Soil and Water Quality Rapidly Responds to the Perennial Grain Kernza Wheatgrass

Published in Agron. J. 105:735–744 (2013) doi:10.2134/agronj2012.0273 Copyright © 2013 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. A major goal of current agronomic research is to make annual grain crop production more sustainable, with management strategies that supply adequate fertility to meet crop demand while conserving soil and water quality. For temperate humid environments, these management strategies typically strive to minimize soil disturbance (e.g., no-till and conservation tillage strategies), maximize plant cover on the soil (e.g., cover crops and no-till), and manipulate fertilizer strategies and sources to reduce nutrient losses to the environment (e.g., organic amendments and precision agriculture) (Robertson, 1997; Raun and Johnson, 1999; Snapp et al., 2005, 2010; Grandy et al., 2006). The management choices that growers make can have dramatic impacts on local ecosystem services. For example, N fertilizer type, rate, and application in relationship to crop demand are important regulators of N cycling efficiency and loss pathways; this has direct and indirect consequences for water and soil quality (Robertson, 1997; Snapp et al., 2010; Syswerda et al., 2012). Despite the realized environmental benefits of some conservation management strategies, grower adoption of these strategies can be limited for a variety of socioeconomic and biophysical reasons (Snapp et al., 2005; Grandy et al., 2006). Another approach that has received far less attention than management strategies for improving ecosystem services is to “perennialize” annual grain systems via breeding for new perennial grain crops (Glover et al., 2010b). The perceived benefits of this approach are based on inferences from agronomic research that has consistently shown herbaceous perennial systems, such as forages or restored or native grasslands, outperforming annual cropping systems with regard to soil conservation (Montgomery, 2007), primary production and C cycling efficiencies (Buyanovsky et al., 1987; Jenkinson et al., 1994; Silvertown et al., 1994; Glover et al., 2010a; Zeri et al., 2011), N cycling efficiencies (Jenkinson et al., 2004; Glover et al., 2010a; Syswerda et al., 2012), maintenance of soil nutrient stocks and soil C pools (Buyanovsky et al., 1987; Jenkinson et al., 2004; Mikhailova et al., 2000; Culman et al., 2010; Bremer et al., 2011), and maintenance of soil food webs (Ferris et al., 2001; Culman et al., 2010; DuPont et al., 2010). These benefits have been documented in established herbaceous perennial systems, but future perennial grain systems will likely be rotated with other crops and will have to be reestablished with each rotation. The length of time newly planted perennial crops need to improve ecosystem services is very important because there have been some reports of decreased ecosystem services in establishing herbaceous perennials (McLaughlin et al., 2002; Syswerda et al., 2012). One promising perennial grain crop is intermediate wheatgrass, a widely adapted, high-yielding, cool-season forage grass that provides excellent feed for livestock in the Great Plains ABSTRACT