长期单施有机肥和化肥对土壤养分和小麦产量的影响

【目的】等氮、磷、钾养分投入条件下，探索黄淮海小麦主产区化肥和有机肥施用对小麦的增产效果以及土壤养分的演变规律，为小麦科学施肥及土壤肥力的提升提供依据。【方法】本研究以8年长期定位试验为平台，在冬小麦—夏玉米的传统种植制度下，有机肥和化肥处理均分别设置5个施氮 (N) 量:0、120、240、360、600 kg/hm2，共9个处理。化肥处理的磷、钾用量等同各有机肥处理带入的量。于每年小麦收获期测定小麦产量和土壤养分含量。【结果】在土壤养分方面，土壤有机质、全氮、有效磷、速效钾含量均随有机肥用量的增加而增加，并且呈逐年增长的趋势。化肥在提高土壤有机质及全氮方面与施肥量无明显关系，年际间差异不明显，基本处于同一水平。增施化肥在开始几年能够缓慢提高土壤有效磷和速效钾的养分含量，之后保持稳定。在同一施氮水平下，有机肥处理土壤有机质、全氮、有效磷钾养分含量均显著高于化肥各处理。在作物增产方面，施氮240、360、600 kg/hm2的有机肥处理小麦产量均显著高于施氮120 kg/hm2的有机肥处理，但三个处理之间差异不显著；化肥各处理间均差异不显著。除施N 120 kg/hm2水平下，化肥处理产量显著高于有机肥处理外，其他相同氮水平下化肥处理与有机肥处理无显著差异。【结论】有机肥在培肥土壤方面，效果明显优于化肥，并且有机肥处理随施肥量的增加能够持续提高土壤养分库容量，而化肥对于土壤养分的提升效果不大，始终处于一个相对较为稳定的水平。有机肥和化肥施用均对小麦产量具有显著的提升效果。在N 120 kg/hm2的低氮条件下，化肥对小麦的增产效果优于有机肥，而在高于N 240 kg/hm2的养分条件下，有机肥与化肥增产效果基本一致。另外，当产量提高到一定水平后，增加施肥量无助于作物产量的提高。

Effects of organic fertilizer and inorganic fertilizer on the wheat yields and soil nutrients under long-term fertilization

【Objectives】The effects of chemical fertilizer and organic fertilizer on the wheat yields and soil nutrients under the condition of equal NPK nutrient input, were investigated to determine the optimum application amount of each fertilizer. This result could provide a basis for the scientific fertilization of wheat and the improvement of soil fertility.【Method】The experiment was started in 2006 with organic manure and chemical fertilizer applied with five nitrogen rates (0, 120, 240, 360, 600 kg/hm2), respectively. Therefore, there were nine fertilization treatments in total. During the eight-year field experiment, the crop yields and soil nutrients were measured after wheat harvested.【Results】The contents of soil organic matter, total N, available P and readily available K increased with organic fertilizer application increment and application years. For chemical fertilizer, the contents of organic matter, total N, available P and readily available K increased slowly, and there was no significant difference among treatments and among cultivation years. In the first few years, the increase of chemical fertilizer input could slowly increase the content of the soil available P and readily available K, and then they remained at a stable level. Under the same N level, the nutrient content of soil treated with organic fertilizer was significantly higher than that treated with chemical fertilizer. In treatments of organic fertilizers, the treatments of N 240, 360, and 600 kg/hm2 obtained significantly higher wheat yields than N 120 kg/hm2 treatment did, and no significant difference was observed among the three treatments. In treatments of inorganic fertilizers, there was no significant difference in yields among them. Under equal N application rate, no significant difference was observed between the organic and inorganic fertilizer treatments, except for N rate of 120 kg/hm2, in which the wheat yield in inorganic treatment was significantly higher than that in organic one.【Conclusions】Soil nutrients show increase trend with the increase of organic fertilizer input, while they stay stable with the increase of inorganic fertilizer input. Organic fertilizer performs better than inorganic fertilizer in increasing soil nutrient levels. Both organic and chemical fertilizers have significantly increased wheat yield. When the N input level is less than 120 kg/hm2, inorganic fertilizer could obtain higher yield, when the N input levels are higher than 240 kg/hm2, inorganic and organic fertilizer have similar yields, and wheat yield would not increase when excess N is applied.