Nitrogen, Phosphorus, and Liming Effects of Layer Manures in Coastal Plain and Piedmont Soils.

Nutrient availability from poultry manures can be affected by soil types and manure processing.  Laboratory and greenhouse experiments were conducted to evaluate N and P availability, and liming value of poultry layer manures (fresh, composted, and pelleted) applied to surface samples of three soil series in North Carolina: Belhaven (Terric Haplosaprists), Cecil (Typic Kanhapludults), and Lynchburg (Aeric Paleaquults). A 90 d incubation compared N mineralization from manures and urea.  Mean availability in the Belhaven and Lynchburg soils was 76, 73, and 55 % of total N applied in fresh, composted, and pelleted manures, respectively; whereas N availability in the Cecil soil was 41, 33, and 27% for the same manure sources.  A 21 d lime incubation found liming materials in all manures just as effective in neutralizing soil acidity as equivalent amounts of CaCO₃.  A 21 d P incubation found similar changes in Mehlich-3 extractable soil P resulting from application of equivalent amounts of either manure or inorganic P.  A greenhouse experiment evaluated millet [Urochloa ramosa (L.) T. Q. Nguyen] response to the three manures on the same soils. Plant available N from the manures followed the decreasing order of fresh > composted > pelleted, similar to the rank order obtained in the N incubation study.  Application of either inorganic or manure P sources to the Belhaven muck resulted in more water soluble soil P and greater plant P uptake than when P was applied to the mineral soils.