A Essay On Soil Erosion With Key Words
Answers
Answer:
Soil erosion is defined as the detachment and transportation of soil mass from one place to another through the action of wind, water in motion or by the beating action of rain drops. Erosion extensively occurs in poorly aggregated soils (low humus) and in a higher percentage of silt and very fine sand. Erosion increases when soil remains bare or without vegetation.
Soil erosion occurs when the rate of removal of soil by water/and wind exceeds the rate of soil formation. Generally, rates of soil formation are very low, with profiles developing at a rate of about 1 cm every 100-400 years.
It is important to differentiate between natural or backward erosion and erosion which has been accelerated largely as a result of human activity. Background erosion rates are often similar to rates of soil formation although in mountainous areas they may be considerably higher.
Some of the highest soil erosion rates have been observed in the less plateau areas of China and in the Himalayan foothills of Nepal. In India gully erosion results in a loss of about 8000ha of land per year.
Materials can be lost from soils in four main forms – gases, solutes, particulate material and vegetation removal. As in the case of additions, the processes involved can usefully be divided into surface and subsurface categories.
Surface losses include gases which are produced during organic matter decomposition and lost to the atmosphere, solutes which are taken up as nutrients by vegetation and then lost when the vegetation is removed, for example by harvesting of crops or removal of trees, particulate material which is lost by water or wind erosion, and the upper parts of profiles which may be removed by erosion or human activity.
In the case of gases and solutes, the significance of losses via the surface will depend on the extent to which they are dissolved and lost by subsurface drainage; which in turn will depend on climate and land use.
Removal of particulate material by wind will be most effective in the case of soils with a high silt or fine sand content, as this size of maternal is more easily entrained than larger, heavier particles or small clay particles which resist entrainment due to their greater aggregation.
Organic matter is also prone to wind erosion, and its lower density relative to mineral material means that larger particles can more easily be carried. Low moisture content, poor aggregation and sparse vegetation covers will also enhance susceptibility to erosion. Small particles (< 0.05mm in diameter) are transported by aerial dispersion and may be carried to elevations of several thousand metres.
Particles of intermediate size (0.05 – 0.5 mm) are transported within a metre or so of the ground surface by the process of saltation. In contrast, large particles (> 0.5 mm) are moved along the ground, largely as a result of impacts from saltating particles, by the process of creep.
Hope it helps you
follow me and Mark it as brainliest