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| 添加富镉稻草对土壤镉含量及活性动态变化的影响机制 |
| Influence mechanism of rice straw with cadmium on dynamic changes in soil cadmium content and activity |
| 投稿时间：2023-07-04 修订日期：2023-09-12 |
| DOI：10.13254/j.jare.2023.0431 |
| 中文关键词: 土壤，稻草，镉，溶解性有机质，光照 |
| 英文关键词: soil, rice straw, cadmium, dissolved organic matter, light |
| 基金项目:湖南省自然科学基金项目（2021JJ30357）；湖南省高新技术产业科技创新引领项目（2020NK2001） |
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| 中文摘要: |
| 为探究稻草还田在腐解过程中对土壤镉（Cd）含量和活性的影响机制，本研究以土壤和稻草为研究对象，通过不添加稻草（T0）和添加稻草（T1）处理进行土培试验，探究稻草及土壤中的 Cd含量变化；从稻草中提取溶解性有机质（DOM），并在黑暗和光照条件下分别设置不同浓度的 DOM 处理（CK、C1和 C2），进一步揭示稻草对土壤 Cd活性的影响及机制。结果表明，在土培试验中，土壤 pH 先升高后下降，Eh先下降后上升，稻草腐解 90 d后，有机质含量增加，稻草 Cd含量减少 27.93%，土壤总 Cd含量升高15.79%，土壤有效 Cd含量先下降后缓慢上升，较初始值降低 9.15%。对稻草腐解过程中提取的 DOM 进行表征发现，其亲水性较强、分子量较大，且含有羧基、羟基等官能团。在光照条件下，稻草DOM可以使土壤pH升高，并降低土壤有效Cd含量，且DOM浓度越高，下降得越多，C1和C2处理分别比CK处理低0.13 mg·kg-1和0.29 mg·kg-1。研究表明，富镉稻草还田在短时间内可降低土壤Cd活性，并且稻草的主要腐解产物DOM在光照条件下可抑制Cd在土壤环境中的迁移。 |
| 英文摘要: |
| To explore the variations in soil cadmium（Cd）activity and its influencing mechanism during the decomposition of rice straw after being returned to the field, this study took soil and rice straw as the research object and carried out soil cultivation experiments using treatments without（T0）and with rice straw（T1）to study the changes in the Cd concentration of rice straw and soil. Dissolved organic matter（DOM）was extracted from the rice straw and DOM treatments at different concentrations（CK, C1, and C2）set up under dark and light conditions, which further revealed the influence and mechanism of rice straw on soil Cd activity. The results showed that, in the soil cultivation experiments, the soil pH first increased and then decreased, Eh first decreased and then increased. And after 90 days of rice straw decomposition, the soil organic matter content increased; the Cd concentration of rice straw decreased by 27.93%; the total Cd concentration of soil increased by 15.79%; and the available Cd concentration of soil first decreased and then slowly increased, but was 9.15% lower than the initial value. The characterization of DOM extracted during the decomposition process of rice straw showed that the DOM of rice straw had high hydrophilicity and molecular weight, and contained functional groups, such as carboxyl and hydroxyl groups. Under light conditions, DOM could increase the soil pH and reduce its available Cd concentration, and the higher the DOM concentration, the more it decreased; the DOM concentrations of C1 and C2 were 0.13 mg·kg-1 and 0.29 mg·kg-1 lower than those of CK, respectively. This study showed that rice straw with Cd could decrease soil Cd activity in a short period of time, and DOM, the main decomposition product of rice straw, could inhibit the migration of Cd in the soil environment under light conditions. |
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