华北农牧交错带退化草地土壤种子库动态变化

对华北农牧交错带不同退化演替阶段土壤种子库的数量和物种组成及与地上植被的关系进行了初步的研究,结果表明:农牧交错带草地在刈割和放牧等干扰下,发生逆行演替,土壤种子库中植物种类及种子数量呈递减的趋势,轻度退化类型土壤种子库物种组成最高,有23种植物,种子数量最多,有4 303粒,禾本科所占比例较大,为32.3%;而极度退化草地物种组成最低,有14种植物,种子数量仅有1 156粒,禾本科只占8.4%.草地逆行演替过程中植被与土壤种子库在物种组成上存在一定差别,中度退化阶段差别最大,有18种植物未在种子库中出现,极度退化阶段差别最小,有2种未在种子库中出现.

Soil seed bank dynamics of degraded grassland in the crisscross eco-zone of agriculture-animal husbandry in northern China

The dynamics of seed bank of different degraded grassland in the crisscross eco-zone of agriculture-animal husbandry in northern China was studied,and the relationship between the seed bank and above ground vegetation was discussed.The results showed that the species and seed number of soil seed bank showed a decrease pattern with retrogressive succession under different disturbances,such as mowing and grazing.In light degraded grassland,these were the highest of plant species(23) and seed number(4 303) of soil bank among other stages.The percentage of Gramineae was the highest,32.3%.But only 14 plant species and 1 156 seeds presented in soil seed bank at extreme degraded stage.The percentage of Gramineae was the lowest,8.4%.Under retrogressive succession,plant species decreased,moreover,there was certain difference of plant species in soil seed bank and standing vegetation.18 plant species can't be found in the soil seed bank of middle degrading grassland,but there were only 2 plant species at extreme degraded stage.