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采用样方法对延安市张梁试区退耕地自然恢复过程中植被组成及其多样性特征进行了调查研究 ,结果表明 :1退耕地自然恢复形成的自然植被群落共有 5 8种植物 ,分属于 1 9个科 ,以菊科和禾本科植物最为丰富 ;2当年退耕地、1 a退耕地、2 a退耕地、5 a退耕地和 1 3a退耕地的植物群落的 Simpson多样性指数分别为 0 .899、0 .793、0 .80 8、0 .936和 0 .946,Shannon- Weiner信息统计指数、Pielou均匀度指数的变化趋势和 Simpson优势度指数基本相似 ;地上部分生物量分别为 1 .845、4.5 39、5 .35 1、3.875、4.65 0 t· hm-2 ;地下部分生物量分别为 0 .0 38、 0 .488、0 .5 63、1 .91 3和 2 .0 63t· hm-2 ;地下 /地上生物量比值分别为 0 .0 2、0 .1 1、0 .1 1、0 .49和 0 .44。 3植物生活型当年退耕地主要以 1年生植物为主 ,占 62 .5 % ;5 a、1 3a退耕地均以地面芽植物为主 ,所占比例分别为 48.3%、46.9%。
The sampling method was used to investigate the composition and diversity of vegetation during the natural restoration process of the reclaimed farmland in Zhangliang County, Yanan City. The results showed that: 1 The natural vegetation community formed by the natural restoration of cultivated land has a total of 58 species belonging to 1 9 families, most of which are Compositae and Poaceae; 2 Simpson diversity index of plant communities returning to cultivated land, reforested land for 1 year, reforested land for 2 years, reforested land for 5 years and rehabilitated land for 13 years were 0, respectively. 899,0 .793,0 .80 8,0 .936 and 0.946, Shannon-Weiner information statistical index, Pielou evenness index trends and Simpson dominance index are basically similar; above-ground biomass were 1. .845 , 4.5 39.5.35 1,3.875,4.65 0 t · hm-2, respectively. The biomass of the underground part was 0.038, 0.488, 0.563, 1.91 3 and 2.063 t · hm -2, and the ratios of aboveground biomass to aboveground biomass were 0 .0 2,0 .1 1,0 .1 1,0 .49 and 0 .44, respectively. 3 Plant life In the same year, mainly 1-year-old plants were the main land for returning land for cultivation, accounting for 62.5% of the total. The land-use herbals were the main types of land for returning cultivated land in 5 and 13 years, accounting for 48.3% and 46.9% of the total.