To evaluate soil quality status of forest, grassland, and cropland in the southern and northern Tibetan Plateau, and to clarify the key influencing factors of productivity levels under three land use types, we measured the basic physical and chemical properties of 101 soil samples collected in the northern and southern Qinghai-Tibet Plateau. Principal component analysis (PCA) was used to select three indicators as the minimum data set (MDS) to comprehensively evaluate soil quality of the southern and northern Qinghai-Tibet Plateau. The result showed that soil physical and chemical properties of the three land use types were significantly different in the north and south. The contents of soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP) and available potassium (AK) in the north were higher than those in the south, while the contents of SOM and TN of forest were signi-ficantly higher than those of cropland and grassland in both the north and south. Soil ammonium (NH4+-N) content showed a pattern of cropland > forest > grassland, with significant difference in the south. Soil nitrate (NO3--N) content in the north and south was the highest in the forest. Soil bulk density (BD) and electrical conductivity (EC) of cropland were significantly higher than those of grassland and forest, and that of cropland and grassland in the northern part was higher than that of southern part. Soil pH of grassland in the south was significantly higher than that of forest and cropland, and that of forest was the highest in northern part. The selected indicators for eva-luating soil quality in the north were SOM, AP, and pH, and soil quality index of forest, grassland, and cropland was 0.56, 0.53 and 0.47. The selected indicators were SOM, total phosphorus (TP), and NH4+-N in the south, and soil quality index of grassland, forest and cropland was 0.52, 0.51 and 0.48, respectively. There was a significant correlation between soil quality index obtained by the total data set and the minimum data set, and the regression coefficient was 0.69. Soil quality in the north and south of the Qinghai-Tibet Plateau were grade Ⅲ, and soil organic matter was the main indicator limiting soil quality in this area. Our results provide a scientific basis for eva-luating soil quality and ecological restoration in the Qinghai-Tibet Plateau.
为了评估青藏高原南北部林地、草地和农地的土壤质量状况,明确3种土地利用方式下生产力水平的关键影响因子,在青藏高原南部和北部采集了101个(0～30 cm)土壤样品测定土壤理化性质,通过主成分分析选择3个指标作为最小数据集(MDS),综合评估青藏高原南北部土壤质量。结果表明: 3种土地利用方式下土壤理化特性在青藏高原南、北部差异显著。北部土壤有机质(SOM)、全氮(TN)、速效磷(AP)、速效钾(AK)含量均高于南部,且南北部的林地SOM、TN含量均显著高于农地和草地。土壤铵态氮(NH4+-N)含量表现为农地>林地>草地,且在南部差异显著,而南北部硝态氮(NO3--N)含量均表现为林地最高。农地的土壤容重(BD)和电导率(EC)显著高于草地和林地,且北部农地和草地的BD和EC高于南部。南部草地pH显著高于林地和农地,北部林地pH最高。北部土壤质量选取指标为SOM、AP和pH,林地、草地和农地的土壤质量指数依次为0.56、0.53和0.47;南部选取指标为SOM、全磷(TP)和NH4+-N,草地、林地和农地的土壤质量指数依次为0.52、0.51、0.48,采用全量数据集与最小数据集得到的土壤质量指数之间呈极显著相关,回归系数为0.69。青藏高原南北部土壤质量均为Ⅲ级,有机质是限制该区土壤质量的主要指标,结果可为评估青藏高原地区土壤质量和生态恢复提供科学依据。.
Keywords: Qinghai Tibet Plateau; land use pattern; minimum data set; soil quality.