基于RUSLE模型的云南省土壤侵蚀和养分流失特征分析

Characteristics of Soil Erosion and Nutrient Loss in Yunnan Province Based on RUSLE Model

准确评估区域土壤侵蚀和养分流失空间分布特征,是开展区域水土保持规划和生态治理的基础。基于GIS空间分析技术和RUSLE模型,对云南省土壤侵蚀和养分流失特征进行定量化分析。结果表明:云南省土壤侵蚀面积为1835.91×10^(4)hm^(2),占总面积的48.07%,平均侵蚀模数为15.65 t/(hm^(2)·a),土壤侵蚀以微度侵蚀、轻度侵蚀为主,但极强烈侵蚀、剧烈侵蚀是区域侵蚀产沙的主要来源。滇西南区土壤侵蚀强度较大,而滇西北区土壤侵蚀强度较小。区域土壤侵蚀主要发生在夏季,旱地是区域侵蚀产沙的主要策源地。流失土层厚度集中分布在0~2 mm/a,平均土层流失厚度为1.19 mm/a。土壤有机质(SOM)、全氮(TN)、速效钾(AK)、有效磷(AP)的平均流失模数分别为820.00,55.19,3.32,0.32 kg/(hm^(2)·a),4种养分流失量空间分布均存在一定的聚集特征,总体表现为滇西区等西部区域大于东部区域。研究结果可为云南省水土保持规划和水土流失生态环境建设提供科学依据。

Accurate assessment of spatial distribution characteristics of soil erosion and nutrient loss is the basis of regional soil and water conservation and ecological environment governance.Based on GIS spatial analysis technology and RUSLE model,soil erosion and nutrient loss were quantitatively evaluated in Yunnan Province.The results showed that the soil erosion area was 1835.91×10^(4) hm^(2)in Yunnan Province,accounting for 48.07%of the total area,and the mean annual erosion modulus was 15.65 t/(hm^(2)·a)with a total of 597.52×10^(6) t/a of potential soil loss.The intensity of soil erosion was mainly micro-erosion and mild erosion,but extremely strong erosion and severe erosion were the main sources of sediment yield.The soil erosion intensity was higher in southwestern Yunnan and lower in northwestern Yunnan.Soil erosion mainly occurred in summer(June-August),and dry land was the main source of sediment yield.The thickness of the lost soil layer was mainly distributed between 0 and 2 mm/a,and the average value was 1.19 mm/a.As the thickness of the lost soil layer increasing,the proportion of the corresponding area presented a decreasing trend.The average loss modulus of soil organic matter(SOM),total nitrogen(TN),available potassium(AK)and available phosphorus(AP)was 820.00 kg/(hm^(2)·a),55.19 kg/(hm^(2)·a),3.32 kg/(hm^(2)·a),0.32 kg/(hm^(2)·a),respectively.The spatial distribution of the four nutrient losses had certain aggregation characteristics,and the overall performance was that the western region was larger than the eastern region.These findings could provide scientific basis for water and soil conservation planning and ecological environment construction in Yunnan Province.