增施有机肥对稻田亚耕层土壤的培肥效应

通过大田试验，研究在施用化肥的基础上增施有机肥对耕层（0~15 cm）和亚耕层（15~30 cm）土壤养分含量及水稻产量的影响。结果表明，与单施化肥相比，增施牛粪和饼肥明显提升了土壤有机质、全氮和有效磷含量：在0~15 cm土层，增幅分别为32.17%和10.96%、30.69%和6.56%、131.48%和31.74%；在15~30 cm土层，增幅分别为10.72%和4.77%、6.72%和3.64%、62.69%和11.40%。增施有机肥后水稻产量增加、年度间稳定性提升，其中增施牛粪后产量增加7.98%，变异系数降低3.90个百分点，增施饼肥后产量增加7.72%，变异系数降低3.20个百分点。水稻产量和土壤各养分指标均存在一定程度的正相关，其中在亚耕层产量与有机质、全氮、有效磷的相关系数均高于耕层。耕层和亚耕层土壤有机质、全氮和有效磷含量极显著（P<0.01）影响水稻产量的稳定性。综上，增施有机肥在提高耕层和亚耕层土壤养分含量、水稻产量及其稳定性上均有较好效果，耕层和亚耕层土壤养分状况对水稻产量及其稳定性均有显著影响，生产上要重视对亚耕层土壤的培肥。

Effects of increasing application of organic fertilizer on subsoil fertility betterment in paddy field

Field trials were conducted to study the effect of soil nutrient contents in topsoil(0~15 cm) and subsoil(15~30 cm) and rice yield on the basis of the application of chemical fertilizer adding organic fertilizer. The results showed that the increasing application of cattle manure and cake fertilizer obviously improved the contents of organic matter, total nitrogen and available phosphorus in soil, with increase by 32.17% and 10.96%, 30.69% and 6.56%, 131.48% and 31.74% in topsoil, while improved by 10.72% and 4.77%, 6.72% and 3.64%, 62.69% and 11.40% in subsoil, respectively compared with the single fertilizer treatment. The treaments of increasing application of organic fertilizers increased rice yield and inter-annual stability. The yield of the increasing application of cattle manure and cake fertilizer treatments increased by 7.98% and 7.72%, while the coefficient of variation decreased by 3.90% and 3.20%. There were positive correlations of a certain extent between the rice yield and the soil nutrient indexes. The correlation coefficients of the yield with soil organic matter, total nitrogen and available phosphorus in subsoil was higher than those in topsoil. The contents of soil organic matter, total nitrogen and available phosphorus presented extremely significant(P<0.01) correlations with rice yield stability in topsoil and subsoil. In summary, increasing application of organic fertilizer had good effects on soil nutrient contents, rice yield and its stability. The emphasis of fertility betterment should be put on subsoil in production because the nutrient contents in topsoil and subsoil both could present an appreciable effect on rice yield and its stability.