question_answer 50)

  Soil erosion can be prevented by (a) raising forests                  (b) deforestation        (c) excessive use of fertilizer   (d) overgrazing by animals

Answer:

  (a) Various methods used to prevent soil erosion are 1. Intensive cropping Crops keeps the soil banded. 2. Sowing grasses and planting xerophytes Sowing grasses on barren soil or planting of xerophytes will bind the loose soil, 3. Terrace farming (terracing) in terracing the slopes are divided into a number of flat fields to slow down the flow of water. Moreover, eroded soil from upper regions of hills gets deposited in lower terraces. 4. Contour bonding Small bunds (embankments or dikes) are raised on the edges of fields to prevent loss of top soil through either wind or water. 5. Conservation tillage Instead of conventional tillage, reduced or no tillage can be practiced, 6. Wind breaks Rows of trees and shrubs are planted at right angles to the prevailing wind flow. 7. Proper drainage canals around the fields This method involves the removal of excess rain water through small drainage canals formed around the fields.