Effect of partially covering the turkey litter surface on ammonia emission

A laboratory-scale study was conducted to determine the effect of various percentages of exposed turkey litter surface area on NH3 emission rate using turkey litter obtained from a commercial farm in Iowa. Measurements were conducted in 4 environmentally controlled emission chambers maintained at 21 ± 1°C and a concomitant RH of 50 ± 5%. Four different treatments were investigated, with 0 (control), 25, 50, and 75% of the litter surface area covered with plywood boards that were periodically shifted to different positions to simulate movement of the turkeys in the barn. Concentration of NH3, litter temperature, air temperature, and airflow rate through each chamber were measured continuously over a 6-d experimental period, and measurements were replicated 3 times. The initial placement of the covers on the litter suppressed NH3 emission rate to varying degrees. The covers served as physical barriers to NH3 emission and tended to temporarily reduce and delay the emission but did not affect the 6-d total NH3 emission. Periodic shifting of the covers resulted in the escape of NH3 trapped beneath the covers, resulting in similar overall NH3 emissions among the different treatments. Therefore, based on the results of this study, the increased litter surface coverage by older and heavier turkeys was probably not a cause of lower NH3 emission rates from the turkey barns.