Using Manure To Mend Mine-Damaged Soils
(USDA Agricultural Research Service) From 1850 to 1950, the Tri-State Mining District of southwestern Missouri, southeastern Kansas, and northeastern Oklahoma produced 50 percent of the zinc and 10 percent of the lead in the United States. The last active mine closed in 1970, but mining’s ecological legacy remains throughout the region—lead-contaminated acidic soils, toxic smelter sites, large quantities of mine tailings called “chat,” and thousands of acres of land with little or no vegetation.
Paul White, a soil scientist in the ARS Sugarcane Research Unit in Houma, Louisiana, was part of a team that studied whether adding beef cattle manure compost to postmining sites would help jump-start revegetation. “Soil microbes recycle nutrients from soil organic matter, and this nutrient cycling is important for vegetation growth. But there is limited soil organic carbon at these sites,” White says. “So we added carbon to the soil via compost to see if that would get these systems going.”
…The researchers amended soils in 3- by 6-foot test plots with either 20 or 120 tons of beef cattle manure compost per acre. No manure was put on control plots. Then they applied switchgrass seed on all of the plots and took soil samples from the plots five times during the 2-year study.
Two years after they amended the plots with the compost, White and his colleagues found that soils in the high-compost plots had significant increases in pH, plant-available phosphorus, total nitrogen, carbon, and available water. High-compost amendments also increased microbial biomass, enzyme activity, and nitrification potential, all of which create and support favorable conditions for plant establishment and growth. READ MORE