Soil and water are our precious heritage. Hence, it is obligatory on our part to protect and hand over these resources to further generations. It is estimated that about 50% of the cultivated area in India suffers from severe soil erosion and requires remedial measures.
•Water resources are essential for increasing and stabilizing crop production.
•Wind erosion has been responsible for destroying the valuable top soil.
Degradation of soil and water takes place with water and wind erosion
•The main cause of water erosion is unmanaged runoff.
•Runoff is the portion of the rainfall or irrigation water applied which leaves a field either as surface or as subsurface flow.
Several factors are responsible for runoff
•Climatic factors: Precipitation characteristics – duration, intensity, distribution, direction, temperature, humidity, wind velocity.
•Watershed characteristics: Geological shape of the catchments, size and shape of the catchments, topography, drainage pattern.
•Barren land without vegetation
•Sandy soil: Average rain – no problem of erosion. High intensity – More serious of less binding material i.e. fine soil particle.
•Clay soil: Ordinary rain – more runoff in moderate and steep slopes but high water holding capacity.
•Silt loam, loamy and fine sandy loam: More desirable soils from the point of view of minimizing soil erosion.
How vegetation reduces runoff
•Interception of rainfall
•Intercept, absorb the impact of raindrop
•Hindrance to runoff water slows down the rate at which travels down the slope
•Knitting and binding effect aggregates the soil into granules
•Die and decay increase pore space and water holding capacity
•One cubic meter of soil has several kilometres of root fibre
•More vegetative cover, most active soil fauna, channels of earth worm, beetles and other life
•Vegetation increases the storage capacity of the soil for rainfall by the transpiration of large quantities of moistures from the soil