| 土壤碳收支对秸秆与秸秆生物炭还田的响应及其机制 |
| 摘要点击 3492 全文点击 1712 投稿时间：2014-12-02 修订日期：2015-01-23 |
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| 中文关键词 生物炭 秸秆 土壤呼吸 碳收支 微生物活性 易氧化态碳 |
| 英文关键词 biochar straw soil respiration carbon budget microbial activity easily oxidizable carbon (EOC) |
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| 中文摘要 |
| 秸秆直接还田与秸秆炭化还田是目前最主要的秸秆还田措施. 由于秸秆与秸秆生物炭结构和性质的差异以及还田过程的差异,其还田后的土壤呼吸和土壤碳收支必然有显著差异. 采用室外盆栽的方式,以地肤草为目标植物,系统研究了土壤呼吸与土壤碳收支对多种秸秆与秸秆生物炭还田的响应及其可能的机制. 结果表明,秸秆生物炭还田的土壤呼吸[均值为21.69 μmol ·(m2 ·s)-1]显著低于秸秆直接还田[均值为65.32 μmol ·(m2 ·s)-1],土壤有机碳含量(均值为20.40 g ·kg-1)和植物的固碳量(平均植物生物量138.56 g)均高于秸秆直接还田(均值为17.76 g ·kg-1和76.76 g); 考虑了生物炭制备过程的碳丢失后,秸秆生物炭还田的土壤碳收支仍显著高于秸秆直接还田,是一种较低碳的秸秆还田模式; 秸秆直接还田显著促进土壤脱氢酶活性﹑土壤β-糖苷酶活性和土壤活性微生物量,因此导致较高的土壤呼吸,而生物炭还田土壤的微生物活性普遍较低; 秸秆生物炭的易氧化态碳含量和可生物降解性均显著低于秸秆对照,表明秸秆生物炭稳定性较高,难以被土壤微生物降解利用,因此其还田后土壤微生物活性普遍较低,秸秆碳可在土壤中长期保存. |
| 英文摘要 |
| Direct straw returning and straw carbonization returning are the main measures of straw returning. Because of the differences in structure and nature as well as returning process between straw and straw biochar, the soil respiration and soil carbon budget after returning must have significant differences. In this study, outdoor pot experiment was carried out to study the response of soil respiration and carbon budget to straw and straw biochar returning and its possible mechanism. The results showed that soil respiration of straw biochar returning [mean value 21.69 μmol ·(m2 ·s)-1] was significantly lower than that of direct straw returning [mean value 65.32 μmol ·(m2 ·s)-1], and its soil organic carbon content (mean value 20.40 g ·kg-1) and plant biomass (mean value 138.56 g) were higher than those of direct straw returning (mean values 17.76 g ·kg-1 and 76.76 g). Considering the carbon loss after the biochar preparation process, its soil carbon budget was also significantly higher than that of direct straw returning, so it was a low carbon mode of straw returning. Direct straw returning significantly promoted soil dehydrogenase activity, soil β-glycosidase activity and soil microorganism quantity, leading to higher soil respiration, but straw biochar did play an obvious role in promoting the microbial activity index. Easily oxidizable carbon (EOC) and biodegradability of straw biochar were lower than those of straw, which showed that straw biochar had higher stability, and was more difficult to degrade for soil microorganisms, so its soil microbial activity was generally lower, and could be retained in the soil for a long time. |
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