Abstract:

【Objective】 The study was conducted to reveal the difference and dynamic of grain yield in China under long-term fertilization, and to provide scientific references for evaluating and establishing long-term fertilization mode. 【Method】 Grain yield trends of rice, wheat and maize crops in different treatments (unfertilized control, fertilizer NPK, and fertilizer NPK plus manure, i.e., NPKM) under long-term fertilization were investigated and 700 sets of data were included. 【Result】 It was discovered that grain yield of unfertilized maize and wheat showed a very significant (P＜0.01) declining trend, the decline rates (per year) were -110.9 kg?hm-2 and -33.4 kg?hm-2, respectively, while rice yield was stable. Yield trends of the all three crops in NPK treatment decreased significantly (P＜0.05) with year, the yield decline rates of maize, wheat and rice were -90.9 kg?hm-2, -48.5 kg?hm-2 and -25.3 kg?hm-2, respectively. Grain yields of 3 crops were stable under NPKM fertilization. The coefficients of variation (CV%) of maize, wheat and rice decreased by 8%, 4% and 3% in NPKM treatment, respectively, compared with those of NPK treatment. The yields of wheat and maize varied greatly with year, while that of rice was stable relatively. A significantly positive correlation between the fertilized and unfertilized crop yields was found. When the yields of unfertilized crops increased by one unit, the magnitude of yields increased in NPKM treatments decreased by 0.12-0.31 kg?hm-2?a-1 compared with those in NPK treatments. The crop yields under long-term NPK fertilization was more dependent on soil basic fertility than that of NPKM fertilization. 【Conclusion】 The yield declining trends were observed in wheat and maize crops with no fertilizer or chemical fertilizers alone, while that of rice was relatively stable. Chemical fertilizer in combination with manure is a more effective fertilization to improve and maintain the grain yield, and it is strongly recommended for sustainable agriculture.

Key words: long-term fertilization')">long-term fertilization, wheat, maize, rice, grain yield trend