Influence of Enclosure Regime on Soil Properties of Forest Land in Zigui County in Three Gorges Reservoir Area

不同封育方式对三峡库区秭归县林地土壤性质的影响

[Objective] This study aims to explore the influence of enclosure regime on the soil properties of forest land in Zigui County in the Three Gorges Reservoir Area. [Method] We collected soil from closed forest, forest converted from farmland, and natural secondary forest in Zigui County, and measured soil texture, bulk density, porosity, organic matter, maximum water holding capacity,water content, and content of total nitrogen, total phosphorus, total potassium,alkali-hydrolyzable nitrogen, available phosphorus, and available potassium.The findings were expected to lay a theoretical basis for forest enclosure in the Three Gorges Reservoir Area. [Result] The proportion of sands and soil bulk density in natural secondary forest were significantly lower than those in forest converted from farmland and closed forest, and the soil porosity, organic matter content, maximum water holding capacity, and overall nutrient content were significantly higher than those of the rest two forests. Soil organic matter was in significantly positive correlation with soil water holding capacity, total N,total K content, alkali-hydrolyzable N content, and available K content, and in negative correlation with soil bulk density(P<0.05). The natural secondary forest with high organic matter content had satisfactory soil properties. [Conclusion]Soil restoration in closed forest and forest converted from farmland lagged behind, and it took a long time for the improvement and restoration of the soil.

为探明不同封育方式对三峡库区秭归县林地土壤性质的影响,采集秭归县封山育林、退耕还林以及天然次生林保护区域的不同林地土壤样品,对其土壤质地、容量、孔隙度、有机质、最大持水量、含水量以及土壤养分(全氮、全磷、全钾、碱解氮、速效磷、速效钾)进行分析。结果表明天然次生林的沙粒占比和土壤容重显著低于退耕还林和封山育林,且土壤孔隙度、土壤有机质、最大持水量、土壤整体养分要显著高于其他两种封育方式。从整体上看,三种封育方式的土壤性质为天然次生林>封山育林>退耕还林。相关性分析表明,土壤有机质含量与全N、全K、碱解N、速效K以及土壤最大持水量呈显著正相关,与土壤容量呈显著负相关(P <0.05)。综上所述,天然次生林高的有机质含量使土壤具有更优良的理化性质。封山育林和退耕还林的土壤恢复存在着一定的滞后,土壤的改良和恢复需要更长时间来完成。