By following different agronomic
practices we can reduce soil erosion, increase
moisture-holding capacity of soil and can minimize
problems like water logging, soil salinization etc.
Following
agronomic practices are performed to achieve the
above-mentioned objectives.
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CONTOUR- FARMING: Generally, as the rain falls, a
lot of runoff is generated which generally leads to
soils erosion on its way downward. This removes the top
fertile soil along with soil nutrients and plant seeds
thus leading to scanty and uneven growth of crop.
To avoid
this a simple practice of farming is done across the slope
so that there are no steep slopes on the field. The
ridges and furrows thus formed act as continuous barrier
to the free movement of water downwards thus provides more
infiltration time. Hence, the removal of soil along with
nutrients is checked to a great extent leading to
increment in soil fertility and crop yield.
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MULCHING PRACTICE: Mulching is one of the simplest
and beneficial practices for soil and water
conservation. Mulch is simply a protective layer of
material that is spread on top of the soil to prevent it
from blowing and being washed away. Mulch can either be
organic-such as grass clippings, straw, bark chips and
similar materials or inorganic such as stones, brick
chips and plastic. Conservation tillage is a common
practice that creates mulch on the soil surface. It
leaves the crop residue on the top of the soil as
mulch. The mulching practice yields following benefits:
i) Protects
the soil from erosion.
ii) Conserve moisture in soil thus saving the need for
frequent irrigation.
iii) Reduce compaction of soil due to impact of heavy
rains.
iv) Maintains a more even soil temperature.
v) Prevents weed growth to check loss of soil nutrients.
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ENHANCING THE GROWTH OF SPECIFIC CROPS: Enhancing
the growth of specific crops which provide the maximum
cover, reduce runoff and soil loss e.g. legume crops in
general furnish a better cover and hence better
protection to cultivated land against erosion than
ordinary cultivated crops. These may vary from region
to region depending upon topographical and climate
conditions.
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STRIP
CROPPING: It is a combination of contouring and crop
rotation in which alternate strips of row crops and soil
conserving crops (sods) are grown either at right angles
to the direction of the prevailing wind, or following
the natural contours of the terrain to prevent soil
erosion of the soil. When soil is detached from the row
crops by the forces of wind or water, the dense soil
conserving crops traps some of the soil particles and
reduces wind translation and/or runoff.
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MIXED
CROPPING: In this practice two or more crops are
grown in the same field at a particular time. Some of
the benefits of mixed cropping are a better and
continuous cover of the land, good protection against
the beating action of the rain. The different crops
grown in mixed cropping have their roots at different
depths holding the soil more firmly thus preventing soil
erosion.
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These
measure play an important role in soil and water
conservation. These are used in conjugation with
agronomic practices when they alone are not much
effective. The main principles of mechanical measures
are:
(i)
To facilitate infiltration by increasing the time
of concentration.
(ii)
To breakup a long slope into several short ones to
decrease velocity of runoff.
Major
mechanical measures to control soil and water conservation
are given as under:
-
CONTOUR-BUNDING: In this practice small bunds are
constructed at regular intervals across the slope of the
land. This practice is very useful in arid and
semi-arid areas with high infiltration and permeability
rates.
-
SUBSOILING: It is basically a primary tillage
operation, which consists of break opening the soil
structure up to a depth of 30 to 60 cm. This practice
facilitates greater infiltration rates and moisture
holding capacity of the soil.
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BASIN
LISTING: In this method of soil and water
conservation basins are constructed using a special
implement called basin-lister. These basins are
constructed across the slope. Basin listing provides
maximum time to rain water for infiltration into the
soil.
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BENCH
TERRACING: In this practice a series of platforms
are constructed having suitable vertical drops. The
range of vertical drop may vary from 2 to 6 feets
depending upon prevailing conditions. The capital cost
of bench- terracing is more than that of bunding
initially but in longer run it proves economical.
By
above-mentioned agronomic and mechanical measures, we can
have efficient soil and water conservation.
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