Soil degradation
Soil degradation involves a number of physical, chemical and biological processes, which may act singly or jointly. In our state, soil erosion by water due to intense storms and soils with poor surface structural stability are the most obvious forms of land degradation. The other forms of degradation seen in our state are salinisation, alkalisation, laterisation and inundation of the total area of 18.52 million hectares in 14 districts surveyed so far, 19.6% suffers from soil degradation of one type or the other.
Current records indicate that 1,14,000 hectares of land are affected by water logging and salinity in Guntur and Prakasam districts under the Nagarjuna sagar Right Bank Canal Command. More than 60,000 hectares are alkaline in the districts of Anantapur, Kurnool, Medak, Nalgonda and Mahaboobnagar.
Salt affliction in soils may occur as a result of a variety of causes,
namely, capillary rise from subsoil containing salt, indiscriminate use
of canal water for irrigation, weathering of rocks in salts transported
by rivers from upstream regions to plains, salt impregnated sands transported
by coastal winds, in-site decomposition of soil minerals and intrusion
of sea water. The extent of saline and alkaline tracts in irrigated areas
(under canal and tank or reservoir command areas) is about 5,30,000 hectares.
There is a need to integrate findings of studies on large dams and reservoirs with the soil studies in catchment areas. Also, there are not many studies as yet on the result of non-point pollution caused by atmospheric pollutants or chemicals used as fertilisers or pesticides on the soils. No one can deny the impact these have had on our soils. This is a gap area that needs to be filled in the years to come.