Potential of Forages to Diversify Cropping Systems in the Northern Great Plains

Abstract

Cultivated forage crops are grown on almost 12 million ha on the northern Great Plains. This paper reviews the benefits of diversifying annual crop rotations with forage crops and highlights innovations in forage systems. Agronomic benefits of rotating forage crops with annual grain crops include higher grain crop yields following forages (up to 13 yr in one study), shifts in the weed population away from arable crop weeds, and improved soil quality. Perennial legumes in rotation also reduce energy requirements by adding significant amounts of N to the soil. Soil water availability may limit the extent to which forages benefit following crops. Under semiarid conditions, forages can actually reduce yields of the following crops, and as such, tillage practices that conserve soil water have been developed to partially address this problem. Forages in rotation provide environmental benefits, such as C sequestration, critical habitat for wildlife, and reduced NO3 leaching. A wider range of annual plant species are now used in forage systems in an effort to extend the grazing season and to maximize use of water resources. Intensive pasture management using cultivated forages is on the increase as is the use of alfalfa (Medicago sativa L.) in grazing systems; in some cases, bloat‐reduced alfalfa cultivars are used. Pasture‐based systems appear to provide benefits for both animal and human health and arguably the health of the environment. Pasture systems are less nutrient exhausting than hay systems. As a result, nutrient management strategies will differ in the following crop. Additional research is required to optimize the role of cultivated pastures in grain‐based cropping systems.

Annual forage impacts on dryland wheat farming in the Great Plains

“…Others reached similar conclusions (Entz, Bullied, & Katepa-Mupondwa, 1995;Entz et al, 2002;Krall & Schuman, 1996;Kumar et al, 2019;Sulc & Franzluebbers, 2014), but many of these studies focused on alfalfa (Medicago sativa L.) and, to a lesser extent, other perennial forages [e.g., red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.)] (Power, 1991). Some of the research also occurred in wetter eastern areas and the adjacent Canadian Prairie Region (e.g., Badaruddin & Meyer, 1989;Entz et al, 2002). While informative, the application of this research is limited when considering the potential of annual forages in dryland wheatbased farming in the Great Plains.…”

“…These results suggest that forages can be used to intensify wheat-based dryland farming in semi-arid regions. Others reached similar conclusions (Entz, Bullied, & Katepa-Mupondwa, 1995;Entz et al, 2002;Krall & Schuman, 1996;Kumar et al, 2019;Sulc & Franzluebbers, 2014), but many of these studies focused on alfalfa (Medicago sativa L.) and, to a lesser extent, other perennial forages [e.g., red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.)] (Power, 1991). Some of the research also occurred in wetter eastern areas and the adjacent Canadian Prairie Region (e.g., Badaruddin & Meyer, 1989;Entz et al, 2002).…”

“…Reducing the frequency of fallow in dryland cropping systems can provide agronomic and environmental benefits through increased production, improvements in nutrient and water cycling efficiency, and enhanced soil quality (Entz et al, 2002;Ghimire et al, 2018;Peterson & Westfall, 2004). Inclusion of annual forages in wheat-based cropping systems offers opportunities to capitalize on these benefits while offering land managers a form of production with multiple uses (e.g., forage, grazing, or grain).…”

“…Incorporating forages into semi-arid dryland wheat systems can suppress weeds (Entz et al, 2002;Meiss et al, 2010;Sanderson, Johnson, & Hendrickson, 2018). Many of the studies reviewed by Entz et al (2002) and the research reported by Meiss et al (2010) focused on perennial forage species, particularly alfalfa, although some researchers investigated the impacts of annual species on weeds (e.g., Lenssen & Cash, 2011 Schoofs and Entz (2000). There were no advantages in weed density of the two other weed species inventoried {green foxtail [Setaria viridis (L.) Beauv.]…”

“…Likewise, the use of annual forages for controlling disease and insect pests in dryland wheat systems may increase. However, knowledge of annual forage impacts on disease and insect pests in dryland wheat systems is limited (Entz et al, 2002). Future research should consider the importance of annual forages in disease and insect pest suppression as a supplement to ongoing studies addressing weed management tradeoffs in dryland wheat systems.…”