Greenhouse Gas Emission and Crop Productivity From the Contrasting Management Approaches In Dryland Winter Wheat-Fallow of the Northern High Plains.

Dryland winter-wheat fallow production in the Northern High Plains is mostly done conventionally (tillage and chemical weed control), but also under no-tillage (chemical weed control only) and organic (tillage only) approaches. With the growing interest in obtaining high premium for organically-certified winter wheat, there is an increased interest in transitioning to organic production. However, current organic management strategies are tillage-intensive and do not provide environmental services that grant long-term sustainability which was previously demonstrated by a low soil carbon and nitrogen content. We hypothesize that dryland organic winter-wheat production in Northern High Plains also results in higher greenhouse gas (GHG) emissions compared to no-till practices, but comparable to conventional systems. To our knowledge, the information on GHG inventories from this ecoregion is lacking. Moreover, while transitioning to organic farming, converting from the no-till system may provide a better ecosystem services for the organically grown crops by higher soil organic matter content, improved soil conditions and reduced soil weed bank. This can limit the frequency of intensive tillage operations needed to control weeds and most importantly, lower GHG emissions. We established a long-term monitoring on sites under conventional, no-till and organic winter wheat-fallow scenarios. to determine greenhouse gas emissions (GHG), soil, plant residue, crop yield and weed species population. In addition, a series of additional sites are established to determine the impact of the transitioning phase from the conventional and no-tillage to organic production on soil and plant nutrient dynamics. This paper will report the results of the first year of findings.