不同龄组柳杉人工林土壤肥力特征

Soil fertility characteristics of a Cryptomeria fortunei plantation in different forest age groups

为了研究林龄对柳杉人工林土壤肥力的影响,选取黔中平坝区大坡林场5个龄组(幼龄林、中龄林、近熟林、成熟林、过熟林)柳杉人工林为研究对象,对5个龄组不同土层土壤肥力进行研究。结果表明:林龄对柳杉人工林土壤理化性质有显著影响。随着林龄的增加,土壤含水量、有机质、全氮、速效氮、全钾增加,土壤容重、速效磷、全磷先降低后增加,孔隙度先增加后减小,速效钾先升高后降低再增加,pH值降低;土层对土壤酸碱度和容重没有显著影响,但对其他理化性质有显著影响。随着土层的加深,土壤含水量先减少后增加,容重逐渐增大,孔隙度逐渐减小,有机质、氮、磷、钾具有表面聚集效应。土壤各项肥力指标之间有密切联系。对不同龄组柳杉人工林的土壤肥力进行了分析评价,土壤肥力由高到低依次为过熟林>成熟林>近熟林>中龄林>幼龄林。

In order to study the effect of forest age on the soil fertility of a Cryptomeria fortunei plantation,the young,middle aged,near mature,mature,and over mature Cryptomeria fortunei forests of Pingba Dapo Forest Farm in Guizhou Province,China were chosen for study.The fertility of the 0-30 cm soil layer was analyzed.The results showed that the forest age had a significant effect on the physical and chemical properties of the soil.The soil water content,organic matter,total nitrogen,available nitrogen,and total potassium all increased with age.The soil bulk density,available phosphorus,and total phosphorus decreased first and then increased with age.The porosity increased first and then decreased with age.The available potassium increased first,then decreased,then gradually increased with age.The pH decreased with age.The soil layer had no significant effect on pH and bulk density,but had significant effects on other physical and chemical properties.The soil water content decreased first and then increased with increasing soil depth.The soil bulk density increased with increasing soil depth,whereas the porosity decreased with increasing soil depth.The organic matter(OM),nitrogen(N),phosphorus(P),and potassium(K)content also decreased with increasing soil depth.There were close relationships between the soil fertility indicators.The soil fertility of different age groups was analyzed and evaluated;the soil fertility from high to low followed the order:over mature forest>mature forest>near mature forest>middle age forest>young forest.