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[目的]研究石羊河下游民勤绿洲不同年限退耕地土壤物理性质与群落特征。[方法]通过对石羊河下游民勤绿洲1a、2a、3a、4a、5a、8a、15a、24a和31a退耕地的生境和植被群落特征的分析,研究了不同年限退耕地植被群落、土壤水份、容重、孔隙度和机械组成的变化。[结果]1石羊河下游民勤绿洲退耕地在31a自然恢复过程中共出现植物32种,14科,其中灌木6种,草本26种,分别占总物种数的81.25%、18.75%;藜科(6种)、菊科(4种),禾本科(4种)、蒺藜科(3种),4科植物占总物种数的53.13%;2不同年限退耕地0~40 cm范围内土壤含水量随土层深度增加经历了先增后减的一个变化过程,土壤容重及孔隙度变化不太明显;3在退耕地0~40 cm土层范围内,各样地细砂粒的比例最大,粉粒和粘粒次之,粗砂粒的比例最小,但各粒径所占比例随退耕年限的变化不大。[结论]该研究可为石羊河下游退耕地区植被重建及生态环境建设提供借鉴。
[Objective] The research aimed to study the soil physical properties and community characteristics of abandoned farmland in Minqin Oasis in different years. [Method] Based on the analysis of habitat and vegetation community characteristics of the reclaimed land in Minqin Oases 1a, 2a, 3a, 4a, 5a, 8a, 15a, 24a and 31a of Shiyang River, the vegetation communities, soil water Parts, bulk density, porosity and mechanical composition changes. [Result] A total of 32 species, 14 families, including 6 species of shrubs and 26 species of herbs, accounted for 81.25% and 18.75% of the total species respectively during the natural restoration of 31a in Minqin Oasis, 6 species), Compositae (4 species), Poaceae species (4 species) and Chenopodiaceae species (3 species), and 4 families accounted for 53.13% of the total species. 2 Soil moisture content in 0-40 cm range The change of soil bulk density and porosity did not change obviously with the increase of soil depth. (3) Within 0-40 cm soil layer, the proportion of fine sand was the highest in all areas, Followed by clay, the proportion of coarse grit is the smallest, but the proportion of each particle size does not change much with the years of returning farmland. [Conclusion] This study can provide reference for the vegetation reconstruction and ecological environment construction in the area of returning farmland to the lower reaches of Shiyang River.