N Cotton Response to Poultry Litter Applied by Subsurface Banding Relative to Surface Broadcasting

SSSAJ: Volume 73: Number 2 • March–April 2009 Soil Sci. Soc. Am. J. 73:384-389 doi:10.2136/sssaj2008.0127 Received 14 Apr. 2008. *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 is a mixture of chicken manure and bedding material. Land application as a fertilizer is the most common and accepted method of managing litter. Typically, it is applied on the soil surface by means of broadcasting and may or may not be incorporated by mixing it with the surface soil layer. Broadcast application, regardless of the incorporation, exposes certain litter nutrients to volatilization loss. The most important of these nutrients is N, part of which is lost as NH3 during or after application (Sharpe et al., 2004; Webb et al., 2005). Volatilization loss occurs at all stages of litter handling, from the time of its generation in the poultry house until its deposition on land and covering by the soil. Once the litter is removed from the house, the greatest volatilization loss occurs at the time of land application with traditional manure spreaders. Several types of spreaders are available, most of which spread the litter by scattering the litter along, and laterally out from, the path of the spreader. This process separates litter particles and exposes volatile litter compounds to the air, depending on the moisture content and particle size of the litter. This exposure allows NH3 and other compounds to volatilize from the litter particle surfaces. Additionally, once applied, separated litter particles remain on the soil surface, further exposing the litter to volatilization. In addition to diminishing the litter’s fertilizer value, loss of NH3 is an important air pollution and greenhouse gas issue (Webb et al., 2005). Loss of NH3 and other volatile compounds from litter can be reduced by incorporating the litter into the soil, especially if this can be accomplished within a few hours of spreading (Webb et al., 2005). While incorporation is effective in conserving N, the greatest loss may actually take place during surface broadcast application and before incorporation. Eliminating or minimizing litter exposure to the air by eliminating the spreading process, as in broadcast application, should eliminate or reduce the volatilization loss of nutrients and organic comHaile Tewolde* USDA-ARS Genetics and Precision Agriculture Research Unit 810 Highway 12 East Mississippi State, MS 39762