[Modellization of the physical degradation process of soils]
1995
Pla Sentis, I.
Most of the agricultural production in Venezuela, and in Latin America, is mainly based on rainfed crops, growing in areas with a high variability unreliability of rainfall, where water is the main single factor responsible both for crop production and land degradation. The main land degradation processes with direct effects on crop production are soil water erosion, soil compaction, soil sealing and crusting, and combination of them. These degradation processes generally cause negative changes on the soil moisture regime, and on the possibilities of root development. In order to get more quantitative answers in probabilities and risks of land and soil degradation and their effects on crop production or environmental damages, there is required the use of physically process-based models, where the interactions can be integrated. For that purpose it is proposed a simple simulation water balance model, based on available or easily measured climatic and soil information which is able to simulate the expected hydrological processes leading to soil degradation. The output of the model may be used to assess the intensity, timing and probabilities of conditions leading to different processes of soil degradation and their effects on crop production and environmental damages (floodings, sedimentations, land slides, etc). This information is the basis for the selection and design of sustainable systems of land use and management. The application of the model is illustrated with several examples from different agricultural areas of Venezuela, with actual or potential soil degradation problems.
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