Can reclaimer sludge be used to reduce soil acidity?
If preliminary results from a Universityof Wisconsin Soil and Forage Analysis lab study are correct, highly alkaline reclaimer sludge may provide soil nutrients some farmers need. The study, led by John B. Peters, the lab's director, focused on raising the pH of soil planted in alfalfa, a very acid-sensitive crop. "Concrete sludge performed at least as well as conventional aglime in raising the pH levels and increasing the total alfalfa dry material yield in the greenhouse study," says Peters. The pH change occurred relatively soon after application, probably due to the slurry's fineness. When concrete reclaimer sludge was applied at a 0.5 calculated lime rate, soil pH changes were very similar to those for conventional aglime using a 1.0 rate. The Wisconsin Ready Mixed Concrete Association (WRMCA) is currently working with the state's Department of Natural Resources to approve reclaimed slurry as a liming agent. More field studies are anticipated in the spring. For more information about the study, contact WRMCA at 414-529-5077.