Western Research and Demonstration Farm
Planting cover crops to simultaneously establish native prairie seedlings and prevent weed invasion is a common management practice. The idea is based on the assumptions that the cover plant will act as a nurse plant to the prairie seedlings and that it will have a positive effect on seedling recruitment by increasing weed suppression and by lowering the harmful effects of high evaporation and light availabilities. Furthermore, plowed ground is ideal habitat for a host of weedy species that have higher germination and early growth rates, especially above ground, than do prairie species. Cover crops could also potentially reduce the amount of soil erosion that occurs during planting. However, the evidence supporting the benefits of cover crops is mostly anecdotal and has been challenged. Clearly, further scientific evidence is needed on the efficacy of cover plants, whether cover plants have a facilitative or competitive effect on prairie seedlings, as well as how these processes work. Of particular interest is whether the nurse plant effect is caused by light suppression or water uptake.
Iowa State University
Wilsey, Brian J. and Blong, Andrea, "Native Cover Crops: Germination and First-Season Cover and Biomass" (2005). Iowa State Research Farm Progress Reports. 1308.