Submitted to: International Journal of Wildland Fire
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Sustainable grassland management balances livestock production and conservation of ecological properties and processes that support biodiversity and ecosystem service delivery. While mineral nutrition is important for livestock health and performance, the impact of prescribed fire on mineral concentration of forages, especially in the northern US Great Plains, remains unknown. We determined how burning affects the mineral concentration of available forage early and late in the growing season in mixed-grass prairie in south-central North Dakota from 2017-2020, from plots burned either 1 or 2 years prior, or not yet burned at all. Samples were analyzed for calcium, phosphorus, magnesium, potassium, copper, iron, manganese, and zinc concentration. Burning increased forage mineral concentration across most minerals. Phosphorous, potassium, copper and zinc were higher in burned areas in late spring and summer, while calcium, magnesium and manganese were only higher during the late summer. Iron was increased in longer time since fire patches during the late season sampling. Greater mineral concentration in forage on burned areas has the potential to reduce mineral supplementation costs and improve cow performance through enhanced immune function and reproduction.

Technical Abstract: Sustainable grassland management balances livestock production and conservation of ecological properties and processes that support biodiversity and ecosystem service delivery. While a broad literature indicates the conservation benefits of patch-burn grazing, benefits for livestock production have emerged more slowly, and little of this latter research has focused on grazer nutrition. Mineral nutrition is important for livestock health and performance, but the impact of prescribed fire on mineral concentration of forages, especially in the northern US Great Plains, remains unknown. We determined how burning affects the mineral concentration of available forage early and late in the growing season. Data were collected on mixed-grass prairie in south-central North Dakota from 2017-2020. Vegetation was clipped from recently burned, one year since fire, two years since fire, and unburned patches at the same sampling points in spring and late summer. All samples were analyzed for calcium, phosphorus, magnesium, potassium, copper, iron, manganese, and zinc concentration. Burning increased forage mineral concentration across most minerals. Phosphorous, potassium, copper and zinc were higher in burned areas in late spring and summer, while calcium, magnesium and manganese were only higher during the late summer. Iron was increased in longer time since fire patches during the late season sampling. Greater mineral concentration in forage on burned areas has the potential to reduce mineral supplementation costs and improve cow performance through enhanced immune function and reproduction.