水稻脆性秸秆降解特性及其对土壤团聚体的影响

Degradation characteristics of rice brittle straw and its effect on soil aggregates

水稻秸秆降解效率是衡量秸秆还田利用率的重要指标,脆秆水稻秸秆易破碎,在秸秆还田中具有重要应用价值。以脆秆水稻品种科辐粳7号的秸秆为研究对象,以扬粳113为对照,通过土壤降解(有氧+厌氧)和酸碱酶解处理揭示脆性秸秆的降解特征,明确降解后的秸秆对土壤结构的影响,为脆秆水稻的应用提供理论支持。研究发现通过酸性降解处理,科辐粳7号的茎秆、叶鞘以及叶片的降解率较对照品种扬粳113秸秆分别提高了15.11%、5.66%、9.27%(P<0.05),碱性降解处理分别提高了13.18%、12.31%、11.01%(P<0.05)。土壤降解试验结果显示,科辐粳7号秸秆在质量损失、纤维素降解和半纤维素降解方面显著高于扬粳113秸秆,降解后土壤平均重量直径显著大于扬粳113秸秆,土壤破坏率显著低于扬粳113秸秆。研究结果显示,科辐粳7号的秸秆降解率比常规水稻品种显著提高,同时有利于土壤结构的改善,对于提高秸秆还田的效率十分关键。

The degradation efficiency of rice straw is an important indicator to measure the utilization rate of straw returning to the field.The brittle straw rice straw is easy to break and has important application value in returning straw to the field.The study aimed to determine the straw degradation characteristics of a brittle rice cultivar‘Kefujing 7’;and investigate the effects on soil aggregates.Rice cultivar‘Yangjing 113’was treated as the control cultivar.Straw degradation characteristics were assessed under aerobic,anaerobic,acid enzyme induced,and base enzyme induced degradation conditions,respectively.The results showed that,the degradation rates for the stem,leaf sheath,and leaf of‘Kefujing 7’were 15.11%,5.66%and 9.27%greater than those of the control cultivar(P<0.05)under acid enzyme induced degradation conditions,respectively;while they were 13.18%,12.31%and 11.01%greater than those of the control cultivar(P<0.05)under base enzyme induced degradation conditions,respectively.The mass loss,cellulose degradation rate,and hemicellulose degradation rate for the straw of‘Kefujing 7’were significantly greater than those of the control cultivar.At the end of the degradation experiments,mean weight diameter of the soil was significantly greater in the‘Kefujing 7’treatment than in the control test;while percentage of aggregate destruction of the soil was significantly lower in the‘Kefujing 7’treatment than in the control test.Overall,compared with the control cultivar,the studied brittle rice cultivar‘Kefujing 7’has greater straw degradation rates and can improve soil structures,which was critical to improving the efficiency of returning straw to the field.