An Evaluation of Organic Transition Approaches for the Northern Great Plains.

Cover crops have become increasingly popular due to their ability to provide a range of ecosystem services and as a way of introducing diversity into annual crop rotations. For organic producers, cover crops are essential for building soil organic, increasing soil fertility and reducing weed pressure. The use of cover crops may also help facilitate conservation tillage management in organic production systems. Research has demonstrated that the long-term use of cover crops and reduced tillage can both result in enhanced soil microbiological communities that subsequently enhance nutrient cycling. In addition, due to the limited number of tools at their disposal, organic producers are challenged with the task of reducing the weed-seed bank during the 3-year organic transition process. Controlling weeds during this phase is critical for long-term crop productivity. Furthermore, with the majority of honey bee colonies that pollinate U.S. crops residing in the northern Great Plains for much of the year, full-season cover crops can provide a sustained forage source for pollinators and may help mitigate the well-documented problem of declining wild and managed bee populations. We will present the foundation for a study designed to evaluate six different organic transition approaches. The study will evaluate three objective-based, conservation tillage cover cropping systems for providing pollinator services, weed suppression services or soil-building benefits during the organic transition phase in the northern Great Plains. Other treatments include a multipurpose cover crop mixture, a perennial alfalfa-grass mixture and a 3-year annual crop rotation check. In addition, in order to evaluate trade-offs between ecosystem services provided by cover crops and forage benefits for livestock, a grazing component has been added. Findings from this long-term study will provide producers who are interested in transitioning some or all of their acreage to organic information on the costs and benefits associated with each transition approach.