Soil erosion
Soil quality is one of the most basic and perhaps least understood indicators of land health. Soil supports plant growth and represents the living reservoir that buffers the flows of water, nutrients, and energy through an ecosystem. The ongoing degradation of the earth's soils by human activity, particularly agriculture, threatens human potential to feed a growing population. The annual global erosion amounts to about 36 billion tons, of which 10 billion are due to natural causes and 26 billion are the result of human activity (Crosson et al. 1995). The soil or runoff that has been eroded ends up in groundwater, lakes, streams, and rivers. The deposits of excess soil and the contaminates in it, cause further ecological complications. Bodies of water need to be dredged and monitored for contamination. Water levels are lowered with the increasing soil eroded into them, making our world's water supply a concern directly related to the erosion of soil. The process of soil renewing itself is largely unknown. However, there is consensus on the need for conservation. Evaluating the scope of the problem or predicting the effects that various solutions might have on agriculture and the environment is very difficult. Degradati
The Department of Agriculture (Elliott et al. 1987) certifies organic production systems. Certification involves the development of an organic plan for the operation, the plan to be evaluated and approved by an accredited agent, and the agreement of the farmer to abide by the list of approved substances. The organic agent also reviews soil and water tests, crop histories, production, and rotation plans. The area in which organic crops are to be grown must be chemical free for 3 years. They verify compliance with standards through annual and spot inspections, and record keeping requirements (Elliott et al. 1987). Many conservation efforts are being taken to control soil erosion. In order to do this a universal language is need to measure soil erosion, texture, and the potential for erosion. Soil loss tolerance ("T") is the amount of a given soil that can be displaced by water or wind erosion each year and be replenished through natural soil regeneration processes. This is a basis for evaluating the impacts of soil erosion and develops objectives for conservation treatment. Erosion at rates greater than T is a special concern because it threatens agricultural sustainability. Gachene, N.J. Jarvis, H. Linner, J.P. Mbuvi. 1997. Soil erosion effects on soil properties in a highland area of central Kenya. Soil Science Society of America Journal v61 n2 p559. Native Americans have used good agriculture practices for years. American Indians had respect for the land and all of its life forms. One of their cultural beliefs about farming is centered on the three sisters: corn, squash, and beans. The corn provides a stalk for beans to climb. Beans produce nitrogen that fertilizes the corn. And squash protects the soil and corn roots from the sun, traps moisture, and prevents erosion. All three plants provide edible food, while preserving soil. (Wilken 1995) Data from erosion plots in Tarija suggest only moderate rates of erosion (200tons-per. yr.). Data at 6-min intervals for 41 sites in the tropics of Australia were used to compute the rainfall and runoff factor (R-factor) for the Universal Soil Loss Equation (USLE), and a daily rainfall erosivity model was validated for these tropical sites. Mean annual rainfall varies from about 300 mm at Jervois to about 4000 at Tully. For these tropical sites, both rainfall and rainfall erosivity are highly seasonal. The daily erosivity model performed better for the tropical sites with a marked wet season in summer in comparison to model performance in temperate regions of Australia where peak rainfall and peak rainfall erosivity may occur in different seasons (Yu 1998).
Some common words found in the essay are:
Agriculture Elliott, , Wind Erosion, World Report, Equation USLE, American Indians, Costa Rican, Resosudarmo1995 Agricultural, Na Na, Ghidey Alberts, soil erosion, soil loss, et al, soil quality, et al 1998, wind erosion, al 1998, soil water, rainfall erosivity, baffaut et, runoff soil, baffaut et al, soil science society, et al 1987, society america journal,
Approximate Word count = 2964
Approximate Pages = 12 (250 words per page double spaced)
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