Kernza in Wyoming: Perennial grains for vulnerable lands

Kernza (Thinopyrum intermedium), among the first perennial grain crops ever developed, could provide an alternative to wheat-fallow for vulnerable agroecosystems while building soil health. From 2021-2023, Kernza was planted for the first time in Wyoming, where the semiarid landscape presents unique challenges yet stands to particularly benefit from a perennial crop. To determine Kernza's agroecological viability in this climate, we measured yield and biomass in dryland Kernza, wheat-fallow, and undisturbed perennial grassland at a working farm in Chugwater, Wyoming and in irrigated Kernza from research plots in Lingle, Wyoming. To compare soil health in these fields, we measured microbial biomass, enzyme activities, eleven organic matter pools, and bacteria and arbuscular mycorrhizal fungi community composition in bulk and rhizosphere soils. Kernza produced significantly lower grain yields than wheat, though it could provide flexibility as a perennial forage crop during drier years. Few differences were observed in bulk soil from Kernza and wheat fields, likely due to the short nature of the study. However, rhizosphere soil from Kernza contained higher labile organic matter and microbial activity than wheat, and an arbuscular mycorrhizal fungal community more similar to perennial grassland than to wheat. Kernza fields also contained over twice the root biomass as wheat fields. Despite low yields, Kernza's ecological benefits and added flexibility as a forage crop may make it a viable option for some semiarid wheat farmers.