Poultry Manure Supply of Potentially Available Nitrogen with Soil Incubation
- Dorivar A. Ruiz Diaz *,
- John E. Sawyer and
- Antonio P. Mallarino
Poultry production is an important and growing livestock industry in Iowa and use of poultry manure as a crop N resource is increasing. Aerobic incubation studies were used to examine potentially available nitrogen (PAN) from poultry manure using two contrasting Iowa agricultural soils, a Clarion loam (fine-loamy, mixed, superactive, mesic Typic Hapludolls) and Canisteo clay loam (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquolls). Two consecutive incubation experiments were conducted, each using the same soils and treatments. Incubation 1 used an approximate rate of 86 mg total N kg−1 incubated for 112 d, and Incubation 2 used an approximate rate of 200 mg total N kg−1 incubated for 84 d. Incubation 2 included more frequent initial sampling. Nitrogen sources included urea, uric acid, and two sources of poultry manure, chicken (Gallus domesticus) and turkey (Melleagris gallopavo) obtained from local production facilities. Soil samples were collected at multiple times during incubation and inorganic NH4 +–N and NO3 −–N concentrations measured. The accumulation of NO3 −–N was used to estimate PAN. The poultry manure sources provided high levels of PAN, 66% of total manure N for chicken and 55% for turkey. These values were lower than those found for urea and uric acid. The majority of the NO3 −–N accumulation occurred within 7 d of incubation, with no increase after 14 d. This indicates that considerable NO3 −–N used to estimate PAN originated from the combined NH4 +–N and uric acid–N components of the poultry manures. However, water soluble nitrogen (WSN) represented approximately 66 and 58% of total N for the chicken and turkey manure, respectively, which are higher than the NH4 +–N plus uric acid–N fractions. These WSN levels are close to the estimated PAN values for each manure source. This indicates that poultry manure analysis for WSN could improve the estimation of crop available–N compared to NH4 +–N or a fraction of total N.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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