Submitted to: World Congress of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/30/2018
Publication Date: N/A
Technical Abstract: Recurrent land application of broiler litter in regions with a high concentration of poultry farms result in soils with phosphorus (P) far beyond the agronomic requirement of crops. A new waste treatment technology developed by USDA-ARS, called “Quick Wash”, chemically extracts and recovers P from broiler litter while leaving most of the nitrogen (N) and carbon (C) in the low-P treated litter. The low-P treated litter can then be safely land applied at agronomic N rates. A laboratory test was performed to evaluate the N mineralization and nitrous oxide (N2O) emissions in a Norfolk soil (Fine-loamy, kaolinitic, thermic Typic Kandiudults) amended with low-P litter. Two sets of undisturbed soil cores (0.15 meter x 0.05 meter diameter) received the following treatments applied onto the soil surface in triplicate: un-amended soil (control), untreated litter, pelletized untreated litter, loose low-P litter, and pelletized low-P litter. All cores were adjusted to 60 % water-filled porosity and incubated at 25°C for 68 days. Soil from one set of cores was sampled on a weekly basis. Soil samples were extracted with 2 molar potassium chloride and analyzed for ammonium (NH4) and nitrate (NO3) to estimate the net N mineralization (Nm) rate of each poultry litter amendment. Another set of cores were enclosed in plastic jars having a gas sampling port for periodic N2O emission measurements by gas chromatography. The Nm rates were in the range of 4.0 to 5.7 miligrams per kilogram of soil per day (mg/kg soil/day) for untreated litter, pelletized untreated litter, and loose low-P litter while pelletized low P-litter and the unamended soil control were significantly lower, in the range of 1.7 to 2.0 mg/kg soil/day. The cumulative N2O production from the pelletized raw, loose raw, loose low-P, pelletized low-P litter, and un-amended soil were 1261, 894, 407, 287, and 80 micrograms of N2O-N per kg of soil, respectively. Therefore, percent of N2O losses from the total applied N were 1.4%, 1.0%, 0.5%, and 0.3% for pelletized untreated litter, untreated litter, loose low-P litter, and pelletized low-P litter, respectively. Since the treated pelletized low-P litter also had the lowest nitrification rates, it appears as an efficient solution to conserve N and mitigate losses by N2O emissions or NO3 leaching after soil application.