11:32 am - Monday May 28, 2012

Soil Conservation

Soil conservation is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination. It is a component of environmental soil science.

Decisions regarding appropriate crop rotation, cover crops, and planted windbreaks are central to the ability of surface soils to retain their integrity, both with respect to erosive forces and chemical change from nutrient depletion. Crop rotation is simply the conventional alternation of crops on a given field, so that nutrient depletion is avoided from repetitive chemical uptake/deposition of single crop growth.

Cover crops serve the function of protecting the soil from erosion, weed establishment or excess evapotranspiration; however, they may also serve vital soil chemistry functions. For example, legumes can be ploughed under to augment soil nitrates, and other plants have the ability to metabolize soil contaminants or alter adverse pH. The cover crop Mucuna pruriens (velvet bean) has been used in Nigeria to increase phosphorus availability after application of rock phosphate. Some of these same precepts are applicable to urban landscaping, especially with respect to ground-cover selection for erosion control and weed suppression. soil is one of the three main natural resources alongside with water and air.

In order to carry out effective soil conservation, you must first consider several aspects of the land in question. Here are some of the things that must be considered -

  • Is there enough vegetative cover over the land or does it need to be developed?
  • What are the proper erosion control methods that can be utilized and how will you implement them?
  • What is the soil salinity level and how are you going to manage it?
  • What is the soil acidity level and how are you going to control it?
  • What is the soil mineral content and do you need to regularly add mineral supplements?
  • Is the soil contaminated and, if so, what methods are you going to use to remediate it and to prevent future contamination?
  • Are there beneficial soil organisms in the soil and are they allowed to thrive?

Once you know what kind of soil conservation is needed, you can consider implementing any or all the following methods -

  • Planting dense rows of trees as wind-breaks along the borders of the land, especially on the sides that are exposed to stiff winds. Their roots stabilize the soil and prevent it from being shifted away by the wind.
  • Planting crops in rotation. Alternating crops helps avoid depleting the soil nutrients too fast.
  • Planting cover crops. These stabilize the soil and reduce the effects of soil erosion. They also discourage the spread of weeds and help the soil retain its moisture in the summers.
  • Plowing along the contour of the land.
  • Planting crops parallel to the slope of the land.
  • Going for strip cropping. This involves planting grasses or pulses between regular crops like corn.

    The corn crop is not particularly effective in preventing soil erosion, but the grasses keep erosion in check.

  • Adding mulch to the soil surface. This prevents erosion by acting as a barrier and catching run-off water.
  • Adding coir logs as barriers. These are very useful in areas where too much erosion has taken place and act as erosion preventing barriers and a support for new developing vegetation. Aside from coir barriers, sand bag and gravel bag barriers are also used.
  • Growing grass on slopes and in waterways. Grassed waterways prevent too much soil from being washed away.
  • Making use of natural as well as man-made fertilizers.
  • Keeping the land fallow in order to rest it.
  • Managing the levels of salinity. In areas where irrigation is in excess or where the saline water tables are low, the salinity levels can go up and make the land unsuitable for agriculture. This problem can be resolved by the use of humic acid.
  • Managing the soil pH. The soil pH is what determines the amount of nutrients that the plants can absorb from the soil. Soil pH levels can be raised or decreased, as needed, by adding certain chemicals - for example, agriculture lime for raising pH level and ammonium phosphate for reducing it.
  • Encouraging beneficial soil organisms like earthworms and nitrogen fixing bacteria to thrive in the soil. The presence of such organisms enriches the soil.
  • Using man-made chemical insecticides, pesticides and herbicides in very low amounts. Over use of chemicals can poison the soil and kill of useful organisms, and is generally harmful to the environment.
  • Regularly add minerals to the soil. Minerals provide much-need nutrients to the soil to be absorbed by the plants. To mineralize the soil, add chemical supplements or try adding crushed rock.
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