秸秆粉碎氨化还田对土壤体积质量及持水特性的影响

为尝试解决秸秆还田中秸秆分解缓慢、易诱发病虫害及与作物争氮等问题，通过室内土柱培养试验对比研究了秸秆粉碎程度及秸秆不同C/N值对自身分解速率、土壤体积质量、土壤持水特性的影响。结果表明：短期内秸秆粉碎程度对秸秆分解速率影响不大，但粉碎秸秆在试验后期分解速率明显高于长秸秆，氨化措施可显著加快秸秆的分解速率；粉碎秸秆对土壤体积质量的减小作用明显较长秸秆为好，在整个试验期，粉碎氨化秸秆处理的土壤体积质量均显著低于同时期其他处理；各处理土壤持水能力差异不大，但粉碎氨化秸秆能明显增强土壤耐旱性。该结果为探索一种能最大效益发挥秸秆改良土壤作用的秸秆还田新方式提供了一定的参照。

Effects of pulverized and ammoniated straw on soil bulk density and soil water-holding characteristics

In order to resolve the problems of slow straw decomposition, crop pests and lack of nitrogen during the straw returning, indoor soil columns experiments were conducted and effects of the soil decomposition rates of powdered straw with different C/N ratios on soil bulk density, soil water holding capacity were analyzed. The results showed that the powdered size of straw had little effect on its decomposition rate in the short term, while the decomposition rate of powdered straw was significantly higher than that of long straw at the later stage. Thus ammoniation could significantly speed up the decomposition rate of straw. Powdered straw decreased soil bulk density more significantly than long straw. Throughout the whole experiment, the soil bulk density of straw treated with powdered and ammoniated straw was significantly lower than that of other treatment after the same incubation. The water-holding capacity of all the straw utilization treatments has little difference, however the powdered and ammoniated straw could significantly increase soil drought tolerance. This research can provide a theoretical basis for exploring a new way of straw returning to get the maximum benefit in soil improvement.