黄土高原子午岭地区植被恢复过程中的土壤质量评价

Evaluation of soil quality during vegetation restoration in the Ziwuling Area of Loess Plateau

选择黄土高原子午岭地区植被自然恢复1-140a不同年限的阳坡墚坡地为研究对象，通过相关性分析筛选土壤表层（0-20cm）16项表征土壤物理、化学、生物学性质的指标，运用主成分分析计算土壤质量综合指数，评价子午岭地区植被恢复过程对土壤质量的影响。结果表明：土壤总孔隙度、平均重量直径（MWD）、有机质质量分数、速效磷质量分数、蔗糖酶活性、碱性磷酸酶活性、真菌数量、微生物总量构成土壤质量评价指标体系；土壤质量综合指数随植被恢复年限的增加而增加；植被自然恢复1-140a间，土壤质量综合指数变化范围为0.1559-0.8509，较裸露休闲地增加4.2-27.5倍；根据土壤质量综合指数变化规律，可将140a植被恢复过程中的土壤质量演变过程分为3个阶段，即植被恢复初期（1-20a）的土壤质量综合指数呈快速增长，植被恢复中期（20-40a）的土壤质量综合指数呈波动性增长，植被恢复后期（40-140a）的土壤质量综合指数呈稳定增长。植被演替过程中不同植被生活型土壤质量综合指数表现为乔木林地〉灌木林地〉草地。

Taking research sites located at sunny hillslopes of natural vegetation restoration with different age （1-140a） in the Ziwuling Area of Loess Plateau as a case study, selecting sensitive indicators from 16 soil physical, chemical and biological attributes of topsoil（0- 20cm） through correlation analysis, the paper assessed soil quality index （ISQ） during vegetation restoration in the Ziwuling Area through statistic analysis method and principal component analysis. Results indicated that, during vegetation natural succession in the Ziwuling Area, soil total porosity, mean weight diameter （MWD）, organic matter, available P, invertase activity, alkaline phosphatase activity, fungi, and microbial biomass were selected as soil quality assessment indicators. Soil quality index increased with vegetation restoration during over 140 years.ISQ shifted from 0.1559 to 0.8509 during more than 140 years＇ natural vegetation succession, and ISQ was 4.2-27.5 times greater than that on bare and fallow land. Based on ISQ change trend, evolution process of IsQ could be divided into 3 stages, that were, ISQ increased rapidly at the beginning of vegetation restoration （1-20a）; ISQ increased fluctuant in the mid-term of vegetation restoration （20 - 40 a） ; ISQ increased steadily in the later period of vegetation restoration （40-140a）. For different vegetative types during vegetation restoration, ISQ followed the order： forest land 〉 shrub land 〉 grassland.