矿区复垦土壤碳组分对外源碳输入的响应特征

Response of soil organic carbon fractions to exogenous carbon input in mine reclamation

  • 摘要: 研究外源碳输入对复垦土壤有机碳及组分的影响,对于深入探究矿区复垦土壤有机碳提升及培肥管理具有重要意义。本文依托山西省襄垣县采煤沉陷复垦区的长期定位试验,研究了矿区复垦土壤碳组分对不同外源碳(生物炭、堆肥、沼渣、牛粪与秸秆)输入的响应特征。分别在2011年与2016年对矿区复垦土壤样品进行采集,测定0~20 cm土层土壤有机碳、易氧化有机碳、活性碳库Ⅰ、Ⅱ的含量。结果表明,生物炭处理的土壤有机碳增长率和年变化量较对照(CK,无外源碳添加)分别增加101.80%和0.56 g·kg-1·a-1,且均显著高于其他有机物料处理;生物炭、牛粪处理土壤0~20 cm土层固碳量较CK分别提高100.52%和91.52%,二者间差异不显著,均显著高于其他有机物料处理,堆肥、沼渣和秸秆处理间对土壤固碳量的提升作用不显著。添加有机物料均能显著增加复垦土壤易氧化有机碳的增长率和年变化量,均表现为堆肥处理最高,较CK分别增加12.37%和0.16 g·kg-1·a-1。复垦土壤活性碳库Ⅰ、Ⅱ的增长率和年变化量均为牛粪处理显著高于其他有机物料处理。有机物料添加均能提高土壤稳定性有机碳含量,与CK相比,生物炭和牛粪处理的提高幅度最大,显著高于其他有机物料,而牛粪与生物碳之间差异不显著。生物炭处理碳库管理指数最高,分别较堆肥、沼渣、牛粪、秸秆处理提高36.30%、52.23%、41.50%、52.02%。施用生物炭、堆肥、沼渣、牛粪与秸秆都能显著提升复垦土壤各碳组分含量和碳库管理指数,施用生物炭的效果最优,因此施用生物炭可作为矿区复垦土壤有机碳提升的有效管理措施。

     

    Abstract: Studying the effects of exogenous carbon input on soil organic carbon fractions is important for understanding changes in soil organic carbon and fertilization management in the reclamation of mining areas. Based on a long-term experiment in a coal mining subsidence reclamation area in Xiangyuan County, Shanxi Province, China, this paper explored the response characteristics of the carbon fractions of reclaimed soil to the input of different exogenous carbon sources (biochar, compost, biogas residue, cow manure, and straw). Reclamation soil samples (0-20 cm) were collected in 2011 and 2016. The organic carbon, easily oxidized organic carbon, and labile carbon pool Ⅰ/Ⅱ in soil were measured. The results showed that the growth rate and the annual change of soil organic carbon with the biochar treatment increased by 101.80% and 0.56 g·kg-1·a-1, respectively, compared with the no-addition control (CK), and the increases with biochar were significantly higher than those with other organic material treatments. Compared with CK, the amounts of carbon sequestration in the biochar and cow manure treatments increased by 100.52% and 91.52% in the 0-20 cm soil layer, respectively; and the amounts of carbon sequestration in the biochar and cow manure treatments were significantly higher than those of other organic material treatments. There were no significant differences among composting, biogas residue, and straw treatments in promoting soil carbon sequestration. The addition of organic materials significantly increased the growth rate and annual change of easily oxidized organic carbon in reclaimed soil; the highest value was observed in the compost treatment, with an increase of 12.37% and 0.16 g·kg-1·a-1, respectively, compared with CK. The addition of cow dung significantly increased the growth rate and annual change of the labile carbon pool Ⅰ/Ⅱ, with a greater effect than other organic materials in reclaimed soil. The addition of organic materials also improved the stable organic carbon content of the soil. Compared with CK, the biochar and cow manure treatments showed the greatest improvement in the stable organic carbon content, with a significantly higher contribution than those of other organic material treatments. However, there was no significant difference between cow manure and biochar treatments. The carbon management index of biochar treatment was 36.30%, 52.23%, 41.50%, and 52.02% higher than that of composting, biogas residue, cow manure, and straw treatments, respectively. The application of all the exogenous carbon sources significantly improved the content of carbon fractions and the carbon management index of reclaimed soil. The application of biochar had the best effect. This indicates that biochar can be used as an effective management measure to improve the soil organic carbon of reclaimed mining areas.

     

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