(2000), among the four soils tested herein, those strictly classified as erodible
materials, according to their respective percentage of fines, plasticity index and Pi [s.sup.-1] ratio, correspond to PRS, YRS and WRS soils, confirming previous assessments that pointed out the RRS soil as the one with lower erosive potential.
These areas have highly erodible
soil consisting of loam, silt loam and sandy loam.
The route included in the SER crosses fewer miles of threatened and endangered species habitat, fewer streams and rivers and considerably fewer miles of severely wind erodible
In expanding these estimates to cover the world, it is assumed that roughly 10% of the world's cropland is highly erodible
, as in the United States, and should be planted in grass or trees before the topsoil is lost and it becomes barren land.
In the U.S., where farmers were required to implement a soil conservation plan on erodible
cropland to be eligible for commodity price supports, the no-till area went from 7,000,000 hectares in 1990 to 25,000,000 in 2004.
Payment was made to limit production of specific commodities, but there was no requirement that the land be erodible
. Consequently, enrollment occurred on the least productive land and intensification of production occurred on other land, which increased degradation.
If soils have an El greater than 8, they are considered highly erodible
and the producer needs to seriously consider their suitability for cultivation.
The reductions in areas under these crops have occurred because of a combination of competition for land from products with rising demand, such as fruit and vegetables; land degradation from overexploitation; government programs to divert erodible
land to pastures and tree crops; and displacement of land through urbanization and infrastructure development.
farmers systematically retired roughly 10 percent of the most erodible
cropland, planting the bulk of it to grass, according to the USDA.
For those who may not be up to speed on CRP, it's a federal program begun in 1985 to compensate farmers willing to set aside--as in not farm--their highly erodible
cropland for 10- or 15-year periods.
Participating landowners agree not to convert their land to non-agricultural uses and to develop and implement a conservation plan for any highly erodible
Much improvement is attributed to removal of over thirty-six million acres of erodible
land from cultivation, entered into the Conservation Reserve Program begun in 1985.