研究了科尔沁沙地小叶锦鸡儿(Caragana microphylla)人工固沙林在0、5、13、21和28年的一个时间序列上土壤理化性状和植物群落特征及其恢复动态。结果表明：1) 土壤肥力随着人工植被建立时间的延长而逐渐恢复，表现为土壤粘粉粒含量、持水性能、土壤有机碳（SOC）和全氮（N）含量、潜在土壤呼吸在时间梯度上的增加，以及土壤容重和pH值的下降，0～5 cm表层土壤的恢复显著高于5～20 cm土壤；2) 在人工植被建立和发育的早期阶段 (0～13年)，土壤肥力恢复的速率明显高于群落后期的演替阶段(13～28年)；3) 灌丛对土壤肥力有明显的富集效应，随着人工群落发育时间的延长，“肥岛”面积扩展，富集率降低；4) 随着土壤环境条件的改善，侵入的草本植物种类数量、植被盖度增加，简单的人工植被向复杂的灌草群落演变。
Horqin sandy land (42°41′- 45°15′ N, 118°35′-123°30′ E) is one of the typical areas of seriously degraded ecosystem characterized by sandy desertification in northern China. Reestablishing artificial vegetation on shifting sand dunes is one of the effective measures to control desertification in this region. Caragana microphylla (a leguminous shrub) artificial sand-fixing forest planted in different periods of time provides an opportunity for studying the patterns and mechanisms of restoration of soil and vegetation in seriously degraded ecosystems. In this paper, characteristics in soils and plant communities in an age sequence of 0, 5, 13, 21, and 28-year-old C. microphylla plantations were examined to assess the processes and mechanisms of restoration in soil fertility and plant species following shrub establishment. Soil samples were taken from two depths (0-5 cm and 5-20 cm) under the shrub canopy and in the mid-row location between shrubs. Some selected soil properties were measured and plant species was investigated. The results showed the following:1) Shrub establishment and development improved soil texture and water-holding capacity (WHC), enhanced organic C and total N accumulation, decreased pH and bulk density, and improved microbial activity as reflected by potential soil respiration. In an age sequence of 0-28-year-old C. microphylla plantations, silt and clay contents and WHC at the 0-5 cm depth in soils significantly increased with increasing restoration time. Soil organic carbon buildup in soils of the 0-5 cm depth under the shrub canopy increased 4.6, 13.3, 16.5, and 20.5 fold, respectively, from the non-vegetated mobile sand dunes (0.284 g·kg-1, age 0) after 5, 13, 21, and 28-years of occupancy, and in the alley, this increase was 1.9, 8.1, 11.1, and 13.3 fold, respectively. Total N accumulation followed the same pattern with respect to the plantation age. At the 5-20 cm depth, silt and clay contents, and organic C and total N levels were significantly lower than those at the 0-5 cm depth, but they were still higher than those found at corresponding depth in the non-vegetated mobile sand land (age 0). 2) The incremental rates in soil organic C and total N were faster in the early establishment stages (0-13 year) than in the late successional stages (13-28 year). 3) C. microphylla exhibited significant enrichment effect with higher C and N contents under their canopies. With increased plantation age, the area of `islands of fertility’ expanded and enrichment ratios decreased. 4) Shrub establishment and development facilitated the colonization and development of herbaceous species by ameliorating stressful environmental conditions. With the increase of restoration time, the simple artificial shrub community developed towards a complex shrubby-grass community. The restoration of soil fertility induced by re-vegetation is a complicated ecological process that is simultaneously affected by many biotic and abiotic variables. In erosion-prone Horqin sandy land, shrub establishment and development not only offered an important safeguard against soil erosion by wind, but also leaves of shrubs trapped dust materials enriched with nutrients and deposited them under the shrub canopies. The litter input and root turnover to the soil, and N fixation by C. microphylla contributed to C and N accumulation. Also, the improved microbial activity enhanced the release of nutrients from litter. Accordingly, the amelioration of soil and environmental conditions with shrub development facilitated the increase of plant species.