秸秆还田配施腐熟剂对低产黄泥田的改良作用

Effect of returning straw added with straw-decomposing inoculants on soil melioration in low-yielding yellow clayey soil

【目的】低产黄泥田是一种发育程度低的水稻土,土壤贫瘠,作物产量低。本文研究探讨了小麦、水稻、油菜秸秆还田及配施秸秆腐熟剂后秸秆还田对低产黄泥田的土壤改良效果。【方法】在荆门市双季稻区设置了单施化肥(对照),化肥配施小麦、水稻、油菜秸秆,化肥配施小麦、水稻、油菜秸秆同时添加秸秆腐熟剂等七个处理的田间试验。取样分析了这些处理对双季稻产量、土壤理化性质、土壤团聚体组成、土壤腐殖质组成及结合形态的影响。【结果】1)在早、晚稻上秸秆还田配施秸秆腐熟剂增加了稻谷的产量,比单施化肥最多增产1423.2 kg/hm2,增幅为23.5%;添加秸秆腐熟剂也能够增加稻谷的产量,比单独秸秆还田最多增产653.8 kg/hm2,增幅为9.6%。与对照比较,油菜秸秆+腐熟剂处理晚稻显著增产。2)土壤有机质、全氮、碱解氮、有效磷、速效钾含量、阳离子交换量秸杆+腐熟剂处理高于对应的秸秆还田处理,而土壤容重则下降。3)与对照比较,秸秆处理>5 mm土壤风干团聚体含量增加3.78%8.62%,>0.25 mm土壤风干团聚体含量也都增加,<0.25 mm水稳定性团聚体含量下降。秸秆还田有利于>0.25 mm水稳定性大团聚体总量的增加,减少了土壤团聚体破坏率。4)与对照比较,秸秆处理的土壤水溶性物质、土壤胡敏酸、富里酸、可提取腐殖物质总量、胡敏素含量增加。添加腐熟剂后,胡敏酸与富里酸比值低于相对应的秸秆还田处理;土壤松结合态腐殖质、稳结合态腐殖质、紧结合态腐殖质含量及结合态腐殖质总含量都有所增加。结合态腐殖质中松结合态腐殖质含量最高,所有的处理都在60%以上。【结论】秸秆还田配施秸秆腐熟剂不仅能够增加早稻和晚稻的稻谷产量,还提高了土壤有机质、全氮、碱解氮、有效磷、速效钾含量及阳离子交换量,降低了土壤容重。秸秆还田主要提高了>0.25 mm风干团聚体、水稳性大团聚体含量,减少了土壤团聚体破坏率。秸秆还田处理显著提高了土壤松结合态腐殖质含量和结合态腐殖质总含量。秸秆还田配施秸秆腐熟剂可以提高作物产量、提高土壤肥力、改善土壤结构、增加土壤腐殖质含量与活性,能够改良低产黄泥田。化肥+油菜秸秆+秸杆腐熟剂处理是一种良好的低产黄泥田改良措施。

[ Objectives ] The yellow clayey soil is a less developed paddy soil. A field experiment was carried out to investigate the melioration effect of returning straw added with straw-decomposing inoeulants in low-yielding yellow clayey soil. [ Methods ] Three kinds of treatments were established ： single chemical fertilizer as control, chemical fertilizer ＋ returning wheat straw, rice straw or rape straw, and these straw returning ＋ straw-decomposing inoculants. Crop yields, soil physical-chemical properties, proportion variation of defacement sizes of soil aggregates, the composition and combining form of soil humus were investigated in double cropping rice in JingmenCity, Hubei Province. [Results] Both the early and late rice yields were increased with returning straw ＋ straw- decomposing inoculants, with the highest increase of 1423.2 kg/hm2, equaling to 23.5%. Compare with returning straw only, the rice grain yields with the returning straw ＋ straw-decomposing inoculants was increased by 653.8 kg/hm2, or by 9.6%. In comparison to control, late rice grain yields with rape straw returning ＋ straw- decomposing inoculants were significantly increased. The contents of soil organic matter, total N, alkali- hydrolysable N, available P, available K and the cation exchange capacity with treatment of returning straw ＋ straw-decomposing inoculants were higher than those with the treatment of returning single straw only, but the effect in soil bulk density was opposite. Compared to CK, the percentage of soil dry-aggregates 〉 5 mm with straw returning were increased by 3.78%-8.62%, those 〉 0. 25 mm were also increased, but those 〈 0.25 mm were decreased. In addition, the treatment of straw returning increased the content of water soluble substance, humic acid, fulvic acid, humin and extracted humic substances in soil. The ratio of humic acid versus fulvic acid in the straw returning treatments with addition of straw-decomposing inoculants were lower than in the treatments without addition. Compared with CK, the contents of loosely, firmly, tightly combined humus and the total combined humus in the straw returning treatments were all increased, and the contents of loosely combined humus are higher relative to those of firmly and tightly combined humus, and the percentage content was over 60%. [ Conclusion] Straw returning plus straw-decomposing inoculants is effective in rice yield increases and amelioration of the tested soil. Except the soil bulk density, all the tested items are enhanced more with the treatments of straw returning plus inoculants than with straw returning only. Therefore, the addition of straw-decomposing inoculants is recommended in the low yield clayey soils for the high efficiency of straw returning practice.