自然資源部巖巖溶動力學重點實驗室

我國西南巖溶區土壤侵蝕強度分級標準研究

2011-12-29KDL 1483

Grading of soil erosion intensity in Southwest karst area of China
Abstract: The concentration of acid insolvable matter in carbonate rock is very low in Southwest area of China. Consequently, the formation of limestone soil is slow and the soil layer is usually thin on karst slope ,and the soil loss intensity is mostly weak and light. In fact , the area of rocky desertification in karst region , is continuously increasing these years , and with the soil erosion , the ecological situation is going to worse. The traditional standard for soil erosion gradation is confronted with challenge. The risk valuation and intensity classification of soil erosion in karst region should be redefinition. Depending on the factors on the limestone soil formation and carbonate rock corrosion , related data and images have been collected. With the help of ArcView312, the rate of limestone soil formation image can be produced. When the rate of limestone soil formation considered as the soil loss tolerance, a new standard for soil erosion gradation suitable to karst region was put forward. The duration of feeble, light, middle, strong , very strong , and acute soil loss gradation is <30, 30-100, 100-200, 200-500, 500-1000, and >1 000 t/ (km2?a) respectively. Meanwhile, on the basis of features of soil loss process and karst environment , four suggestions for soil conservation in karst region are also put forward: 1) depending on the karst hydrological characters , the sinkholes and dolines is the key part to prevent the soil loss, and effective measurement for soil protection should be taken ;2) on top part of karst hill , the carbonate rock is largely exposed and there is a little soil cover, the way to close hillside to facilitate afforestation should be selected; on the middle part of slope,the rocky desertification of which is middle gradation , the economic plants to increase the land productivity, should be planted; in the foothill part,there are thick soil layer, the farmland construction , modern agriculture activity and food production should be taken;3) in the karst region with thin soil layer , biogenic fence technology is recommended ; 4) the research of soil melioration technology should be strengthened.
Key words: karst environment ; carbonate rock corrosion; soil erosion; integrated control of rocky desertification
[摘? 要]? 中國西南巖溶區碳酸鹽巖成土物質先天不足,沿用水利部頒布的SL 190 —1996《土壤侵蝕分類分級標準》,顯然與巖溶區的實際情況不適應。在分析影響西南巖溶區碳酸鹽巖風化成土因素的基礎上,收集相關的資料、數據和圖層,估算西南巖溶區碳酸鹽巖的風化成土速率,并將成土速率作為土壤允許流失量,厘定西南巖溶區土壤侵蝕強度的分級標準,結果表明,微度、輕度、中度、強度、極強度和劇烈侵蝕標準分別為< 30、30~100、100~200、200~500、500~1 000、> 1 000 t/ (km2·a) 。根據西南巖溶區土壤侵蝕過程的基本特點,對該地區以后的水土保持工作提出以下建議:1) 抓住土壤侵蝕過程關鍵環節重點防治,2) 不同巖溶石漠化區采取不同水土保持對策,3) 積極推進生物籬技術,4) 加強巖溶區土壤改良技術研究,提高基本農田的生產效率。
[關鍵詞]? 巖溶環境; 碳酸鹽巖溶蝕; 土壤侵蝕; 石漠化綜合治理

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