竹林林下植物多样性与土壤水分入渗关系的研究

The Relationship between Understory Plant Diversity and Soil Infiltration in Bamboo Stands

研究分别以浙江安吉县的4种林分类型(毛竹纯林(A)、毛竹+乔木(B)、毛竹+灌草(C)、乔木+灌草(D))以及湖南炎陵县3种林分类型(毛竹+乔木、毛竹+灌草、乔木+灌草)为对象,探讨了不同类型竹林林下植物多样性与其下不同深度土壤根系重量之间的关系,以及土壤渗透速率与不同土层根系重量和土壤含水量的相关性。结果表明:(1)上述4种植被类型0～40 cm根系生物量约为40～80cm的3倍,各类型林下植物多样性与其不同土层的根系重量相关性不显著;(2)浙江安吉4种植被类型中,0～40 cm与40～80 cm土层的渗透性指标以毛竹+乔木较好,初渗率、稳渗率和平均渗透率平均分别为:15.38、5.26和8.8 mm.min-1;毛竹纯林上述3项指标较低,平均分别为:5.83、3.03和4.45mm.min-1;湖南0～40 cm土层毛竹+乔木渗透性最好,上述三项指标分别为:16.72、12.23和9.13mm/min,40～80 cm各植被类型渗透性相差不大;(3)浙江毛竹+乔木、乔木+灌草土壤含水量均随土壤深度增加而降低,毛竹纯林与毛竹+灌草土壤含水量随土壤深度增加而先降低到18%后逐渐升高最终稳定在19%;(4)土壤入渗速率与不同深度土层根系重量显著相关,但根系重量不是决定土壤渗透性能的主要因素;(5)0～40 cm土层的累计入渗量和土壤初始含水量呈典型的负相关,而40～80 cm土层的累计入渗量和土壤初始含水量没有明显的相关关系。

A field study on four different forest stand types,i.e.pure bamboo stand,bamboo and tree mixed stand,bamboo and shrub-grass mixed stand and tree-shrub-grass mixed stand was made in Anji County,Zhejiang Province.Another field study on three different forest types,i.e.bamboo and tree mixed stand;bamboo and shrub-grass mixed stand;and mixed tree and shrub-grass stand was done in Yanling County,Hunan Province.The relationship between understory plants and root weight in different soil layers was explored.The root weight and the soil water content in different soil layers were studied.The results showed that the root weight in the 0～40 cm soil layer was about 3 times as much as that in the 40～80 cm soil layer,and the correlation between understory plant diversity and root weight in the different soil layers is not significant.In Anji,the permeability in the 0～80 cm soil layer in the bamboo and tree mixed stand is the highest while that of the pure bamboo stand is the lowest among all forest types.The average values of initial infiltration rate,stable infiltration and average infiltration in the bamboo and tree mixed stand were 15.38,5.26,8.8 mm·min-1 respectively,and corresponding values for the pure bamboo stand were 5.83,3.03,4.45 mm·min-1 respectively.In Yanling,the permeability in the 0～40 cm soil layer of the bamboo and tree mixed stand is the highest,the values of above mentioned permeability indicators were 16.72,12.23 and 9.13 mm·min-1 respectively.Permeability in 40～80 cm soil layer showed almost the same pattern.Soil water content decreased with soil depth for all forest types in the Yanling.For the pure bamboo stand,soil water content decreased with soil depth until a certain value of 18%,and then remained stable at 19% with a small increase in 20～40 cm layer.The soil infiltration rate at different depths was significantly related to the weight of the roots,but root weight is not a determinant factor.The cumulative infiltration was negatively correlated with initial soil water content in 0～40 cm soil layer,although there was no obvious correlation between them in 40～80 cm soil layers.