The Yixing Yuantianjian small watershed is a provincial soil erosion key management area in the hilly region of southern Jiangsu. It has been implemented key national soil erosion control project for small watershed management, which is typical and representative in the region. It is important to quantitatively evaluate the soil quality of the area under different land use modes and then select suitable ecological restoration measures to promote the ecological and economic construction of small watersheds in the hilly region of southern Jiangsu. Used four types of land use (forest land, garden land, arable land and abandoned land) in the Yixing Yuantianjian small watershed as the research object, 13 soil physical and chemical property indicators were screened based on principal component analysis, correlation analysis and Norm value calculation to construct a minimum data set (MDS) for soil quality evaluation. The results showed that the variability of soil chemical indicators of land use modes was higher than that of soil physical indicators in the study area. The MDS indicators affected by soil quality in the small watershed are sand content (Sand), total nitrogen (TN), available nitrogen (AN), available potassium (AK), total soil porosity (TSP) and bulk density (BD), which provide valid information on soil quality in the area with high accuracy. The soil quality index for different land use modes in the small watershed in the hilly areas of southern Jiangsu was SQI forest land (0.83) > SQI cultivated land (0.74) > SQI garden land (0.66) > SQI abandoned land (0.46), with soil quality at a medium to high level. AN was the key factor limiting the soil quality of this watershed. This study can provide a scientific basis for soil quality enhancement and ecological restoration in the small watersheds of the southern Jiangsu hilly region.

中文翻译：

---

苏南丘陵地区小流域不同土地利用方式土壤质量评价

宜兴源天涧小流域是苏南丘陵地区省级水土流失重点治理区。实施了国家水土流失治理重点小流域治理工程，在本地区具有典型性和代表性。定量评价不同土地利用方式下区域的土壤质量，进而选择合适的生态修复措施，对促进苏南丘陵小流域生态经济建设具有重要意义。以宜兴元天涧小流域四种土地利用类型（林地、园地、耕地和撂荒地）为研究对象，基于主成分分析、相关分析和常值值筛选出13个土壤理化性质指标计算构建土壤质量评价的最小数据集（MDS）。结果表明，研究区土地利用方式土壤化学指标的变异性高于土壤物理指标。小流域土壤质量影响的MDS指标为含沙量（Sand）、全氮（TN）、速效氮（AN）、速效钾（AK）、土壤总孔隙度（TSP）和容重（BD），其中高精度地提供该地区土壤质量的有效信息。苏南丘陵小流域不同土地利用方式土壤质量指数为SQI林地（0.83）>SQI耕地（0.74）>SQI园地（0.66）>SQI撂荒地（0.46），其中土壤质量处于中优质水平。 AN是限制该流域土壤质量的关键因素。该研究可为苏南丘陵小流域土壤质量提升和生态恢复提供科学依据。