Soil Erosion and Our Land
The word "erosion" is derived from the Latin "erosio" which means to "to gnaw away". The local terms of soil erosion imply the physical removal of topsoil due to different agents, which includes water, wind, rain, water flowing over and through the soil profile, ice or gravitational force.
Erosion and Weathering:
Erosion is distinguished from weathering, which is the process of physical or chemical breakdown of the minerals in the soil and rocks, however the two processes are sequential. On-site effects are the breakdown of the soil structure, loss of soil a decrease in organic matter of soil. Erosion may also eliminate available moisture of soil, that results in more drought-prone state. Off-site problems are resulted from sedimentation downwind or downstream that reduces the ability of drainage ditches and rivers, enhance the danger of floods, blockage of canal irrigation and lessens the reservoirs design life. Eroded sediment is a pollutant and the chemicals absorbed by it may alarm the levels of phosphorus and nitrogen in water bodies and eutrophication results.
Types of Soil Erosion:
Wind Erosion: Wind Erosion can be explained as the emimination of soil particles by kinetic energy and force and of the wind. These soil particles are gathered, transported and deposited when the energy of wind falls.
Water Erosion: Water Erosion is caused by the mechanical force of runoff and by the kinetic energy of rain falling on the surface of soil.
Gravity Erosion: Mass movement of soil occurs on steep slopes under gravitational effect.
MAIN CAUSES OF SOIL EROSION
1. CLIMATIC FACTORS
The two most important climatic factors having a direct effect on erosion are precipitation and wind velocity. Other climatic factors have an indirect effect on soil erosion, such as water balance, evapotranspiration, temperature and relative humidity. Indirect factors affect the erosivity of rainfall by altering the soil moisture regime and the proportion of rainfall that may become surface runoff.
2. LAND USE
Humans play a major role in soil erosion through their use and abuse of natural resources, for example deforestation, grazing, arable land use, faulty farming systems, high crop intensity, housing construction, mining etc.
3. SOIL ITSELF
The soil is susceptible to erosion and is influenced by its physical, hydro logical, chemical and mineralogical properties as well as characteristics of soil profile. Important soil physical and hydro logical properties that affect the resistance of a soil to erosion include texture, structure, water retention and transmission characteristics.
4. HYDROLOGY
The important soil erosion components of the hydro-logical cycle are surface detention, infiltration, overland flow velocity and subsurface water flow. The different types of flow and their velocities may be turbulent or laminar, steady or unsteady, uniform or non-uniform and influence the extent of erosion.
5. TOPOGRAPHY
Shape of slope, slope gradient and slope length are the important variables of land form that promote erosion processes for all sorts of erosion, e.g., splash, rill, gully and sheet erosion.
6. SOIL CONSERVATION
Soil is genuinely a non-renewable nature's resource since erosion occurs at that rates which outpace formation of soil. Artificial formation of soil is impractical, therefore we have little choice but to conserve and preserve the soil.
7.TILLAGE
Tillage is the agricultural preparation of soil by ripping, ploughing or turning it. Tillage may also be meant the land which is tilled. There are two sorts of tillage: Primary tillageloosens the soil and blends in plant material and fertilizer resulting in soil with a poor texture. Secondary tillagegenerates finer soil and sometimes shapes the creating symmetries. It can be done by employing different combinations of agricultural equipments: harrow, plough, dibble, hoe, shovel, rotary tillers, subsoiler, ridge or bed forming tillers and roller.
8.WATER HARVESTING
Water Harvesting means storing and capturing rainfall for irrigation of plants and to provide people or animals. This method is one of the oldest gardening methods, dating back to the beginings of agriculture. Water harvesting can help us save money on monthly bills of water and decrease our dependence on water supplied by municipal. A good-designed system also decreases landscape needs of maintenance.