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).
Danielle Treadwell, Center for Environmental Farming Systems. Goldsboro, NC.
We’re developing an organic, no-till, sweet potato production system for our growers here in North Carolina. Compost was applied in the fall. Cover crops were seeded using a Brillion cultipacker, which served two purposes: seeded the cover crops as well as flatten the tops of the hills that were made following compost. In the spring, when vetch was at mid-bloom, the cover crops were killed by rolling with the Brillion cultipacker. Ideally, the cover crops should be rolled in all the same direction for ease of transplant. Over the three years that we’ve been working on this system, the dry matter production of the rye has ranged from 3000-8000 lbs per acre. We’ve found that we get the most weed suppression with an increase in dry weight of rye.
This is the residue remaining sixty days after transplanting sweet potato. Mostly what remains is the rye, although we do have some vetch re-growth. I don’t perceive this to be a problem. We’ve had a fair amount of this residue remaining at harvest, which generally is about 100 days after transplanting for Beauregard.
This area has been hand-weeded three times. These plants are about sixty days old now. They were planted in late-June. The foliage growth that you see here is right about maximum.
These sweet potato transplants are actually sections of vine that are known as slips. Generally they are without roots and they were transplanted using a no-till transplanter designed by Ron Morse of Virginia Tech. The transplants are spaced about ten and a half inches apart and you can see here how the residue was cut with the coulter and slightly moved to the side, but yet it remains fairly well intact and undisturbed following the day of transplant.
One of the biggest concerns for organic growers is weed suppression. Beauregard is the dominant variety for sweet potato growers in our area here in North Carolina, but it’s slow to vine out, so we’re not really convinced that this is the best variety to use. Other varieties such as Jewel are very quick to vine out, but they have less yield than Beauregard. Fernandez might be another option. It has an intermediate vining speed between Beauregard and Jewel. It also has an intermediate yield.