Allelopathic cover crop prior to seeding is more important than subsequent grazing/mowing in grassland establishment

Rangeland Ecology and Management
By: , and 

Links

Abstract

The effects of grazing, mowing, and type of cover crop were evaluated in a previous winter wheat–fallow cropland seeded to grassland under the Conservation Reserve Program in eastern Colorado. Prior to seeding, the fallow strips were planted to forage sorghum or wheat in alternating strips (cover crops), with no grazing, moderate to heavy grazing, and mowing (grazing treatments) superimposed 4 yr after planting and studied for 3 yr. Plots previously in wheat had more annual and exotic species than sorghum plots. Concomitantly, there were much greater abundances of perennial native grass and all native species in sorghum than wheat cropped areas. The competitive advantage gained by seeded species in sorghum plots resulted in large increases in rhizomatous western wheatgrass. Sorghum is known to be allelopathic and is used in crop agriculture rotations to suppress weeds and increase crop yields, consistent with the responses of weed and desired native species in this study. Grazing treatment had relatively minor effects on basal and canopy cover composition of annual or exotic species versus perennial native grass or native species. Although grazing treatment never was a significant main effect, it occasionally modified cover crop or year effects. Opportunistic grazing reduced exotic cheatgrass by year 3 but also decreased the native palatable western wheatgrass. Mowing was a less effective weed control practice than grazing. Vegetative basal cover and aboveground primary production varied primarily with year. Common management practices for revegetation/restoration currently use herbicides and mowing as weed control practices and restrict grazing in all stages of development. Results suggest that allelopathic cover crop selection and opportunistic grazing can be effective alternative grass establishment and weed control practices. Susceptibility, resistance, and interactions of weed and seeded species to allelopathic cover species/cultivars may be a fruitful area of research.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Allelopathic cover crop prior to seeding is more important than subsequent grazing/mowing in grassland establishment
Series title Rangeland Ecology and Management
DOI 10.2111/REM-D-10-00117.1
Volume 64
Issue 3
Year Published 2011
Language English
Publisher Society for Range Management
Publisher location Lakewood, CO
Description 10 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Rangeland Ecology and Management
First page 291
Last page 300