IL S Water Treatment Residuals and Biosolids Long - Term Co - Applications Effects to Semi - Arid Grassland Soils and Vegetation

SSSAJ: Volume 73: Number 6 • November–December 2009 Soil Sci. Soc. Am. J. 73:1880-1889 doi:10.2136/sssaj2008.0352 Received 31 Oct. 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. W treatment residuals and biosolids are both byproducts from municipal treatment processes. Aluminum-based WTR are considered a waste product from drinking water treatment facilities. Alum [Al2(SO4)3 · 14H2O] is the main component in the water purifi cation treatment process used to destabilize and fl occulate colloids, creating WTR. Biosolids are a byproduct of wastewater treatment. Both byproducts have been studied separately for their eff ects and benefi ts for land application. Because WTR have the propensity to strongly adsorb P (Ippolito et al., 2003; Makris et al., 2004), land co-application may be advantageous to municipalities as a means of reusing high P-bearing biosolids in an environmentally sound manner (Ippolito et al., 1999). However, soil co-application studies of WTR and biosolids are limited. Harris-Pierce et al. (1993) studied the short-term eff ects of WTR-biosolids co-application on soils and aboveground plant biomass of four shortgrass prairie species. Aboveground biomass and canopy cover of individual plant species were not aff ected by increasing WTR rate (5, 10, and 21 Mg ha–1) co-applied with a single biosolids rate (10 Mg ha–1). Th e authors noted a decrease in fringed sage (Artemesia fr igida) and blue grama (Bouteloua gracilis) P and Mo plant tissue content with increasing WTR rate. HarrisPierce et al. (1993) also noted little change in soil elemental content with soil depth associated with increasing co-applications. In a follow-up study, Ippolito et al. (2002) examined the effects of diff erent combinations of WTR and biosolids on western wheatgrass (Pascopyrum smithii [Rydb.] A. Love) and blue grama and showed that WTR reduced plant-available P to both species. No visual P defi ciencies were observed, and the authors suggested that co-application can aid municipalities dealing with excessive biosolids-borne P. Ippolito and Barbarick (2006) added WTR to a high P-bearing biosolids-amended soil, which resulted in signifi cant P decreases with increasing WTR rates. Although these studies support the concept of WTR benefi cial reuse concomitant with biosolids usage, the long-term benefi ts of the WTR-biosolids co-applications were not researched. Agyin-Birikorang et al. (2007) added WTR to heavily manured soils, noting that Al-based WTR immobilized P and remained stable 7.5 yr following initial land application. In a similar J. A. Ippolito* USDA-ARS-NWISRL 3793 North 3600 East Kimberly, ID 83341-5076