干旱荒漠区退耕地植被演替及土壤水分变化

Characteristics of Vegetation Succession and Soil Moisture in Abandoned Cropland of Arid Desert Region

采用时空互代法,以不同退耕年限退耕地为研究对象,对27个样方植被群落特征和土壤含水量变化特征进行描述性统计分析,使用多元线性回归探究植物演替和土壤水分之间的关系。结果表明:(1)退耕18a间,退耕地植被群落自然演替经历了一年生草本为绝对优势种—一年生和多年生草本竞争存在—灌木开始出现并逐渐成为优势种的演替过程,物种Margalef指数和Shannon-Wiener指数均出现增大的趋势。(2)土壤水分随着退耕年限的增加也有所增加,且同一退耕年限内,随着土壤深度增加,土壤水分亦逐渐增加。(3)土壤水分对物种Margalef指数、Shannon-Wiener指数具有极显著影响,相比于其他土层,深度为40~50cm的土层对植被生长和演替的贡献最为显著。

In this study,27 samples from cultivated land abandoned for different years in Minqin,Gansu were surveyed by using the method of space-time interchange.Vegetation community characteristics and soil water content were analyzed by descriptive statistical analysis,and the relationship between plant succession and soil moisture was explored by multiple linear regression.The results showed that：（1）During the 18 years of natural succession of abandoned land,the natural succession process of the abandoned farmland community was as follows：mixed herbs and shrubs-single herbaceous herbs-mixed annual and perennial herbaceous community-shrub species increase and gradually the dominant species.The diversity and richness index of the species increased during the 18 years.（2）Soil moisture increased at different soil depths and gradually increased with the increase of soil depth during the same time.（3）Soil moisture has a significant effect on species Margalef index and Shannon-Wiener index.Compared with other soil layers,the soil layer of 40-50 cm depth has the most significant contribution to vegetation growth and succession.