You may recall that I planted some experimental cover crops this year hoping they'd be cut-and-come-again mulch producers. The ones I was most excited about --- pearl millet and sorghum-sudangrass hybrids --- aren't really living up to their potential. These warm-season grasses remind me of corn in that they grow big stalks that require interim weeding and mulching, but the cover crop versions actually appear to produce less biomass than corn does. As a result, I feel like I would have been better off planting these beds with sweet corn or field corn then using the corn stalks if I wanted to harvest biomass from warm-season grasses. All told, I'm not very impressed by the warm-season grasses, even though sorghum-sudangrass hybrids are reputed to produce more biomass per acre than any other cover crop.

On the other hand, soybeans as a cover crop continue to intrigue me. The soybeans we planted on June 10 are just starting to bloom, so I chose one patch to scythe a few inches above the ground in hopes the plants will grow back and let me cut again in a few more weeks. While I was at it, I also scythed the buckwheat growing next door (planted two weeks later) and then I replanted the whole patch with new buckwheat seeds.

Before I go into the results, I should tell you that I'd been out cutting pasture weeds before embarking on this experiment, so my scythe was a little dull. As a result, the tool yanked up (rather than cut down) perhaps 10% of the soybeans. Gathering up the cut tops was easy, but I only got an armload out of this whole patch, which would probably be about enough to mulch 15 square feet in the garden. Lazily, I instead simply tossed the cut tops onto our compost pile.

A perhaps better use of a soybean cover crop (although more expensive since the initial seed investment doesn't go as far) is to pull up entire soybean plants then use the legumes to feed the next crop. I yanked up the soybean plants in the bed pictured above less than a week ago, piling the cover crops in between rows of new sweet corn. The soybeans are so high in nitrogen that they're already disintegrating into the soil six days later, meaning they'll feed the corn plants by the time the roots reach the center of the bed. Whether or not the soybeans produce enough nitrogen to feed an entire bed of corn with no additional amendment remains to be seen. I'll keep an eye on leaf color and report back in a few more weeks.