THE EARTH’S RESOURCES AND POLLUTION

Soil Degradation Scientist’ studies and the experiences of farmers have shown that the most productive soil, or the type of soil most plants grow best in, is loan with a neutral pH that is workable, contains nutrients and holds water. Human activity can cause erosion, desertification and pollution and makes soil less productive. The deterioration of the soil characteristics needed for plant growth or other ecosystem services is called soil degradation. Soil degradation results in major ecosystem changes, It can also make faring more challenging, so it could make it more difficult to feed Earth’s growing human population in the future.

Erosion o Erosion and deposition are natural processes that, in the long run, can help create soil o Erosion can be a problem because it occurs more quickly than soil is formed. o Erosion tends to remove the fertile topsoil layer. o Human activity cause more erosion than natural events. Humans make soil more vulnerable to erosion by leaving soil bare after harvest, overgrazing rangelands and clearing forests on steep slopes or with large clear-cuts

Causes of Erosion Farming Practices – Plant communities, including crops, protect soil from erosion. Plants slow wind and water and their roots hold soil in place. After fields are harvested, and there is no plant cover protecting the soil, wind and eater can erode the soil, especially if the land is sloped Ranching Practices – AS long as livestock populations stay within a range’s carrying capacity and do not eat grasses faster than the grasses grow back, grazing may be sustainable. However, when to many animals eat to much of the plant cover, impeding regrowth the result is overgrazing. Effects of overgrazing – some of the problems of overgrazing rise to a positive feedback loop that increases damage to sols, natural communities and the land’s productivity Forestry Practices – Some current methods, such as clear cutting, can lead to severe erosion.

Desertification o Desertification is a loss of more the 10 percent of productivity due to erosion, soil compaction, forest removal, overgrazing, drought, salt buildup, climate change, depletion of water resources ad other factors o Severe desertification can enlarge existing deserts and create new ones in once-fertile regions

Soil Pollution o Irrigation: the process of providing water other then precipitation to crops o Salinization: The build up of salts in the upper horizons. In dry areas where precipitation in minimal and evaporation rates are high, water evaporating from soil’s A horizon may pull water up from lower horizons as water rises through the soil it carries dissolved salts. Irrigation water also usually contains some dissolves salts, so it adds salt to the soil, increasing salinization. o Pesticides: Toxic pesticides can and the chemicals they break down into may remain in soil for long periods of time, basically poisoning it. Although pesticide may increase the amount of a crop produced n a given area in the short term they can be hazardous to humans and other animals in the long term