Understanding Beneficial and Pathogenic Microorganisms Impacting Production of Forage Crops

Year round grazing for beef cattle provides an advantage to farmers and ranchers by limiting the amount of supplemental feeding that is required. Typical grazing systems within the southern Great Plains (Oklahoma and Texas) consist predominantly of Bermudagrass, as well as other warm season grasses, and winter annuals such as winter wheat. However, forage deficits often exist in the fall and late winter, and environmental conditions can reduce stand longevity. The Samuel Roberts Noble Foundation is developing system-based approaches to enhance forage production by integrating the perennial forages tall fescue and alfalfa to extend the grazing season. In addition, the interaction of microorganisms such as symbiotic and pathogenic fungi and bacteria associated with these forage species are being explored. Beneficial nitrogen-fixing bacteria and fungal symbionts (Sebacina and Epichloë species) have been harnessed and evaluated to lower agricultural inputs, such as fertilizer, and provide protection against some biotic and abiotic stresses. In addition, Phymatotrichopsis omnivora is a devastating fungal root pathogen that can greatly reduce alfalfa production in the southern Great Plains. Each of these plant-microbe interactions is being studied at multiple levels to gain insight into host performance under various environmental conditions.