Overgrazing

• Overgrazing occurs when there are too many animals grazing the land than the land has the potential to sustain.
• Farmers stock too many animals such as sheep, cattle or goats on their land. This impacts on soil characteristics.
• Overgrazing  is an increasing problem in The Sahel region of Africa where owning cattle is one of the main criteria for defining wealth in many tribes. This has led herd numbers to increase in recent years
• Overgrazing damages the soil surface and increases the rate of soil erosion.
• Animals eat the vegetation cover and their hooves dig into the soil in wet areas or compact it into a hard surface in dry regions. This prevents grass growth and prevents water from percolating into the soil thus affecting the water content of the soil.
• Water content is a soil characteristic. Soils that are exposed become drier and more easily blown or washed away by wind and rain.
• Dry soils are eroded by the wind very easily.
• Once the soil has been trampled and stripped of plants its structure is damaged and its ability to hold water and nutrients is reduced.
• Soil structure is a characteristic of soil. It is important because plant roots and water are found in the spaces between the soil peds.
• Peds are the small grains which are held together by humus and water.
• Peds have different shapes. Rounded peds give the soil a crumb structure, A crumb structure is best for soil aeration, water content and fertility.
• Overgrazing can change the structure of peds to a platy structure or destroy the structure completely. As a result it can be easily eroded by wind and rain and pasture growth is also reduced. 
• Long periods of drought have caused total rainfall amounts to decline by 30% in the last 10 years.
• A scarcity of water has led to an increase in the number of wells dug to provide for the better watering of animals.
• Herders who used to be nomadic now tend to remain in the one place close to the wells for longer periods.
• Vegetation is lost both in the grazing itself and in being trampled by large numbers of livestock.
• The removal of surface vegetation prevents the creation of humus in the soil thus reducing soil fertility. Humus content is a characteristic of soil. 
• Overgrazing has occurred in Ireland on the Mweelra mountains in Co. Mayo. Farmers were given grants for sheep farming on marginal land by the EU in the 1990’s. This encouraged farmers to overstock their land with too many sheep. The fragile boglands were soon severely eroded.
• Similarly, farmers in the Mezzogiorno in Italy overgrazed their land with large herds of goats leading to soil erosion on the slopes of the Apennines.