A New Method of Poultry Litter Application to Perennial Pasture : Subsurface Banding

1831 Soil Sci. Soc. Am. J. 72:1831-1837 doi:10.2136/sssaj2007.0423 Received 11 Dec. 2007. *Corresponding author ([email protected]). © Soil Science Society of America 677 S. Segoe Rd. Madison WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher. Poultry litter can serve as an invaluable plant nutrient resource for grassland and pasture forage production systems; however, its long-term application to forage production systems can result in adverse environmental impacts associated with surface runoff transport of P to surface water bodies. Considerable research associated with this offsite P transport has been conducted. Losses to surface water runoff of both particulate P and soluble P are of environmental concern. Although litter applications to pastures allow minimal sediment-bound P transport, they do allow accumulation of soluble P at the soil surface, and therefore soluble P concentrations in runoff can become substantial (Sharpley et al., 1994). Periodic tillage of grasslands has been investigated as a management practice to reduce surface runoff transport of soluble P. Sharpley (2003) conducted a laboratory experiment that suggested that mixing surface soils containing high P levels with low-P subsoils through tillage may decrease soil test P (Mehlich 3) in the surface by 66 to 90% depending on the initial soil test P concentrations. Field experiments have since been conducted to demonstrate that periodic moldboard plowing of no-till soils can reduce soil test P (Bray 1) in the surface 2.5 cm by approximately 50 to 85% (Garcia et al., 2007). Rainfall interacts with the surface 1 to 2.5 cm of soil before leaving a fi eld as runoff (Sharpley, 1985); therefore these reductions in near-surface P concentration can result in signifi cant reductions in runoff P losses. In fact, Quincke et al. (2007) reported that a one-time moldboard plow tillage of an otherwise continuous no-till row crop rotation signifi cantly reduced soluble P losses from rainfall simulations conducted 23 and 30 mo after tillage. Inversion tillage, however, is generally not a practical alternative in pasture systems. Additionally, Nichols et al. (1994) found that shallow (2–3 cm) incorporation of surface-applied poultry litter into pasture systems was ineffective at reducing surface runoff P losses. Therefore placement of poultry litter below the soil surface may be an improved alternative to litter incorporation using conventional tillage options. Jason G. Warren* Karamat R. Sistani USDA-ARS Animal Waste Management Research Unit 230 Bennett Ln. Bowling Green, KY 42104