and K fertilizers all had the best yield-increasing effects in acidic soils. The yield-increasing effects showed a downward trend with soil pH increasing, and the yield-increasing rates were 95.2%, 29.4% and 14.0%, respectively. Soil organic matter content had a significant effect on P production, but not on N and K. In soil of total-P > 1.0 g/kg, total-K > 20.0 g/kg, available-N < 80.0 mg/kg, available-P > 25.0 mg/kg and available-K < 90.0 mg/kg, N application had the most obvious yield increase. In soil of total-P < 0.7 g/kg and available-P < 15.0 mg/kg, P application was the most effective, and in soil of available-K < 90.0 mg/kg, K application increased the most.

Conclusions The yield of winter wheat could be increased by 66.0%, 17.9% and 10.0% through the application of nitrogen, phosphate and potash fertilizers in Yangtze River catchments, respectively, and nitrogen is still the most effective nutrient. The inherent soil productivity affects the nutrient efficiency significantly and the high nutrient efficiency will be in the plot of yield < 2.0 t/hm². The pH, organic matter and mineral nutrient content should be taken as the basis of fertilizer input in the winter wheat planting areas in Yangtze River catchments.