| 摘要: |
| 为进行青藏高原不同土地利用方式下土壤质量对比并研究其影响因素，以位于青南江河湖源区、藏北高原和南亚通道的三条样带为研究区，针对区域内高寒草甸、荒漠草原、农田和沙地这四种土地利用方式，采用主成分分析法建立最小数据集（minimum data set，MDS），计算土壤质量综合指数（soil quality index，SQI）并进行土壤质量评价。结果表明：（1）评价青藏高原土壤质量的MDS包括容重、有机质、全氮、全钾和有效磷，按SQI大小将土壤质量分为五级，研究区土壤质量较差，以Ⅲ、Ⅳ、Ⅴ级为主且东部土壤质量优于西部；（2）研究区土壤质量高寒草甸＞荒漠草原＞农田＞沙地，且高寒草甸土壤质量显著优于荒漠草原、农田和沙地，后三者间土壤质量差异不大，MDS中对土壤质量起主要作用的指标为有机质、全氮和有效磷；（3）在土壤质量的众多影响因素中，本文主要考虑的是植被盖度、风蚀强度和人类活动，其中高寒草甸植被盖度大，风蚀强度弱，土壤质量好，荒漠草原和沙地植被盖度小，风蚀强度大，土壤质量差，而农田土壤质量受人类活动影响。 |
| 关键词: 青藏高原 土壤质量 土地利用方式 主成分分析 |
| DOI：10.7515/JEE222059 |
| CSTR： |
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| 基金项目:第二次青藏高原综合科学考察研究（2019QZKK0306） |
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| Soil quality assessment under different land uses in Qinghai-Tibet Plateau |
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ZHAO Jin, LU Ruijie, MA Luo
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1. MOE Engineering Research Center of Desertification and Blown-sand Control, Department of Geographic Sciences, Beijing Normal University, Beijing 100875, China
2. State Key Laboratory of Surface Processes and Resource Ecology, Department of Geographic Sciences, Beijing Normal University, Beijing 100875, China
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| Abstract: |
| Background, aim, and scope The Qinghai-Tibet Plateau ecosystem is a alpine ecosystem with simple structure and poor stability. At present, most studies still focus on the typical land use type of alpine meadow, but lack of studies focus on other land use type such as farmland and sandy land. And there is relatively little comparative analysis of soil quality under different land use types. Three transect zones located in the source region of rivers and lakes on the Qinghai-Tibet Plateau, the northern Qinghai-Tibet Plateau and the South Asia channel were taken as the study areas in order to study the comparison of soil quality and its influencing factors under different land use modes the Qinghai-Tibet Plateau. Materials and methods According to the four different land use patterns of alpine meadow, desert steppe, farmland and sand land in the region, the minimum data set (MDS) was established by selecting the indexes from the various soil physical and chemical indexes by principal component analysis (PCA). The indexes were standardized according to different function models. Combined with the index weights determined by the variance of common factors, the soil quality comprehensive index (SQI) was calculated and the soil quality was evaluated. Results MDS for evaluating soil quality in Qinghai-Tibet Plateau includes bulk density (BD), organic matter (OM), total nitrogen (TN), total potassium (TP) and available phosphorus (AP). The soil quality is divided into five grades according to SQI. The soil quality in the study area is poor, mainly grade Ⅲ, Ⅳ and Ⅴ, and the soil quality in the east is better than that in the west. Discussion According to SQI, the soil quality is alpine meadow＞desert steppe＞farmland＞sandy land. The indicators that play a major role in the change of soil quality under different land use modes are OM, TN and AP. Among many factors affecting soil quality, vegetation coverage, wind erosion intensity and human activities are mainly considered in this research. Alpine meadow has large vegetation coverage and weak wind erosion intensity. So its vegetation debris input is large and the loss of fine particles is small, which make the soil quality good. Desert grassland and sandy land have small vegetation coverage, high wind erosion intensity. So the input of vegetation residue in desert grassland and sandy land is small, and the loss of fine particles is large, which make the soil quality poor. The soil quality of farmland is still poor under the condition of high vegetation coverage and low wind erosion intensity because the soil quality of farmland is mainly affected by human activities. Conclusions The soil quality in the study area is poor, and the soil quality decreases from alpine meadow to desert grassland, farmland and sandy land. The main indicators are the content of OM, TN and AP, and the influencing factors are vegetation coverage, wind erosion intensity and human activities. Recommendations and perspectives In addition to vegetation coverage, wind erosion intensity and human activities, topography, climate, hydraulic erosion and freeze-thaw erosion are also factors affecting soil quality under different land use modes, which need to be further discussed in the follow-up study. |
| Key words: Qinghai-Tibet Plateau soil quality land use types principal component analysis |
