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At the intersection of food, soil, climate, farming and water.

Sunn Hemp: A potential cover crop for Wisconsin?

This summer, the Institute initiated an evaluation of Sunn hemp (Crotalaria juncea L.) as a potential cover crop for Wisconsin. A tropical, rapid-growing legume, it has demonstrated its ability to produce large biomass and nitrogen yields in the Southern U.S. and as far North as Illinois. It also has potential to suppress weeds because of its rapid growth and has been shown to reduce root-knot nematode populations. Because it requires warm conditions, we envision using it during the summer months for several applications including organic transition, reinvigoration of certified organic land and on prevented-plant acres. We currently don’t have a good warm-season legume option, so if successful, Sunn hemp would fill this niche well.

Currently under investigation are the effects of planting date and seeding rate on productivity and companion planting with sorghum-sudangrass, a warm season grass using various seeding rate combinations. The goal of these studies is to find the optimum combinations to maximize productivity at the lowest possible seed cost. As with all our cover crop screening work, we also keep a close eye on the plots, watching for potential problems including attraction of insect pests. Stay tuned for further developments!