Fertilizer Value of Densified Broiler Litter

Abstract

The increase in broiler (Gallus gallus domesticus) production across the southeastern United States and in the state of Alabama has led to locally excessive application rates of broiler litter. Because of the low fertilizer value of broiler litter, there is little economic incentive to transport litter longer distances. Densification of litter could increase the economic transport distance and decrease excessive application in high broiler production areas. Densification could affect litter nutrient concentration and nutrient uptake by forages. The objectives of this research were to determine impacts of litter densification on: 1) litter nutrient concentration, 2) carbon (C) and nitrogen (N) mineralization of densified broiler litter, and, 3) forage yield, nutrient concentration, and nutrient uptake.

Broiler litter was collected from Talladega County, Alabama and densified. Additional moisture added to litter prior to the densification process increased pH and decreased electrical conductivity, copper (Cu) concentration, and iron concentration (Fe). Densification also increased nitrate-nitrogen (NO3-N) concentration, total nitrogen (N), and carbon (C), but decreased concentrations of calcium (Ca), phosphorus (P), and sodium (Na). Soil potential N mineralization was negligible in raw and densified litter treated soils. While changes in nutrient concentrations upon densification were statistically significant, they are not likely to affect the agronomic use of densified litter. Thus, densified litter could be a good alternative to bulky, loose litter when transportation costs are considered. A field study was performed to determine forage yield and nutrient uptake of densified litter, unprocessed litter and commercial fertilizer. Interactions between clover management, cultivar, and year were all found to be significant. Plots with clover had higher plant tissue nutrient concentrations than those without clover. Max Q fescue plots with clover also had significantly higher plant tissue nutrient concentrations than AU Triumph fescue. Overall, densified litter remains a viable substitute for unprocessed litter as differences between the fertilizer types were extremely small and are not likely to affect agronomic use of densified litter. Increased litter density could enlarge the economic hauling radius of broiler litter, though more research is needed to determine cost benefits of the densification process.