Cotton Lint Yield Improvement Attributed to Residual Effect of Repeated Poultry Litter Application

Published in Agron. J. 103:107–112 (2011) Published online 11 Nov 2010 doi:10.2134/agronj2010.0274 Copyright © 2011 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. 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. P litter is a bulky mix of mainly chicken (Gallus gallus) manure and bedding materials. It is generated in large quantities on a continuous basis in major poultry producing areas of the United States. Th is constant litter supply is managed by repeated land application to fertilize crops as an alternative to chemical fertilizers. Poultry litter as a fertilizer has been shown to be as eff ective as or superior to conventional inorganic fertilizers for row crops (Endale et al., 2008; Mitchell and Tu, 2005; Tewolde et al., 2007b) as well as forage and pasture crops (Evers, 1998; Lucero et al., 1995). However, repeated annual applications of litter to the same soil may have long-term crop production and environmental consequences (Kingery et al., 1994) which are not well understood. Unlike many conventional fertilizers, poultry litter and other manures persist in the soil beyond the fi rst season of application. Conventional N fertilizers in general are water soluble and much of the N is either used by the target crop or lost to leaching or volatilization in the fi rst season, particularly in wet environments. Conventional P and K fertilizers are also as water soluble as but more persistent than N fertilizers. Not all components of poultry litter and manures are soluble in the soil solution, implying that the insoluble materials persist in the soil and aff ect crop productivity in subsequent years following the mineralization of nutrients. Th e persistence of manures in the soil longer than the same season of application is well documented for cattle (Bos taurus) manure (Eghball et al., 2004; Hao et al., 2008; Indraratne et al., 2009; Mugwira, 1979; Wallingford et al., 1975), swine (Sus scrofa) manure (McAndrews et al., 2006), and to some extent poultry litter (Kingery et al., 1994; Mitchell and Tu, 2005; Nyakatawa et al., 2001; Reddy et al., 2009). Despite the common knowledge that manures applied in 1 yr aff ect crop growth and productivity in subsequent years, the magnitude of this carryover eff ect has not been adequately studied. Additionally, whether the rate of manure applied to soils that have a short history of manure application can be reduced is not well known. Th e objective of this research was to determine and quantify the contribution of any carryover eff ect of moderate rates of poultry litter to cotton lint yield in subsequent years.