矿区不同复垦措施对土壤碳矿化和酶活性的影响

矿区废弃地生态退化形势严峻,生态修复已成为矿区可持续发展的主要措施,目前关于矿区复垦后土壤碳矿化和酶活性变化的研究较少。以山西省孝义市露天矿区复垦区为研究对象,植被恢复类型包括了百脉根、苜蓿、油松和柳树-圆柏混交林,并对其分别进行不施肥(对照)、无机肥、复合肥和有机肥处理,从而研究植被类型与施肥方式对矿区土壤碳矿化和酶活性的影响。结果表明,乔本比草本恢复类型的土壤有机碳矿化潜势大,不同施肥条件的土壤有机碳矿化潜势和累积量趋势基本为:对照无机肥复合肥有机肥;4种土壤酶活性因植被恢复类型和施肥处理的不同而差异显著,不同土壤酶与降解特性不同的有机碳间相关性有所不同。土壤碳矿化累积量和酶活性均受植被恢复类型、施肥处理及两者交互作用的显著影响,因此对复垦措施敏感的土壤有机碳矿化和酶活性可作为评价复垦措施的指标。

Effects of different reclaimed measures on soil carbon mineralization and enzyme actives in mining areas

Ecological degradation in the mining areas are greatly aggravated in recent decades. Ecological restoration has become the primary measure for the sustainable development, espcially in Shanxi Province where mine industry has been one of the pillar industies. Therefore, regulations were initiated to reclaim abandoned coal mining areas for agriculture and forestry in 2006. The vegetation and soil physicochemical characterics are often considered as the basic knowledge for assessing the effects of mining reclaimaed measures. However, soil carbon dynamics and enzyme activies still remain poorly understood. In this paper, we tested the effects of different regeneration scenarios and fertilizer treatments on soil organic carbon mineralization and enzyme actives in reclaimed opencast mining areas. Ecological reconstruction was initiated on the abandoned land in Xiaoyi mining area under four regeneration scenarios including Lotus corniculatus, Medicago sativa grasslands, Pinus tabulaeformis plantation, and Salix matsudana-Sabina chinensis mixed forest treated by different fertilizations including no, inorganic, organic and combination of inorganic and organic fertilizer added to soils. We analyzed the effects of regeneration scenarios and fertilizer treatments on oil organic carbon dynamics and enzyme actives, and the relationships between soil enzyme actives and different active carbon through quantitative ecology method. The major findings of the dissertation are as follows: (1) Soil organic carbon mineralization potential and cumulative carbon from herb regenerations were lower than from tree ones. Under same regeneration scenario, the order of soil organic carbon mineralization potential was no < inorganic fertilizer < inorganic + organic fertilizer < organic fertilizer. Especially, the positive effects of organic fertilizer were obvious. In addition, soil carbon-cumulative mineralization was also stimulated by fertilizer treatments. (2) The feedbacks to the regeneration scenarios and fertilizer treatments from different enzymes actives were different. There were the contrary responds to fertilizer treatments between herb and tree scenarios. Except for phlyphenol oxidase, the effects of fertilizer treatments on soil enzyme activities were positive in most cases. (3) The relationships between soil enzyme activities and carbon varied due to enzyme types and carbon activity. Positively significant correlation was demonstrated on soil sucrase and dehydrogenase (P < 0.05), however, negative correlations were shown between soil urease and oxidase (P < 0.05) /phlyphenol (P < 0.05). (4) The effects of regeneration scenarios, fertilizer treatments and their mutual actions on soil carbon-cumulative mineralization and enzyme activities were at the 0.01 levels, except that the effect of fertilizer treatments on soil phlyphenol oxidase was at the 0.05 level. Soil carbon-cumulative mineralization and enzyme activities were more sensitive to fertilizer treatments and regeneration-fertilizer interaction than soil pH, bulk density, organic carbon and nitrogen. Therefore, the sensitive diversity indices of soil carbon-cumulative mineralization and enzyme activities could be as good indictors to assess the effects of mining reclamation measures.