SOIL CONSERVATION

SOIL CONSERVATION
For prevention and control of soil erosion, two types of measures are undertaken: agronomic and mechanical.

AGRONOMIC MEASURES These include various meth­ods of crop cultivation to ensure protection of the top soil. The idea is to help intercept raindrops and reduce the splash effect, obtain a better intake of water rate by the soil by improving the content of organic matter and soil structure, reduce the overland runoff through contour cultivation, mulches, dense growing crops, strip cropping and mixed cropping.

Contour Farming When the soil cannot absorb all the rain that falls on it then the excess water flows down the slope under the influence of gravity. If farming is done up and down the slope, the flow of water is accelerated as each furrow serves as a rill. Major part of the rain is drained away and the top fertile soil is washed off. All this results in a scanty and uneven growth of crops.

A simple practice of farming across the slope keeping the same level as far as possible has many beneficial effects. The ridges and rows of plants placed across the slope form a continual series oI-miniature barriers to the water moving over the soil surface. Their effect is great in reducing run­off, soil erosion and loss of plant nutrients.

Mulching Mulches prevent soil from blowing off and being washed away, reduce evaporation, increase infiltra­tion to keep down weeds, improve soil structure and increase crop yields.
Strip Cropping It is another form of controlling the runoff erosion and thereby maintaining the fertility of soil. Strip cropping employs several good farming practices such as crop rotation, contour cultivation, stubble mulching and cover cropping. Strip cropping includes contour strip crop­
ping, field strip cropping, wind strip cropping and perma­nent or temporary buffer cropping.
Contour strip 'cropping involves growing a soil-expos­ing and erosion-permitting crop in strips of suitable widths across the slopes on contour, z.lternating with strips of soil­protecting and erosion-resisting crops. It shortens the length of the slope, checks the movement of runoff water and helps to desilt it, and increases the absorption of rainwater by the soil.
Wind strip cropping consists of planting tall growing crops and low growing crops in alternately arranged straight and long but relatively narrow parallel strips, laid out light across the direction of the prevailing wind regardless of the contour.
In permanent buffer strip cropping, the strips are established to take care of the steep or highly-eroded slopes in fields under contour strip cropping. The strips are generally legumes, grasses or shrubs.

Mixed Cropping The important objectives of mixed cropping are a better and. continuous cover of the land, good protection against the beating action of the rain and good protection against soil erosion. The line sowing of mixed crops gives rise to the practice of intercropping.