Effects of Agriculture

In the recent years the human population has grown dramatically. In order to feed the increasing population, many land are used for agriculture and animal grazing. However, people adopt inappropriate agricultural practices. Which causes undesirable effects on the environment, including deforestation, soil erosion, desertification and pollution.

In many developing countries, deforestation occurs to provide land for growing crops. They cultivate by shifting culture and slash-and –burn agriculture. They cut down the trees and pile up and burn the wood. The area left is used for cultivation. After a few years when the lands become infertile, they move and open new land. Deforestation also provides land for grazing livestock. Forests are very important for the well being of our environment. They retain moisture in the air, cool down the air and maintain the balance of carbon dioxide level in the atmosphere. They also lock up nutrients and hold the soil and retain water. Without forests soil erosion, flooding, sedimentation water pollution, global warming, loss of nutrients and reduction in biodiversity.

Inappropriate agricultural practices also have serious harm on the environment. Over-harvesting damages the soil. As crops are harvested, plant tissues together with large quantities of minerals are taken away. Nutrients are depleted from the soil and the land gradually become infertile. Monoculture also occurs when the sane crop is grown over several seasons on the same field. It causes depletion of particular minerals in the soil, which brings about a lot of ecological problems. When pests attack one plant the whole field can be affected. Diseases, specific to a particular crop, can be spread quickly. Chemicals for control of pests will accumulate in soil and will cause water pollution when washed into aquatic bodies. Also, many irrigation water contains various salts, which form a thin crust on the soil surface and accumulate. Salinization causes stunt crop growth and lower yields, which kill plants and ruin soil. It can also accumulate underground and damage the roots of plants.

Soil erosion is the degradation of the topsoil naturally by the wearing actions of rain and wind. One of the major causes is intensive ploughing, especially with the use of inappropriate machinery. It loosens the soil and breaks the soil particles, which stops the soil from absorbing water and humus and soil are loss easily. Over-grazing also lead to soil erosion. If the rate of consumption of the grass by the reared herbivores is faster than the rate of recovery of the land, grass will eventually become too short and will die. Without the grass, soil erosion can easily occur and the soil cannot absorb water and become dry and loose. Soil erosion severely affects the stability, structure and texture of soil. Vital plant nutrients such as nitrogen, phosphorous and potassium are lost. Therefore the fertility decreases and crop production decreases. It also lowers the water-holding capacity of the soil. Crops will not be able to be cultivated anymore and the farmland will need to be abandoned. Soil erosion also pollutes water when the soil is washed away by rain into streams and watercourses. Pesticides and other agricultural chemicals will be carried into aquatic bodies and will contaminate the dish spawning areas and threaten aquatic life.

Desertification is the process by which farmlands are degraded into deserts. It can be caused naturally or by human activities. Natural factors, such as the climate of rainfall, solar radiation and wind will affect the rates of physical and mechanical erosion as well as chemical and biological degradation of soil. The relief of a land also affects the rate of soil erosion by water. The texture, structure and chemical and biological status of soil also determine the soil properties in dry sub-humid zones. Human activities such as uncontrolled use of fire for regenerating pasture, over-exploitation of woody resources, over-grazing of selective vegetation, removal of hedges, over-harvesting, agricultural practices that destroy the soil structure, agricultural practices that continuous removes soil nutrients, monoculture of cash crops and inappropriate irrigation of soil. All of theses factors remove the topsoil that is rich in nutrients leaving the sandy particles with poor water-retaining ability. Therefore the soil becomes unsuitable for vegetation and eventually turned into deserts. Desertification reduces farmlands and threatens the living standard and well being of people inhibiting the areas. It also breaks down the fragile balance that allows plant and animal life to develop in arid, semi-arid and dry sub-humid zones. Which destroys the natural and stable ecosystem.

In order to keep the well being of our environment and to keep our farmlands in good condition and suitable for farming we must have proper approaches during agriculture. We should not over-harvest or over-graze our lands and use inappropriate agricultural methods. Also we should stop deforestation. By doing so, we can keep our farmlands fertile and can have high productivity of crops and can protect our environment, preventing disasters from happening.