Agroclimatic considerations in planning conservation-effective farming systems in the semi-arid tropics
1988
Virmani, S.M.
Soil erosion is a process of detachment and translocation of soil particles from one location to another. The meteorological elements play very important role in this process. If the erosion is caused due to wind, a complete knowledge of the seasonality, direction, speed and wind run are important for development of conservation techniques for wind erosion. In the paper the wind data for Niamey in Niger and analyzed as an example and conclusions drawn on the need, spacing and effective height of the wind breaks for minimizing the soil erosion due to wind in this Sahelian location. The climatological data of Hyderabad, India are analyzed for developing an effective land use system for minimizing soil erosion losses due to rainfall in this semi-arid tropical location. Long term results of a watershed based soil and water conservation system for Vertisols and Alfisols are presented. It has been found that by creating small agricultural watersheds (size 1.5-15 ha), by smoothing the soil to give a 0.4-0.8 % grade, by laying out broadbed and furrow systems along the contour, by incorporating the drainage system through grassed water-ways, and by including crops in the cropping systems whereby a LAI of about 3 is built up within 6-8 weeks after planting an effective soil and water conservation can be achieved in Vertisols. The paper shows that a thorough knowledge of the rainfall and soil moisture characteristics is necessary for transfering this technique to other parts of the semi-arid tropical world.
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