广西大明山格木天然林土壤化学性质的垂直变化

Vertical variation of soil chemical properties in natural forests of Erythrophleum fordii in Damingshan Moutain, Guangxi

格木Erythrophleum fordii属国家二级重点保护植物,亦是我国热带、南亚热带地区一个重要的珍贵用材树种。本研究以我国天然分布海拔跨度最大的广西大明山格木天然林为对象,分析其土壤化学性质随海拔梯度的变化规律。结果表明:土壤pH值随土层深度的增加而上升,随海拔上升而下降,交换性酸和交换性铝含量的变化规律则与pH值相反,中、上层交换性酸含量在海拔间差异显著(P<0.05),且与海拔极显著正相关(P<0.01);上层(0～20 cm)土壤的pH值、交换性H+和交换性Al3+含量均与海拔相关极显著。土壤养分含量基本上随土层加深而下降,其土层间的差异随海拔升高呈增大的趋势。土壤综合肥力随海拔升高而增加,与海拔呈极显著正相关,且与土壤有机质含量相关显著。研究为格木天然资源保护提供科学依据。

Erythrophleum fordii is one of national second key protected tree species, and is an important valuable timber species in tropical and warm subtropical zones of China. The soil chemical properties in the natural forests of E. fordii were investigated in Danigshan Mountain where the altitude span of its natural distribution was the largest, and the effects of altitude on soil chemical properties were analyzed. The results showed that the soil pH value increased as the soil depth increased, and decreased as the altitude rose, while the contents of exchangeable H＋ and A13＋ changed in contrast to pH value, the contents of exchangeable H＋ of top-layer （0-20cm） and middle-layer （20-40cm） soils were in significant difference among the altitudes, and were correlated significantly with the altitudes; the pH value, contents of exchangeable H~ and A1~＊ of top-layer soil were all remarkably correlated with the altitudes; the soil nutrient content was basically decreased with the depth, the difference between layers increased with the increase of altitude; the soil organic matter and integrated soil fertility index was in closely significant and positive correlation with the altitude, and other soil chemical properties mostly decreased initially and then increased with increase of altitude, which were not significantly correlated with altitude. The findings can provide some evidences for further protection ofE. fordii.