关键词: 小麦, 产量, 氮肥, 磷肥, 钾肥, 化肥减施, 减肥潜力

Abstract:

【Objective】It is of great significance to understand problems in farmers’ fertilizer application and the potential to reduce the fertilizer rates, with the purpose to realize scientific fertilizer recommendation and reasonable reduction of fertilizer input in major wheat production regions of China. 【Method】A three-year long in-farm fertilization survey and collection of soil and plant samples were carried out to analyze and evaluate the fertilization status and fertilizer reduction potentials based on the wheat yield levels, nutrient requirement and soil nutrient supply capacities in major wheat production regions of China. 【Result】The average wheat grain yields were significantly and linearly correlated with their biomass, with the average to be 6.0 and 13.2 t·hm ^-2 for farmers over all the major wheat regions in China, respectively. However, the yields showed no significant correlation with the fertilizer application rates and soil nutrients, and the average application rates for nitrogen (N), phosphorus (P₂O₅) and potassium (K₂O) were 191.1, 112.8 and 53.4 kg·hm ^-2, respectively. In the spring wheat region, the averages were correspondingly 171.7, 108.9 and 10.6 kg·hm ^-2, 154.3, 111.8 and 32.6 kg·hm ^-2 in dryland wheat region, 236.4, 128.1 and 74.0 kg·hm ^-2 in wheat-maize region, and 177.5, 77.0 and 71.8 kg·hm ^-2 in rice-wheat region, respectively. For the N, there were less farmers, only 34% over applied fertilizers in the spring wheat region, and then it was 42% in wheat-maize region, 55% in rice-wheat region, and 63% in dryland wheat region, with the low-yielding farmers to be the focus of N fertilizer reduction, the reduction potential to be 43.6%, and the average N reduction of 2.3-135.5 kg·hm ^-2. The problems for over P fertilizer application were more obvious, with 63%, 87%, 68% and 57% of farmers to apply excessive P fertilizer respectively in the four regions. Even at the high-yielding levels, there were still more than 50% of farmers apply excessive P fertilizer, and all the farmers need to reduce their P fertilizer, with the average reduction to be 3.8-91.1 kg P₂O₅ ·hm ^-2, and dryland wheat region of the largest reduction potential, which was 55.6% of their current P rates. Situation for K application was variable with regions. In spring wheat region, 84% of famers applied insufficient K fertilizers, with an average of 22.8 kg·hm ^-2 extra K₂O needed to be applied. While, in dryland wheat, wheat maize and rice wheat regions, 43.2%, 25.7% and 56.0% of their current K fertilizer application should be reduced, with the low yielding farmers to be the key in K fertilizer reduction and the average reduction of 31.7-45.9 kg K₂O·hm ^-2. 【Conclusion】Fertilizer application and its reduction potential were found to vary with the yields and regions for wheat farmers in China. Situation of excessive fertilization was more serious for low- and medium-yielding farmers. Application of N and K fertilizers should be reduced according to the wheat yield levels, and all farmers should pay special attention to their over P fertilizer application, and reduce the P application rates to reasonable levels. Fertilizer reduction potential was the highest in the dryland wheat region for N and P fertilizers, and in rice wheat region for K fertilizer.

Key words: wheat, yield, nitrogen fertilizer, phosphate fertilizer, potassium fertilizer, fertilizer reduction, fertilizer reduction potential