南亚热带杉木和红椎林及其混交林的土壤肥力

Soil fertility of pure and mixed forest of Cunninghamia lanceolata and Castanopsis hystrix in south subtropical area

以南亚热带地区红椎和杉木纯林及其不同比例混交的5种林分类型(红椎纯林、杉木纯林及3种不同混交比例的红锥+杉木林)土壤为研究对象,通过在0~10 cm、10~20 cm、20~40 cm、40~60 cm和60~100 cm土层取样,测定土壤pH值、有机质、全氮、全磷、全钾、水解性氮、速效磷和速效钾含量,利用主成分分析和模糊数学方法,对其土壤肥力进行综合评价。结果表明:5种林分土壤pH值为3.98~4.65;随着深度的增加,土壤pH值和全钾含量整体呈增加趋势,土壤有机质、全氮、水解性氮、速效磷和速效钾含量整体呈减小趋势;不同林分类型之间土壤化学性质差异不大。Pearson相关分析显示,各土壤肥力因子之间存在着较为显著的相关关系。主成分分析和模糊数学评价方法均得出,随着深度的增加,土壤肥力呈减小趋势,红椎纯林土壤肥力较好,杉木纯林土壤肥力较差。

Five different forest types(pure Cunninghamia lanceolata forest,pure Castanopsis hystrix forest,1∶1,1∶2,1∶3 Cun.lanceolata and Cas.hystrix mixed forest)were selected to investigate soil fertility at 5 different soil layers(0-10 cm,10-20 cm,20-40 cm,40-60 cm and 60-100 cm)in the south subtropics of China.Soil fertility of these forests was assessed by principal component analysis and fuzzy mathematical evaluation method.The results were as follows:pH value ranged from 3.98-4.65 and showed an increase trend with the soil layer going deep.Total potassium content increased,with the increase of soil depth,while soil organic matter,total nitrogen,hydrolyzable nitrogen,available phosphate and available potassium decreased.The differences of soil chemical properties among different forest types were not significant.Pearson correlation analysis indicated that there were significant correlation among soil fertility factors.The results of principal component analysis and fuzzy evaluation method both suggested that soil fertility level decrease with the increase of soil depth.The soil fertility in pure Cas.hystrix forest was relatively higher,while in pure Cun.lanceolata forest was lower than that in other forest types.