If soil erosion and exhaustion are caused by
humans; by corollary, they can also be
prevented by humans. Nature has its own laws
of maintaining balance which at times are insufficient due to accelerated human activities. So we must find ways to restore this balance without affecting the ecological balance.
Soil conservation is the prevention of loss of the top most layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination. It is a methodology
to maintain soil fertility, prevent soil erosion
and exhaustion, and improve the degraded
condition of the soil. Techniques for improved soil conservation include crop rotation, cover crops, conservation tillage and planted windbreaks, affect both erosion and fertility. When plants die, they decay and become part of the soil.
Methods of Soil Conservation
Soil erosion is essentially aggravated by
faulty practices. The first step in any rational
solution is to check open cultivable lands on
slopes from farming. Lands with a slope gradient of 15 - 25 per cent should not be used for cultivation. If at all the land is to be used
for agriculture, gradient modifications should carefully be
Efforts should be made to prevent gully
erosion and control their formation. Finger
gullies can be eliminated by terracing. In
bigger gullies, the erosive velocity of water may
be reduced by constructing a series of check
dams. Special attention should be made to
control headward extension of gullies. This can
be done by gully plugging, terracing or by
planting cover vegetation.
Terracing is the practice of creating nearly level areas in a hillside area. The terraces form a series of steps, each at a higher level than the previous. Terraces are protected from erosion by other soil barriers. Terraced farming is more common on small farms and in underdeveloped areas, since mechanized equipment is difficult to deploy in this setting.
Contour ploughing orients furrows following the contour lines of the farmed area. Furrows move left and right to maintain a constant altitude, which reduces runoff. Contour ploughing was practiced by the ancient Phoenicians, and is effective for slopes between two and ten percent. Contour ploughing can increase crop yields from 10 to 50 percent, partially as a result of greater soil retention.
Perimeter runoff control
Tree, shrubs and ground-cover are effective perimeter treatment for soil erosion prevention, by impeding surface flows. A special form of this perimeter or inter-row treatment is the use of a "grass way" that both channels and dissipates runoff through surface friction, impeding surface runoff and encouraging infiltration of the slowed surface water.
Windbreaks or Shelter belts
Windbreaks are sufficiently dense rows of trees at the windward exposure of an agricultural field subject to wind erosion. Evergreen species provide year-round protection; however, as long as foliage is present in the seasons of bare soil surfaces, the effect of deciduous trees may be adequate. In arid and semi-arid areas, efforts should be made to protect cultivable lands from encroachment by sand dunes through developing shelter belts of trees and agro-forestry. Experiments have been made to stabilise sand dunes in western Rajasthan by the Central Arid Zone Research Institute (CAZRI).
Soil-conservation farming involves no-till farming, "green manures" and other soil-enhancing practices. Such farming methods attempt to mimic the biology of barren lands. Contour bunding, Contour terracing, regulated forestry, controlled grazing, cover cropping, mixed farming and crop rotation are some of the remedial measures which are often adopted to reduce soil erosion.
No-till farming and cover crops act as sinks for nitrogen and other nutrients. This increases the amount of soil organic matter. Repeated plowing/tilling degrades soil, killing its beneficial fungi and earthworms. Once damaged, soil may take multiple seasons to fully recover, even in optimal circumstances.
Cover crops such as legumes plant, white turnips, radishes and other species are rotated with cash crops to blanket the soil year-round and act as green manure that replenishes nitrogen and other critical nutrients. Cover crops also help suppress weeds.
Over-grazing in many parts of India have affected the natural cover of land and given rise to extensive erosion. It should be regulated and controlled by educating villagers about the consequences. Lands not suitable for cultivation should be converted into pastures for grazing
The Central Soil Conservation Board, set up
by the Government of India, has prepared a
number of plans for soil conservation in different
parts of the country. These plans are based on
the climatic conditions, configuration of land
and the social behaviour of people. Even these
plans are fragmental in nature. Integrated land
use planning, therefore, seems to be the best
technique for proper soil conservation. Lands
should be classified according to their
capability; land use maps should be prepared
and lands should be put to right uses. The final
responsibility for achieving the conservation of
land will rest on the people who operate on it
and receive the benefits.