Soil Physical Properties Affecting Soil Erosion in ...（土壤物理性质影响水土流失u2026u2026）.pdfVIP

Soil Physical Properties Affecting Soil Erosion in Tropical Soils Deyanira Lobo Lujan1 Facultad de Agronomia, Instituto de Edafologia, Universidad Central de Venezuela, Maracay, Venezuela Lecture given at the College on Soil Physics Trieste, 3-21 March 2003 LNS0418021 1 lobod@agr.ucv.ve Soil Physical Properties Affecting Soil Erosion 233 INTRODUCTION The total vegetated land area of the earth is about 11,500 hectare. Of this, about 12% is in South America. Of this, about 14% is degraded area. Water erosion, chemical degradation, wind erosion, and physical degradation have been reported as main types of degradation. In South America water erosion is a major process for soil degradation. Nevertheless, water erosion can be a consequence of degradation of the soil structure, especially the functional attributes of soil pores to transmit and retain water, and to facilitate root growth. Climate, soil and topographic characteristics determine runoff and erosion potential from agricultural lands. The main factors causing soil erosion can be divided into three groups • Energy factors: rainfall erosivity, runoff volume, wind strength, relief, slope angle, slope length. • Protection factors: population density, plant cover, amenity value (pressure for use) and land management. • Resistance factors: soil erodibility, infiltration capacity and soil management. The degree of soil erosion in a particular climatic zone, with partic