Current Status and Soil Biology Impacts of Organic Conservation Tillage in the US Great Plains

Abstract

Crop production and soil quality benefits following adoption of conservation-tillage practices in conventional dryland agriculture are well documented. These successes have spurred interest among farmers and researchers in developing conservation-tillage practices that can be used in organic cropping systems. However, achieving long-term, consistent weed control has been cited as a major obstacle preventing the adoption of organic conservation-tillage systems in the US Great Plains, particularly when farm scale prevents hand removal of weeds and intensive tillage could result in unsustainable soil erosion. In particular, Canada thistle (Cirsium arvense (L.) Scop), field bindweed (Convolvulus arvensis L.), and other creeping perennial weed species pose particular obstacles to the continued use of conservation-tillage practices following the first 2 to 4 years after adoption, although annual weeds (e.g., downy brome [Bromus tectorum L.]) and simple perennials (e.g., dandelion [Taraxacum officinale Weber]) can also become problems. To fill this knowledge gap, researchers and farmers have explored several practices including cover crop mulch, grazing, and acetic acid applications to reduce and even eliminate tillage and suppress weeds in organic environments across the US northern Great Plains region. In this paper, we summarize efforts to develop long-term, conservation-tillage systems in organically managed environments and how these practices impact the soil biological community and discuss how successful adoption of conservation-tillage practices by organic farmers may revolutionize organic farming in the US Great Plains and similar climatic regions globally.