Agronomy and Crop Sciences Commons^™

Refining Thresholds In Coupled Fire–Vegetation Models To Improve Management Of Encroaching Woody Plants In Grasslands, Dirac L. Twidwell Jr, Samuel D. Fuhlendorf, Charles A. Taylor Jr, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

1. Restoration priorities are typically established without quantitative information on how to overcome the thresholds that preclude successful restoration of desirable ecosystem properties and services. We seek to demonstrate that quantifying ecological thresholds and incorporating them into management-oriented frameworks provide a more comprehensive perspective on how the threshold concept can be applied to achieve restoration goals.

2. As an example, restoration actions have been largely unsuccessful when based on prevailing ecological knowledge of fire-based thresholds in nonresprouting Juniperus woodland. We build on previous threshold-based research and link well-established models from applied fire physics with a widely applied ecological positive feedback …

Sorghum Transformation: Overview And Utility, Tejinder Kumar, Arlene Howe, Shirley Sato, Ismail M. Dweikat, Tom E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Over the past decade genomics resources available for sorghum have rapidly expanded (Paterson Int J Plant Genomics 2008:6, 2008), these resources, coupled with the recent completion of the genome sequence which is relatively small in size (730 Mb) (Paterson et al. Nature 457:551–556, 2009) makes sorghum a rather attractive species to study. Moreover, the USDA germplasm system maintains 42,614 accessions, of which more than 800 exotic landraces have been converted to day length-insensitive lines to facilitate their use in breeding programs. In addition, a set of EMS mutation stocks developed by the USDA Plant Stress and Germplasm Development Unit in …

Increased Weed Diversity, Density And Above-Ground Biomass In Long-Term Organic Crop Rotations, Samuel E. Wortman, John L. Lindquist, Milton J. Haar, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

While weed management is consistently a top priority among farmers, there is also growing concern for the conservation of biodiversity. Maintaining diverse weed communities below bioeconomic thresholds may provide ecosystem services for the crop and the surrounding ecosystem. This study was conducted to determine if weed diversity, density and biomass differ within and among organic and conventional crop rotations. In 2007 and 2008, we sampled weed communities in four long-term crop rotations near Mead, Nebraska, United States using seedbank analyses (elutriation and greenhouse emergence) and above-ground biomass sampling. Two conventional crop rotations consisted of a corn (Zea mays) …