Nitrogen and Phosphorus Budgets on Claypan Soil Receiving Turkey Litter and Inorganic Fertilizer Applications

Core IdeasNitrogen and P budgets may provide insight regarding fertilization with turkey litter.Total P outputs were greatest with N-based turkey litter application.Nitrogen-based turkey litter application increased soil storage of N and P.Unaccounted-for N was substantial regardless of nutrient source.Only with N-based turkey litter application was there any unaccounted-for P.Nutrient budgets may provide insight for management of N and P in poultry wastes and commercial fertilizers applied to claypan soils. The objective of this study was to calculate budgets for N and P as affected by turkey (Meleagris gallopavo) litter and inorganic fertilizer applications and by incorporation by tillage. The experiment was conducted from 2005 to 2007 near Girard, KS. The soil was a low-slope (1%) Parsons silt loam overlying a claypan B horizon. During the 3-yr budgeting period, total N outputs as surface runoff or as grain removal were not affected by treatments varying in nutrient source or tillage. Total P outputs in surface runoff and as grain removal was greatest in the N-based turkey litter (TL-N) treatment. Nitrogen and P stored in undecomposed grain sorghum [Sorghum bicolor (L.) Moench] stalks were unaffected by treatments. However, the change in soil storage of total N and P was greater in the TL-N treatment compared with the control, the inorganic fertilizer only (Fert), or the turkey litter P-based (TL-P) treatments. Unaccounted-for N in all treatments receiving inorganic fertilizer and/or turkey litter exceeded 170 kg ha(-1) over the 3-yr period. The N that was not accounted for was greater with the TL-N treatment than in the Fert or P-based, incorporated treatment, with the TL-P value being intermediate. The only treatment that showed unaccounted-for P was TL-N. Thus, unaccounted-for N losses may affect all nutrient sources, but unaccounted-for P losses likely only occur when litter application is N based.