林分密度对马尾松林林下物种多样性和土壤理化性质的影响

Effects of stand density on understory species diversity and soil physicochemical properties of Pinus massoniana plantation

研究四川新津文峰山1057、1136、1231、1383和1515株·hm^(-2)5种林分密度的25年生马尾松人工公益林林下植物物种多样性、土壤理化性质及其之间的相关性.结果表明:共发现维管植物110种,隶属57科98属;随着林分密度的增大,林下物种呈现出阳生性→中生性→阴生性的演替格局,且不同密度对马尾松公益林土壤的全钾和有机质有显著影响,随着林分密度的增大,林下植物有机质和全钾含量均呈先增大后减小的趋势;林下植物多样性指数和土壤因子含量随林分密度增大的变化趋势大致相同,且均在密度为1136株·hm^(-2)时取得最大值.全磷、速效钾、全钾和全氮的含量与林下植物多样性指数的相关性最密切.当密度在1136株·hm^(-2)时更利于提高文峰山马尾松公益林林下物种多样性的稳定性和土壤肥力.

We analyzed understory species diversity, soil physicochemical traits and their relationships in the 25-year-old non-commercial Pinus massoniana plantations with five different stand densities, i.e., 1057, 1136, 1231, 1383 and 1515 trees·hm-2, in Wenfeng Mountain, Xinjin District, Sichuan Province, China. The results showed that a total of 110 species were found,belonging to 57 families and 98 genera. With the increase of tree density, the understory species showed a succession pattern from positive to moderate to shady. Different densities had significant effects on the contents of total potassium and organic matter in the soils. With the increase of density, the contents of organic matter and total potassium in understory vegetation first increased and then decreased. The trends of the relationship between both diversity and soil physiochemical characteristics and tree density were similar. Both of them increased with the increase of density, with the maximum value presented at the density of 1136 trees·hm-2. The concentrations of total phosphorus, available potassium, total potassium and total nitrogen was closely related to plantdiversity index. The results suggested that the density at 1136 trees·hm-2 would be more beneficial to improve the stability of species diversity and soil fertility of P. massoniana non-commercial plantations in Wenfeng Mountain.