Effect of Pond Ash on Pen Surface Properties

The maintenance of feedlot pen surfaces, which includes removal of manure and replacement of fill soil, is a time-consuming and expensive process. Pond ash (PA), a by-product of coal-fired electrical generation, has been proposed as a feedlot pen surface amendment because of its foundational support characteristics. A study was conducted to compare the performance of PA-surfaced pens to traditional soil-surfaced (SS) pens. Four of eight SS pens (7.3 m × 20.7 m) were excavated to a depth of 0.5 m and resurfaced with PA. The remaining four pens were kept as SS. Eight heifers were housed in each pen (19 m head) for four feeding cycles that ranged from 73 to 172 days. Following each feeding cycle, the animals were removed and the pens were cleaned. A subsample of the accumulated manure was removed from each pen for analysis of total mass (TM), total solids (TS), volatile solids (VS), percent volatile solids (VS%), moisture, and ash content. Higher heating value (HHV) was estimated using the VS% and moisture content. As compared to the SS pens, surfacing pens with PA reduced TM by 34%, TS by 34%, and ash content by 46%. PA increased VS% by 70% and HHV by 75%. Restoring the PA-surfaced pens to the original grade required only 25% of the amount of fill material required for the SS pens. However, there were no differences in the total amount of VS removed. Harvested feedlot surface material (FSM) from the PA pens was more nutrient and energy dense, based on the increased VS% of the collected material. The increased density improved the economics of transport and handling, and allowed for greater energy recovery. In addition, the PA pens were less erodible than the SS pens.