煤矿区不同复垦年限的土壤有机碳矿化和酶活性特征

为了解煤矿区长期复垦的生态效应，在晋西北安太堡矿区不同复垦年限的样地采集土壤样品，研究土壤中w（SOC）、w（易降解碳1）、w（易降解碳2）和w（TN）以及有机碳矿化速率和酶活性随复垦年限的变化趋势.结果表明:① 随着复垦年限的延长，土壤容重、pH和w（易降解碳1）显著降低，而w（SOC）、w（TN）、w（易降解碳2）、有机碳矿化潜势和累积量及酶活性均呈增加趋势，复垦年限为23 a的土壤中w（SOC）和w（TN）的最高值分别为22.67和1.21 mg/g；② 相较于土壤中w（SOC）和w（TN），w（易降解碳2）、有机碳矿化潜势和酶活性随复垦年限延长的变化更为显著，其中过氧化氢酶活性随复垦年限的变幅最大，相较于活性最低样地，25 a样地的酶活性提高了232%，可达156.27 mg/（kg·h）；③ 土壤容重与过氧化氢酶、蔗糖酶活性均呈显著负相关，与多酚氧化酶活性呈正相关.pH与w（易降解碳1）、多酚氧化酶活性均呈显著正相关，而与蔗糖酶活性呈负相关；④ 主成分分析表明，土壤综合肥力指标随复垦进程的推进逐年提高，从-1.19提高至0.86，综合肥力指标和复垦年限间的相关系数可达到0.987（P < 0.001）.可见，综合肥力指标可更全面地指示生态修复进程中的土壤演替进程. 

Characteristics of Soil Organic Carbon Mineralization and Enzyme Activities in Coal Mining Area after Different Reclamation Times

Ecological restoration is important for mining areas. However, the succession of soil fertility with different reclamation times remains unknown. We collected soil samples from reclaimed mine sites with different reclamation times in Antaibao coal mining area, in northwest Shanxi. Soil liable carbon, organic carbon mineralization and enzymes were studied with reclamation time, which is important to evaluate the ecological effects of reclamation in the future. The results indicated:(1) Soil physical-chemical characteristics, liable carbon, carbon mineralization and four enzyme activities under different reclamation times (from 10 to 25 years) were tested in Antaibao mining area, Shanxi Province. Soil bulk density, pH and liable carbon 1 decreased with reclamation time, but soil organic carbon, total nitrogen, liable carbon 2, carbon mineralization cumulative quantity and potential, and enzyme activities increased with reclamation time. The highest soil organic carbon (SOC) and total nitrogen (TN) were respectively 22.67 mg/g and 1.21 mg/g in the 23-a site. (2) Compared to SOC and TN, the more significant improvement patterns with reclamation years were found in liable carbon 2, carbon mineralization cumulative quantity and potential, and enzyme activities. Catalase under the 25-a site was 232% higher than in the 12-a site, reaching 156.27 mg/(kg·h), which indicated the most evident variation with reclamation time. (3) Soil bulk density demonstrated significantly negative correlation with sucrose and catalase enzymes, but positive correlation with polyphenol oxidase activity. Soil pH correlated significantly with liable carbon 1, polyphenol oxidase and sucrose. Soil urease did not correlate with any physical-chemical characteristics. (4) The integrated fertility index analyzed through Principal Component Analysis improved with reclamation time, and the highest and lowest integrated fertility indexes were 0.86 and -1.19 in 25-a and 10-a reclaimed sites, respectively. Reclamation time was strongly correlated with the integrated fertility index, with coefficient 0.987 (P<0.001), which indicated that the integrated fertility index is a compressive index for assessing soil quality during ecological restoration processes.