Erosion Control
Sloping land when put under cultivation are subject to accelerated soil erosion. The top fertile soil is washed away with every rain depletinh the soil fertility. in addition the rainwater does not get sufficient time to be absorbed by the soil and is washed as surface runoff.
Conservation Measures For Agricultural Lands
Sloping land when put under cultivation are subject to accelerated soil erosion. The top fertile soil is washed away with every rain depletinh the soil fertility. in addition the rainwater does not get sufficient time to be absorbed by the soil and is washed as surface runoff. Crops in such areas suffer both loss of soil fertility and loss of water. Conservation measure are therefore necessary to control soil erosion and retain as much water as possible in the soil.
Soil and water conservation measures for agricultural lands depend upon the soil type, land slope and rain characteristics of the area. the measure adoptade are broadly classified as (1)biological measures (2)engineering measures.
(1)BIOLOGICAL MEASURES
the biological measures are adopted when the land slopes are small [<2% in general ] and erosion problems are not severe. The methods used for controlling soil erosion through crops or vegetation and through agronomical measures practices are known as biological measures. it consist of (a) contour Cultivation (b)strip cropping (c)cropping system (d) Tillage practices.
(2) ENGINEERING MEASURES
the engineering measures consist of some land surface modification for retention and disposal of rainfall. The engineering measures adopted are contour & graded bunding terracing and grass water ways.
(a) BUNDING
Bunding is constucting small embankment or bunds across the slope of the land. it is an engineering soil conservation measures, used for retaining the water, creating obstruction and thus to control erosion.
By bunding practices, the entire area is divided into several small parts, thereby the effective slope length of the area is reduced. the reduction of the slope length causes not only to reduce the soil erosion but also retain the runoff water in the upstream area of the bund.
Generally, bunding partices is found most suitable for the land having the slope ranges from 2 to 10 percent. However it can also be used beyond 10 percent land slope but these must be required to provide a close spacing of bund which results high cost of construction.
CLASSIFICATION OF BUNDING SYSTEM
THE BUNDING SYSTEM ARE DIVIDED ACCORDING TO THEIR FUNCTION. IT IS GIVEN AS UNDER.
(1) Contour Bunding
(2) Graded Bunding
