Title: Mechanical termination of diverse cover crop mixtures for improved weed suppression in organic cropping systems

Abstract: Cover crops can provide many benefits in agroecosystems, including the opportunity for improved weed control. However, the weed suppressive potential of cover crops may depend on the species (or mixture of species) chosen, and the method of cover crop termination and residue management. The objective of this study was to determine the effects of cover crop mixture and mechanical termination method on weed biomass and density, and relative crop yield in an organic cropping system. A field experiment was conducted from 2009 through 2011 near Mead, NE, USA where spring-sown mixtures of 2, 4, 6, and 8 cover crop species were included in a sunflower - soybean - corn crop rotation. Cover crops were planted in late-March, terminated in late-May using a field disk or sweep plow undercutter and main crops were planted within one week of termination. Terminating cover crops with the undercutter consistently reduced early-season grass weed biomass, whereas termination with the field disk typically stimulated grass weed biomass relative to a no cover crop control (NC). The effects of cover crop mixture were not evident in 2009, but the combination of the undercutter and the 8-species mixture reduced early-season weed biomass by 48% relative to the NC treatment in 2010. Cover crops provided less weed control in 2011, where only the combination of the undercutter and the 2-species mixture reduced weed biomass (by 31%) relative to the NC treatment. Termination with the undercutter resulted in relative yield increases of 16.6 and 22.7% in corn and soybean, respectively. In contrast, termination with the field disk resulted in a relative yield reduction of 13.6% in soybean. The dominant influence of termination method highlights the importance of appropriate cover crop residue management in maximizing potential agronomic benefits associated with cover crops. [Sam Wortman, Charles Francis, Mark Bernards, Erin Blankenship & John Lindquist (2012). Mechanical termination of diverse cover crop mixtures for improved weed suppression in organic cropping systems. Weed Science, online 01 Aug 2012. dx.doi.org/10.1614/WS-D-12-00066.1] ${imageDescription} Comment

Keywords: organic farming, allelopathy, mechanical weed control, ecological weed management, physical weed suppression, biodiversity

Original source




Article: WeedsNews3611 (permalink)
Categories: :WeedsNews:organic farming, :WeedsNews:research alert, :WeedsNews:tillage, :WeedsNews:allelopathy, :WeedsNews:non-chemical control
Date: 9 August 2012; 12:06:23 AM AEST

Author Name: David Low
Author ID: adminDavid