TY - JOUR T1 - Long-term impact of broiler litter on chemical properties of a Coastal Plain soil JF - Journal of Soil and Water Conservation SP - 65 LP - 74 VL - 61 IS - 2 AU - G.J. Gascho AU - R.K. Hubbard Y1 - 2006/03/01 UR - http://www.jswconline.org/content/61/2/65.abstract N2 - Broiler chicken (Gallus gallus) production is increasing rapidly in the southern Coastal Plain where there is an abundance of agricultural crops. The litter (mainly manure and bedding material) is a proven source of crop nutrients. We measured the pH, carbon (C), and extractable nutrient elements to a depth of 90 cm (3 ft) prior to and following seven years of an irrigated conservation-tilled double-cropped rotation. Litter was surface-applied to each crop at four rates (0, 4.5, 9.0, and 13.5 Mg ha−1 yr−1; 0, 2, 4, and 6 t−1 ac−1 yr−1) during the first five years of the rotation. Concentrations of extractable nutrient elements from the applied litter remained below levels of environmental concern during this seven-year study. Several trends in the data suggest that there will likely be problems with longer-term applications at high rates in the intensive crop rotation. Increases of extractable phosphorus (P), zinc (Zn), and copper (Cu) (contained in broiler feed) are of greatest concern. Phosphorus, extracted by Mehlich-1, increased >100 mg kg−1 (>100 ppm) in the surface soil due to the greatest BL rate. Many crops will thrive when soil P is high, but depending on slope and other soil properties, potential exists for losses of P via surface runoff or leaching. Such losses have been correlated with extractable P. Potassium from litter appeared to move to depths beyond the rooting zone of some crops. Concentrations of Cu increased four-fold and Zn five-fold in the top soil at the greatest rate of litter. Continuance of the applications at high rates will eventually lead to toxicity, particularly Zn toxicity in peanut (Arachis hypogaea L.). Nitrate-nitrogen concentration remained low through the soil profile. Potential benefits from broiler litter were attained by the maintenance of pH and an increase of 2.7 Mg C ha−1 (1.2 t C ac−1) in the top 15 cm (6 in). Results of the study suggest that litter can be utilized well, without negative environmental effects when it is applied at conservative rates. ER -