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| Land exploitation and utilization on debris-flow fan |
| Cui Peng1,2,Wang Daojie1,2,3,Zhuang Jianqi1,2,3 |
| 1.Key Laboratory of Mountain Hazards and Surface Process,CAS,2.Institute of Mountain Hazards and Environment,CAS:610041,Chengdu;3.Graduate School,Chinese Academy of Sciences,100039,Beijing:China |
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Abstract Land on debris-flow fan is the valuable resource in mountain area,but its soil layer structure and physical structure are irrational.The soil nutrient is poor,and the content of organic matter is less than 1%,the content of available nitrogen,available phosphorus and available potassium are in low to middle level.Land reclamation measures,soil amelioration measures and fertilizing measures for exploitation and utilization of debris-flow fan land are proposed according to its terrain,soil texture and nutrient characteristics and the problems in land development and utilization.The soil particles are mainly between 0.02 mm and 0.002 mm after improvement by silting fine sediment;the soil texture is improved from loamy sand to silty clay loam;the thickness of superficial soil achieves 25 cm which increases by 7 cm.The amount of soil micro-aggregates is 95.31% which increases by 56.87% compared with non-siltation land,and the micro-aggregates are mainly between 0.02 mm and 0.002 mm after silting improvement,which plays an important role in soil fertility and water conservation. The natural potential productivity of siltation lands on debris-flow fan is as high as 32 586 kg/hm2;while the natural potential productivity of new land on debris-flow fan and non-siltation lands are only 19 295 kg/hm2 and 28 299 kg/hm2 respectively.The content of fine grains of debris-flow fan lands formed by viscous debris flow is comparatively high and this kind of lands can be easily exploited into good quality and high output farmland;while the content of fine grains of debris-flow fan lands formed by sparse debris flow is comparatively low and this kind of lands are exploited with great difficulty and high cost.Newly reclamation lands(with high content of gravel) are suitable for planting fruit,watermelon,sweet potato,peanut and so on;and the lands with obvious improvement in the soil texture and fertility can grow rice and counterseason vegetables which have high benefit.But for the lands on sparse debris-flow fan which are difficult to be exploited,can grow the crop which does not demand rigorously on soil texture and just needs simple soil preparation,such as watermelon and pomegranate.
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Received: 10 December 2007
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