Weed 'Em and Reap Part 2: Reduced tillage strategies for vegetable cropping systems [DVD]. A. Stone. 2006. Oregon State University Dept. of Horticulture. Corvallis, Oregon. Available at: http://www.weedemandreap.org (verified 17 Dec 2008).
Ken Fager and Robert Walters. Center for Environmental Farming Systems. Goldsboro, NC.
This piece of equipment is a roller and it’s a tractor-mounted tool designed to knock over and flatten cover-crop forages. The second purpose of this roller is to intermittently damage the stems of the cover crop, so that they resist the tendency to spring back to the original, vertical position. The damage, also known as a crimp, renders the forages vulnerable to desiccation and permanent wilt. The third purpose of the roller is to position the forages in one direction so that planting is facilitated without dragging in tangled stems and leaves.
We’re not sure exactly who invented it, but we do know, or it’s been reported that it has been in use in Latin America, particularly the countries of Brazil, Argentina, and Paraguay as a residue management tool by subsistence growers there in conservation tillage systems.
This roller/crimper was custom-built by the Kelly Manufacturing Company for North Carolina State University. It is not an implement that you can go out and purchase on the market. Most growers who have a shop and some mechanical ability can build one of these just like this.
The crimping action of the roller/crimper is dependent on three factors. First and foremost, the weight of the roller itself. This is all constructed of heavy-gauge steel, however there is an ability with this roller to add water to the drum and thus increase the ballast and therefore the down pressure. Another factor is the lift mechanism. The three point hitch, we found, needs to be in a lowered position, so that you maximize the down pressure on the parallel linkages and on the drum as it rolls across the surface. Now ground speed is also important, and we’re not exactly sure what the ideal ground speed is. But we feel that a speed of somewhere between three and six miles per hour would be optimum for maximizing crimping action of the roller. One of the unique design features of this roller/crimper is the incorporation of a set of parallel linkages that serve to pivot the roller/crimper drum vertically as it moves across the soil surface.
Normally when one’s trying to kill a cover crop, one would look for flowering in the cover before trying to roll kill it. The millet standing here before me, most of it has either flowered 2 weeks ago or is currently flowering. Consequently it would be a good time to roll it.
This is what the pearl millet mulch looks like after it's been rolled and crimped. You can see we have a nice layer of living mulch. The stems and the roots are intact and it’s lying prostrate on the surface, which is what we want.
We’ve never actually tried to roll and crimp pearl millet. This is the first time. We are getting some crimping action on the stems as well, although not as much as we’d like to see and we expect to get on other small grains like rye and foxtail millet. But the crimping is quite evident and the stem is broken, which is what we want. This will make it very easy for us to come back in here afterwards and run the no-till transplanter through this field and set our plants.