Agronomic and Economic Effects of Harvesting Legume Cover Crops at Varying Maturities

Final Report for FNE04-511

Project Type: Farmer
Funds awarded in 2004: $7,128.00
Projected End Date: 12/31/2008
Region: Northeast
State: Vermont
Project Leader:
Kate Duesterberg
Cedar Circle Farm
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Project Information


Note to readers, attached is the complete final report for FNE04-511.

We had grown blackeyed peas and pinkeyes for an ethnic market in central Massachusetts after customers requested that we try growing them. We only grew small amounts but we realized that we could grow them in New England. We had read about their characteristics as a cover crop, so we decided that we would try to grow them as both a cover crop and a cash crop. But, we did not want to sacrifice the fertility benefits for the sake of a cash crop. We decided to try several peas to see if they would still produce sufficient fertility and produce a cash crop as well.

We conducted a forage analysis at three stages of plant development. Our first analyzes were done at the peak of vegetative stage. Our second analyzes was done at peak green pea production. Our third analyzes was done at peak dry pea stage.

Results from the forage analysis and from weights taken from each cutting at each stage indicated that plowing the peas down to either the vegetative stage or the green pea stage for both California Blackeyes #5 and Purple Podded Pinkeyes would provide the grower with excellent biomass and considerable nitrogen. In fact, for both of these peas, the green pea stage produced approximately the same amount of biomass as the vegetative stage and produced more nitrogen. So, at this stage, growers could take off a green pea crop and still get excellent fertility results and excellent weed control. If growers waited until the dry bean stage the fertility dropped significantly and the weed control effect was lost. We eliminated Mississippi Pinkeyes because although they produced excellent crops of peas, they didn't produce nearly as much biomass, they produced less nitrogen and they did not suppress weeds.

We think this was a valuable project because it illustrates that farmers and agronomists may not know the effects of pulling a cash crop off of a fertilizer crop of cowpeas. They commonly held belief is that extracting a cash crop from a fertility crop reduces the fertility value. That was certainty not the case with these peas. In fact, when the crop was at the peak green pea production stage, it produced as much biomass (or more in the case of the Purple Podded Pinkeyes) and more nitrogen. We think this illustrates that we need to keep rethinking our basic premises. We have a saying on the farm that goes like this: if we are still farming organically the same way we are farming now, in five years, we have failed. We all have a lot to learn. If we all share our little breakthroughs then we can leapfrog over problems together, instead of all of us trying to reinvent the same wheel. Hopefully this little study will help the leapfrog process.


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  • Vern Grubinger


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.