重庆缙云山楠竹林土壤水分物理性质和氮素研究

Study on Physical Properties and Nitrogen of Soil Under Phyllostachys pubescens Stand in Jinyun Mountain in Chongqing

以重庆缙云山国家级自然保护区的楠竹林为研究对象,并以广泛分布的常绿阔叶林作为对照,对楠竹林和常绿阔叶林内土壤第1层表土（A）0-5cm,第2层（B）20-30cm,第3层（C）50-60cm的土壤容重等土壤水分物理性质、全氮、有效氮进行了测定。结果表明：随着土层深度、土壤容重的增加,阔叶林的第2、3层高于楠竹林;土壤孔隙度随着土层的增加而减小,楠竹林土壤孔隙度高于阔叶林;土壤毛管持水力、田间持水力、自然含水量阔叶林的表层大于楠竹林,楠竹林的第2、3层高于阔叶林;楠竹林的土壤质地较阔叶林疏松多孔,渗水、保水效果好;土壤全氮、有效性氮随土层的增加而减小,阔叶林表土层稍高于楠竹林,楠竹林第2、3层高于阔叶林。

Taking the soil layer in Phyllostachys pubescens stand in Jinyun Mountain in Chongqing as study object and taking broad-leaved forest which was widely distributed in Jinyun Mountain as reference.Soil bulk density,soil porosity,holding water capacity,total nitrogen and valid nitrogen were studied in the first surface（A）0-5cm,the second layer（B）20-30cm,and the third layer（C）50-60cm.The results showed that with increasing of soil layer,soil bulk density increased,but the second and the third layer were higher in broad-leaved stand than that in Phyllostachys pubescens stand.With increasing of soil layer,soil porosity deceased,soil porosity in Phyllostachys pubescens stand was higher than that in broad-leaved forest.Soil water holding capacity,field water holding capacity,and natural water content in broadleaved forest were greater than their in Phyllostachys pubescens stand,while the second and the third layer in bamboo stand were higher than that in broad-leaved forest.Soil texture in bamboo forest were looser,more porous and more permeable than that in the broad-leaved forest,the effect of water preserve on Phyllostachys pubescens stand was slightly higher than that in broad-leaved forest,soil total nitrogen,available nitrogen decreased as the soil increased,total nitrogen,available nitrogen in broad-leaved forest were slightly higher than that in bamboo forest,the second and third layer in bamboo forest were higher than that in broad-leaved forest.