农地退耕时程的土壤恢复度评估

通过测量土壤物理(密度、团聚体稳定性和入渗速率)、生物(微生物总量和土壤呼吸)和化学[表层土壤有机碳(SOC)]参数,对实施水土保持计划(CRP)的退耕土地、未受干扰和持续耕作的土地进行了比较,并利用时间函数来估计达到耕作前土壤质量所需的时间。结果显示,尽管实施CRP土地的土壤密度、入渗率、土壤呼吸和总有机碳(TOC)水平总体上趋向于受干扰前水平,但短期内任何参数都不足以恢复到受干扰前的水平。未耕作和实施30 a CRP的土壤团聚体稳定性和总微生物生物量没有显著差异,表明该参数在土地退耕30 a内得到了恢复。根据时间序列分析,估计需要53 a的时间才能使退耕土地的密度和土壤呼吸恢复到原状。入渗率和SOC的恢复时间最长,分别为75 a和128 a。结果表明,为了使土壤参数恢复到耕前状态,长期退耕是必要的。

Characteristics of soil enzymes and the dominant species of repair trees in the reclamation of coal mine area

In order to study the soil enzyme content at the mine reclamation area and choose a tree species with superior restoration capabilities, this paper takes Huainan Datong Mine as the study area, and five different enzymes under nine tree species as the study subject. The different enzyme activity indexes were measured, and the correlation analysis and the principal component analysis （PCA） method were applied to evaluate and screen the tree species with advanced restoration. The results demonstrate that there are some correlations among the different soil enzymes, including some very significant positive correlations among urease, phosphatase, invertase and protease. The best species in terms of repair is privet, and the worst is Haltong. This study provides a scientific basis for the selection of restoration-capable tree species in the reclamation area of the coal mine.