Kernza® (grain harvested from intermediate wheatgrass; Thinopyrum intermedium) is becoming the country’s first widely available perennial grain crop, which has potential to be a profitable alternative crop that greatly decreases the environmental impacts associated with US agriculture. The ecological sustainability of Kernza could be further improved using legume intercropping practices to reduce or eliminate synthetic nitrogen fertilizer requirements and improve soil health. Preliminary data show that Kernza can be effectively grown in mixture with legumes, but the agronomic practices needed to manage crop interactions to optimize profitability and ecological services are not well established and require regional assessment. This project will test four different legumes, each intercropped with Kernza as a biculture, in two experiments that will occur at six on-farm and three institutional research sites in Minnesota, Wisconsin, and Kansas. One objective is to identify legume intercrops that increase Kernza yield and reduce or eliminate nitrogen fertilizer needs. We will measure Kernza grain yield and nitrogen fertilizer offsets from atmospherically-fixed nitrogen provided by the legumes, and determine the economic implications related to these outcomes. We will quantify the effects of legume species on soil health characteristics, carbon sequestration and nitrogen transformations. Project partner Green Lands Blue Waters will develop and facilitate a Kernza grower network that will guide the design and execution of experiments and outreach and education events. Six farmers from three states of this network will host the on-farm Kernza legume intercropping experiments. The Kernza grower network will also include a panel of three experienced Kernza farmers to advise researchers and on-farm research hosts on Kernza management and the dissemination of our results. Early-adopter Kernza farmers are well-respected leaders in their community and well positioned to influence a much wider group of farmers in their networks, creating a multiplier effect of credible peer-to-peer farmer knowledge sharing. An outcome of this project will be the expansion of the grower network by recruiting future Kernza growers during our outreach and education events, which will include field days and winter workshops that demonstrate how to establish and manage Kernza-legume intercrops. Additional outputs will include a management document on Kernza-legume intercropping for Minnesota, Wisconsin, and Kansas. The research experiments included in this proposal, and the Kernza grower network and associated farmer-to-farmer education and outreach activities, were based on farmer-identified needs and designed in collaboration with the farmers listed in the “Team Experience and Roles” section.
Project objectives from proposal:
Agronomic knowledge of legume-Kernza intercropping systems to improve Kernza yields while reducing costly nitrogen fertilizers. We will determine which legumes work best as intercrops in three states, and develop recommendations for managing legumes with Kernza. Ecological knowledge quantifying the soil health impacts of legume intercrops, including changes in nitrogen mineralization. Outreach activities improving grower connectedness and providing education; management document, field days, and winter workshops. Skills and awareness for farmers to successfully produce profitable Kernza yields without expensive synthetic fertilizers.