Soil conservation

Soil conservation is the preventing of soil loss from [erosion] or reduced fertility caused by over usage,[Soil acidification acidification] [salinization] or other chemical [soil contamination].

[Slash-and-burn] and other unsustainable methods of [subsistence farming] are practiced in some lesser developed areas. A sequel to the deforestation is typically large scale [erosion], loss of soil nutrients and sometimes total [desertification].[File:Mmerosionrazorback.jpg|thumb|right|250px|Erosion barriers on disturbed slope, [Marin County, California] Techniques for improved soil conservation include [crop rotation], [cover crops], [Tillage#Conservation tillage|conservation tillage] and planted [windbreaks] and affect both erosion and fertility. When plants, especially trees, die, they decay and become part of the soil. Code 330 defines standard methods recommended by the US [Natural Resources Conservation Service]. [[File:Contour plowing.jpg|thumb|right|250px|Contour plowing, Pennsylvania 1938. The rows formed slow water run-off during rainstorms to prevent [soil erosion] and allows the water time to [infiltration (hydrology)|infiltrate] into the soil.]Farmers have practiced soil conservation for millennia. Conservation practices fall in multiple categories:

Contour plowing orients crop furrows following the contour lines of the farmed area. Furrows move left and right to maintain a constant altitude, which reduces runoff. Contour plowing was practiced by the ancient Phoenicians, and is effective for slopes between two and ten percent. Contour plowing can increase crop yields from 10 to 50 percent, partially as a result of greater soil retention.

Terracing is the practice of creating nearly level areas in a hillside area. The terraces form a series of steps, each at a higher level than the previous. Terraces are protected from erosion by other soil barriers.

Terraced farming is more common on small farms and in underdeveloped countries, since mechanized equipment is difficult to deploy in this setting. It protects the soil from its erosion. It is one of the way by which soil erosion can be stopped.

Keyline design is an enhancement of contour farming, where the total watershed properties are taken into account in forming the contour lines.jkopk

Tree, shrubs and ground-cover are effective perimeter treatment for soil erosion prevention, by impeding surface flows. A special form of this perimeter or inter-row treatment is the use of a “grass way” that both channels and dissipates runoff through surface friction, impeding surface runoff and encouraging infiltration of the slowed surface water.

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Wikipedia