Mineral Nutrition of Cotton Fertilized with Poultry Litter or Ammonium Nitrate

Published in Agron. J. 103:1704–1711 (2011) Posted online 20 Sept 2011 doi:10.2134/agronj2011.0174 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, which is composed of manure and one of several bedding materials, is generated as a byproduct of the chicken (Gallus gallus) or turkey (Meleagris gallopavo) production industry. Poultry litter contains many of the plant nutrients and therefore is land-applied as a fertilizer and as a way of environmentally acceptable waste management. Poultry litter has proven to be an effective fertilizer for agronomic and horticultural crops (Demir et al., 2010; Sistani et al., 2008; Tewolde et al., 2008), forage and pasture crops (McGrath et al., 2010; Sistani et al., 2004), and for forest and other trees (Blazier et al., 2008; Friend et al., 2006). In the southern and southeastern United States, much of the litter generated in the region is applied to forage and pasture fields, but an increasing amount also is applied to row crops, partly because new research in the past 10 yr has shown the benefit of using litter for cotton and other row crop production. In the upland soils of the southern and southeastern United States, research has shown that fertilizing cotton with poultry litter often results in increased lint yield relative to fertilizing with single-nutrient synthetic fertilizers (Endale et al., 2002; Reddy et al., 2007; Tewolde et al., 2008; Tewolde et al., 2009). In an Atwood silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudalfs) in northern Mississippi, broiler litter increased cotton lint yield by 10% under conventional till and by 14% under no-till relative to the standard local fertilization with inorganic fertilizers although litter supplied the same amount of plant available N as the standard local fertilization (Tewolde et al., 2008). In the Black Belt Prairie clay soils of Mississippi, fertilizing cotton with high rates of broiler litter increased cotton lint yield by as much as 26% above that of the local recommendation with conventional fertilizers (Tewolde et al., 2009). On a Decatur silt loam soil (fine, kaolinitic, thermic Rhodic Paleudults) in Alabama, Reddy et al. (2007) found a 5-yr average lint yield increase of about 7% if cotton was fertilized with fresh poultry litter relative to that fertilized with urea. In Georgia on a Cecil sandy loam soil (fine, kaolinitic, thermic Typic Kanhapludults), Endale et al. (2002) showed that no-till cotton yield was better when fertilized with poultry litter than with conventional inorganic fertilizers although the differences were not always significant. This superiority of litter to synthetic fertilizers for cotton production may be related to the ability of litter to supply many of the essential metal and other mineral nutrients in addition to the usual N, P, and K. Whether the better yield performance of cotton fertilized with poultry litter in some soils is due to better mineral nutrition is not well investigated. Further, the mineral nutrient profile of cotton fertilized with broiler litter vs. conventional inorganic fertilizer with rates that range between deficient to sufficient to excess is not well documented. Comparisons of litter-fertilized cotton against cotton fertilized with a selected rate of synthetic fertilizers have been reported. But, while such comparisons are useful, a greater understanding of the contribution of litter-derived mineral nutrients to lint yield may be gained when comparing AbStrACt Poultry litter is a superior fertilizer for cotton (Gossypium hirsutum L.) production in some soils, but whether this superiority is related with its ability to supply multiple mineral nutrients has not been well investigated in the field. The objective of this research was to determine if the yield increasing effect of litter relative to inorganic N fertilizers may be related with better mineral nutrition and to compare the nutrient profile of litterand inorganic N-fertilized cotton. Cotton was fertilized with six broiler litter rates ranging from 2.2 to 13.4 Mg ha–1 or six NH4NO3–N rates ranging from 34 to 168 kg ha –1 plus an unfertilized control (UTC) in northern Mississippi in a silt loam upland soil. Fertilizing with litter resulted in greater concentration of extractable soil P, K, Ca, Mg, Cu, Zn, and Na than fertilizing with NH4NO3, but these increases did not always result in greater concentrations of these elements in aboveground plant parts. Only concentrations of K, B, and Na were increased by litter in plant parts. The two fertilizers had the same effect on soil Mn concentration, but NH4NO3, relative to litter, elevated Mn concentration in plant parts by as much as twofold, a result that seemed to be related to soil pH decline. The results suggest that the better yield performance of fertilizing cotton with poultry litter than with NH4NO3–N in this soil may have been due to a more ideal soil pH, favorable tissue Mn concentration, and improved K and B nutrition.