Total and Water Soluble Nutrient Contents of Poultry Litter from Arkansas.

The nutrient content of poultry litter should be measured to determine its fertilizer value for nutrient management planning.  Our objectives were to i) characterize the chemical properties of various poultry litter forms and ii) evaluate the relationship between water-extractable P (WEP) determined using two water-extraction methods.  Poultry litter samples (n=621) submitted from 2005-2007 from the Eucha/Spavinaw watershed in northwest Arkansas and northeast Oklahoma were analyzed at the University of Arkansas Agricultural Diagnostic Laboratory in Fayetteville for moisture, total P, WEP (10:1 water:moist manure), pH, and total N, NH₄-N, NO₃-N, P, K, Ca, and C.  Litter samples included broiler (297), pullet (53), hen (121), turkey (26), and unidentified sources (124).  In 2006, selected litter samples (n=226) were also analyzed for WEP via ICPS using the 10:1 (moist basis) and 100:1 (dry basis) methods.  Selected chemical property means of broiler litter, the most common litter form, were 31 g N kg^-1, 15 g P kg^-1, 972 mg WEP kg^-1 (10:1), 25 g K kg^-1, 25 g Ca kg^-1, 253 g C kg^-1, 8.4 pH, and 308 g H₂O kg^-1.  The comparison of WEP methods showed WEP was linearly (P<0.0001, r² = 0.41) related with the 100:1 method and extracted greater amounts of P (mg WEP 100:1 kg^-1 = 2.16x + 1799, where x = WEP 10:1) than the 10:1 method.  Although total P was positively correlated (r=0.31) with WEP (100:1), the correlation was relatively weak.  Samples analyzed for WEP in 2006 contained a wide range of total P (5.7-23.9 g kg^-1), percent solids (33.7-91.2%) and WEP (100:1, 1371-6527 mg kg^-1), which highlight the need for routine manure analysis when these values are used in P indices to assess the risk of P runoff.