Sowing Method Effects on Clover Establishment into Permanent Pasture

Published in Agron. J. 104:1217–1222 (2012) Posted online 15 June 2012 doi:10.2134/agronj2012.0035 Copyright © 2012 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. E clover (Trifolium spp.) into permanent pasture can be challenging, because many factors like competition from existing the sward, subsequent grazing management, or weather fl uctuations can aff ect this process. Two common overseeding methods for clover include surface sowing without disturbance (broadcasting) or drilling of seed through undisturbed sod and residue (Pearson and Ison, 1997). Frost-seeding is a form of overseeding when seed is broadcasted mid-winter on top of snow and frozen ground or in early spring aft er snowmelt (Casler et al., 1999). Once sown, the freezing and thawing of the ground helps to incorporate seed into the soil. Th is allows for better seed-to-soil contact and reduces the equipment required for planting (Kankanen et al., 2001). Both no-till drilling and broadcasting have strengths and weaknesses. Th e advantage of no-till drilling is more control over seeding depth to ensure good seed-to-soil contact (Campbell, 1985a). A disadvantage of no-till drilling is that use can be limited by steep topography. Broadcasting requires less machinery and is virtually unrestrained by topography. However, no-till drilling is considered superior to broadcasting, because more control helps ensure a proper seeding depth (Taylor et al., 1972). Several experiments that have compared broadcasting with no-till drilling found varying results. Taylor et al. (1969) discovered that drilling clover seed was important for successful establishment of red clover (Trifolium pratense L.). Th ey found that extreme moisture and temperature fl uctuations on the surface of the soil caused low establishment of broadcasted seed. Cuomo et al. (2001) found no diff erence between drilling and broadcasting in establishment across several forage legumes. Th ey learned that the main factor that determined legume establishment was the suppression of grass species. Byers and Templeton (1988) discovered that drilling produced more alfalfa (Medicago sativa L.) biomass over broadcasting, and Mueller and Chamblee (1984) found that broadcasting was more eff ective when sowing was done in late winter than in spring. In their experiment, white clover broadcasted in mid-February had greater establishment than when broadcasted in mid-March. When averaged between the two sowing dates, however, white clover (Trifolium repens L.) establishment was greater in the drilled treatments. Although sowing method should have a major impact on clover establishment, relatively few studies have compared broadcasting (frost-seeding) to no-till drilling. More information is needed about clover overseeding methods to provide guidelines to help improve establishment success. To add to this body of research, a pasture experiment was conducted from 2009 to 2011 near Blacksburg, VA. Th e primary objective of this study was to compare the eff ectiveness of broadcasting (frost-seeding) and no-till drilling for establishment of white and red clover. A secondary objective was to identify potential management variables that may help explain the success or failure of seeding methods.