Livestock producers in the high elevation areas of Wyoming and Colorado depend on hay meadows for their forage production. Because of limited precipitation and low fertility, producers have routinely practiced flood irrigation in these meadows and apply high rates of nitrogen fertilizer to guarantee sufficient production. Yet, these integral meadows are underperforming, expensive to manage, and harmful to the environment under current practices. For example, creeping and meadow foxtail have become dominant because of their competitive advantage in the flood irrigated anoxic environments and foxtails’ high affinity for nitrogen and their sod forming characteristics. Negative impacts proliferate through century long seasonal flood irrigation coupled with cool temperatures that have led to the development of a dense thatch that captures organic nutrients making them unavailable for hay crop use, affecting forage yield.
Microbial inoculants, or biofertilizers, containing living microorganisms, stimulate microbial activity and improve mobility of nutrients in soil. They are potentially useful for enhancing plant growth, increasing forage yield, and enhancing soil health. In response to producers’ concerns, University of Wyoming graduate student Rael Otuya is studying the impact of biofertilization or the use of microbial inoculants on soil health, forage quantity, and quality in these hay meadows. If the potential of applying microbial inoculants proves successful, producers may be able to reduce reliance on chemical fertilizers, reduce costs, optimize yields, foster carbon sequestration, and promote soil health. Otuya estimates costs could be reduced up to $30/acre.
Using both a field study design and controlled environment experiments, Otuya’s project is evaluating the response of the soil microbial community, nitrogen pools and mineralization, and forage quantity and quality to biofertilization. She is using single inoculants and complementary microbial inoculation combinations in the management of plant nutrients by selecting inoculants that acquire nutrients through fixation, solubilization or transformation. Results will be shared with Wyoming and Colorado producers at workshops, meetings, and site tours.
“At the end of the day, it’s the producers we’re thinking about,” says Otuya. “We hope that the yields we see will be the same or higher with reduced N applications. This benefits the producer and the environment.”