User:Skyevergreen/sandbox

Soil loss tolerance for a specific soil, also known as the T value, is the maximum average annual soil loss expressed as tons per acre per year that will permit current production levels to be maintained economically and indefinitely. T values range from 1 to 5 tons per acre per year. According to the United States Department of Agriculture's National Resource Conservation Service, in 2007 in the US, 99 million acres (28% of all cropland) were eroding above soil loss tolerance (T) rates. This was compared to 169 million acres (40% of cropland) in 1982. A commonly used equation to calculate the T value is: