|Grings E E,|
|Haferkamp M R,|
|Heitschmidt R K,|
|Karl M G,|
Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 3, 1995
Publication Date: N/A
Interpretive Summary: Developing an effective mineral supplementation program for livestock requires an understanding of changes in forage mineral concentrations throughout the year. Several previous reports have shown the potential for mineral deficiencies. Moreover, mineral concentrations in herbage tend to vary with soil fertility, plant species, stage of plant maturity, availability of water, and tissue age. Limited information is available currently on concentrations of minerals in forages of the Northern Great Plains. Therefore, a study was conducted to evaluate variations in mineral concentrations of major forages in the Northern Great Plains. Herbage was sampled from 2 soils on 9 dates. Herbage was sorted by species grouping and by live and dead tissue classes and analyzed for calcium, phosphorus, magnesium, potassium, sodium, zinc, copper, manganese, and molybdenum. Minerals most likely to be found in quantities less than required for optimal animal production were phosphorus, sodium, potassium, zinc and copper. From this study, we conclude that tissue class plays a major role in influencing whole plant nutrient content for all macronutrients except sodium. Availability of different tissue classes may be used to assist in management decision- making regarding mineral status of forages and animal supplementation needs.
Technical Abstract: Mineral concentrations of range grasses are often below that required by grazing livestock. Limited information is available on forage mineral concentrations for the Northern Great Plains and there is little data on factors influencing concentrations of forage minerals throughout the year. Therefore, a study was conducted to evaluate spacial and temporal variations in mineral concentrations of major forage species in the Northern Great Plains. Herbage was sampled from 4 replicates on each of 2 soils in July, August, and September 1991, April, June, July, August, and September 1992, and April 1993. Herbage was sorted by species grouping and by live and dead tissue classes. Analyses on herbage included Ca, P, Mg, K, Na, Zn, Cu, Mn, and Mo. For western wheatgrass [Pascopyrum smithii (Rydb.) Love] and annual bromes [Bromus spp.], Zn and all macrominerals except Na were greater in live than in dead tissue. Live tissues of all other species groupings contained greater amounts of P and K than did dead tissue. Live tissue Mg concentrations were greater than dead tissue concentrations for other cool-season and warm-season grasses. Manganese concentrations were greater in live than dead annual brome tissues, Cu content was greater in dead tissue than live. Dead sedge tissue had greater concentrations of Ca than did live tissue. Soil type affected on several nutrients but this was partially related to soil effects upon composition of species groupings and live:dead ratios. Minerals most likely to be found in quantities less than required for animal production were P, Na, K, Zn and Cu.