GARDENS - Studies show biosolids can boost soil phosphorus levels for years

Treated wastewater solids called biosolids are sometimes used by farmers to boost soil nutrient levels. Now research by a U.S. Department of Agriculture (USDA) scientist provides new information about how long those plant nutrients remain after biosolids have been applied to the soil.

http://phys.org/news/2013-01-biosolids-boost-soil-phosphorus-years.htm