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Selenium is biologically important because (i) it is essential in animal and possibly plant metabolism, (ii) in many areas diets do not contain sufficient Se to meet, animals' needs, and (iii) in other areas it is toxic to animals when it occurrs in high concentrations in soil, water, plants, fly ash, or in aerosols. Animals require 0.05 to 0.1 mg Se/kg in their diets to prevent Se deficiency but suffer Se toxicosis when dietary levels exceed 5 to 15 mg Se/kg. The earth's crustal materials generally contain 50 mg Se/kg and more often contain

The Pathfinder Uranium Mine which is located in southeastern Wyoming, was actively mined during the 1960's-1980's. Reclamation involved returning the spoil/overburden and replacing the salvaged topsoil. The area was revegetated in 1974-1977, but was not grazed until 1980-85. A grazing experiment was then conducted to determine solubility of mineral elements in soil, uptake by plants and absorption by grazing animals. Blood sera were collected at 28-30 day intervals during the three grazing/growing seasons in 1980-1982. Blood sera samples were frozen and later analyzed by ICP. When compared to published data, plants on the reclaimed site contained lower concentrations of Ca, Mg, Mn, P, and Zn; but higher concentrations of Cd, Cr and Ni than plants on adjacent undisturbed sites. When compared to expected blood sera data, animals grazing on the reclaimed site had lower concentrations of B. Ca, Cu, Mg, and Na; but higher concentrations of Cr and Fe than would be expected for most grazing animals. Livestock producers are advised to provide supplements of Ca, Mg, Mn, P, and Zn to minimize deficiency of these elements in livestock nutrition when grazing these reclaimed lands.

HiMag is an experimental cultivar derived from Missouri 96 (Mo96) and Kentucky 31 (K31) tall fescue (Festuca arundinacea Schreb.) parentage for increased calcium (Ca), magnesium (Mg), and reduced potassium (K)/ (Ca+Mg). Our objective was to determine productivity and mineral characteristics of endophyte-free (E-) HiMag in relation to standard tall fescue cultivars when grown in the Southern Piedmont Land Resource Area. In experiment 1, HiMag (E-) and K31 (E-) were grown at two levels of phosphorus (P), K, and lime additions to both severely eroded, and noneroded Cecil soil (clayey, kaolinitic, thermic family of Typic Hapludults). Herbage Ca and Mg were greater and K/(Ca+ Mg) and yield were less for HiMag than for K31. Phosphorus and K concentrations were not different. Herbage yields, P, Ca, and Mg concentrations were increased by P, K, and lime additions. In experiment 2, HiMag(E-), K31(E-), endophyte-infected K31(E+), Mo I(E+), Mo II (E+), and AU Triumph (E-) were planted either in a prepared seedbed or planted without tillage into the Cecil soil. HiMag yields were not different from Mo-I, Mo-II or K31(E±), but were less than

Canola (Brassica napus) grown as a selected plant species for field phytoremediation of selenium (Se) may be harvested and utilized as Se-enriched forage for marginally Se-deficient lambs and cows. Two field studies were conducted under controlled conditions to evaluate the accumulation of Se into different animal tissues, including blood, excreta, and milk. In Study 1, treatments consisted of feeding lambs freshly cut Se-enriched canola (containing approximately 4 mg Se kg(-1) DM) or control canola (containing

Selenium (Se) occurs in various forms in soils, including inorganic selenite and selenate and organic selenomethionine. Plant uptake of the inorganic, but not the organic forms, has been studied extensively. Organic-Se uptake was therefore examined in two-grooved milkvetch (Astragalus bisulcatus (Hook.) Gray), a Se-accumulating forb, and western wheatgrass (Pascopyrum smithii (Rydb.) Love), a non-Se accumulating grass. Plants were grown for 56 days in nutrient culture enriched with 1 or 2 mg Se liter-1 as sodium selenite or 0.3 or 0.6 mg Se liter-1 as Se-DL-methionine or Se-DL-cystine. Growth was not affected by the Se treatments. Selenium concentrations in shoots were proportional to nutrient-solution concentrations for both species grown in sodium selenite and selenocystine, and for wheatgrass when grown in selenomethionine. Selenium concentrations in milkvetch were not increased by the higher concentration of selenomethionine. Shoots of milkvetch, growing in the low-Se treatment contained 243, 283, and 47 micrograms Se g-1, for the sodium selenite, selenomethionine, and selenocystine treatments, respectively, whereas values for the wheatgrass were 20, 32, and 17. Shoot:root Se concentrations were 1.2, 0.7, and 0.4 in milkvetch and 0.1, 0.5, and 0.1 in wheatgrass for the sodium selenite, selenomethionine, and selenocystine, respectively. Selenium is more readily transported to shoots in the accumulator plant, or conversely; there is a barrier to Se movement to shoots in the nonaccumulator plant. Wheatgrass contained sufficient Se to be of concern in animal toxicosis and because of greater dry matter yield accumulated as much or more Se than did the milkvetch.

The level of soluble tissue phosphorus (PO4‐P) may be correlated with the plant P nutritional status, but the amount extracted depends upon dry matter losses or the amount of enzymatic or heat—induced hydrolysis of organic P compounds during sample drying. Alfalfa (Medieago sativa L) and sugarbeet (Beta vulgaris L) plant parts grown under low and high soil P conditions, were freeze‐dried or oven‐dried at 40, 56, 70, or 100 C. Total K, P, and 0.35 N acetic‐acid‐soluble P (measured as PO ‐P) were determined. Dry matter losses were 0, 6.5, 3.6, 5.5, and 4.9 percent for the respective drying methods. The total‐P values, once corrected for dry matter losses, were not affected by the drying methods. The corrected PO4‐P values were 0.15, 0.17, 0.16, 0.16, and 0.19 percent, while the (PO4‐P)/P values were 0.63, 0.69, 0.67, 0.68, and 0.78 for each of the respective drying methods. The potential utility of extractable PO4‐P in describing the plants’ P nutritional status will depend upon rigorous sampledryi...

The hypothesis that excess dietary selenite ameliorates lead (Pb) toxicosis in domestic sheep was tested. Twenty 6–8-yr-old ewes fed alfalfa pellets were assigned to the following treatments: (1) control; (2) 9.8 mg Pb/kg body weight (b.w.)/d as PbCO3; (3) 3 mg Se/animal/d as Na2SeO3·5H2O; or (4) a combination of treatments 2 and 3. The gelatin-encapsulated salts were given orally. The study was terminated on d 104, by which time three animals in the Pb group and all five animals in the Pb+Se group had died. All remaining animals were slaughtered on d 104. Lead and Se concentrations were determined in six biweekly-collected blood samples and in soft tissues and bone. Sheep on the control and Se treatments had similar feed intakes, body weights, and tissue Pb levels. Those in the Pb+Se group had lower feed intake, but higher blood Pb values compared with the Pb group. Feeding either element increased (P

Nitrogen availability, as shown by short-term uptake by barley, was significantly higher on soils from burned than from unburned areas 10 months after burning. Increased soil-nitrogen concentrations were observed at all depths on the burned as compared with the unburned treatment.