【摘要】 为澄清严重灌丛化草地能否自然恢复的争论性问题，从灌草植物水分利用与土壤水分变化的角度分析了鄂尔多斯高原油蒿灌丛化草地的恢复过程。结果表明，油蒿灌丛化草地围封后油蒿地上生物量由最高的231.7g/m~2下降至9.3 g/m~2，而长芒草生物量则由0上升至137.6 g/m~2;0～10 cm根系生物量显著增加，10 cm～20 cm根系显著减少，灌丛化草地恢复为长芒草为主的草地的趋势明显。随灌丛化草地恢复，表层土壤细粒物质增加，降雨向土壤深层入渗减少，表层土壤含水量增加。固定沙地油蒿群落油蒿5月和9月主要水分来源为浅层土壤水，7月主要利用深层土壤水；长芒草主要利用浅层土壤水。固定沙地长芒草群落油蒿5月和9月主要利用中层土壤水，油蒿7月主要利用深层土壤水；长芒草主要利用浅层土壤水。抗氧化酶和渗透调节物质分析显示长芒草的耐旱性高于油蒿。灌草植物水分利用差异与不同土层土壤水分变化是灌丛化草地恢复的关键驱动因素。更多还原

【Abstract】 In order to clarify whether the severe shrub-encroached grassland could restore to native grassland,the restoration process of Artemisai Ordoica shrub-encroached grassland in the Ordos Plateau,Inner Mongolia was analyzed from the points of shrub and grass water use,and soil moisture dynamics.The results showed that in the fenced plots of A.Ordoica shrub-encroached grassland,the aboveground biomass of A.Ordoica decreases from the maximum of 231.7 g/m~2 to 9.3 g/m~2,but increases from minimum of 0to 137.6 g/m~2 for Stipa bungeanas;the root biomass in 0-10 cm soil layer significantly increases,but significantly decreases in 10-20 cm soil layer,the conversion from shrub-encroached grassland to grassland dominated by S.bungeana is clear.With the restoration of shrub-encroached grassland,the fine soil material increases in the surface soil layer,and consequently infiltration of rain to deep soil layers decreases,soil moisture in surface layer increases.In the A.ordosica community in fixed sandy land,A.ordosica mainly uses shallow soil water in May and September,but deep soil water in July,while S.bungeana mainly uses shallow soil water in growing season.In the S.bungeana community in fixed sandy land,A.ordosica mainly uses middle soil water in May and September,and deep soil water in July,while S.bungeana uses water from shallow soil throughout growing season.The analysis on antioxidant system and osmotic adjustment indicates that S.bungeana has a higher drought resistance ability than A.ordosica.The difference of water use of shrub and grass species,and soil moisture change in different soil layers are the main driving forces for shrub-encroached grassland restoration.更多还原