Protein and Mineral Concentrations of Selected Wild Sunflower Species1
- Gerald J. Seiler2
Although wild sunflowers (Helianthus spp.) can be components of pastures, hay, and silage, limited information is available on the forage-quality of sunflower species. The objective of this study was to evaluate wild species of sunflower for protein and mineral concentrations. The experiment had a completely randomized design with three replications. The plots were planted in Pullman clay loam (fine, mixed, thermic Torrertic Palenstolls) soil. The leaves and stems of 26 perennial and one annual wild Helianthus spp., and a commercial annual sunflower hybrid planted in pure stands were evaluated at vegetative, flowering, and fruiting stages to ascertain their nutritive value for ruminants. Crude protein (CP) of 140 g kg−1 and above occurred in the leaves of 11 of the 26 perennial species at the vegetative stage. At the flowering stage, only two of the 26 perennial species had CP concentrations above 140 g kg−1 in the leaves. Willow-leaf sunflower (Helianthus salicifolius Dieter) had the highest leaf CP (180 g kg−1) at the vegetative stage. Wild annual sunflower (H. annuus L.) and the commercial ‘Hybrid 894’ had leaf CP concentrations above 140 g kg−1 at all stages of maturity. Crude protein concentrations generally declined as plants matured. Crude protein concentrations of seeds were higher in most of the perennial sunflower species than in the wild annual or commercial sunflower. Nutritionally, adequate amounts of Ca (2 to 5 g kg−1), Mg (2 g kg−1), and K (8 g kg−1) were present in the leaves and seed of all wild sunflower species and commercial sunflower. The leaves and stems of all species except the Arizona sunflower (H. arizonensis R. Jackson) had sub-optimum P levels for high-producing ruminants. Nutritionally adequate amounts of P (3 g kg−1) were present in seeds of all sunflowers examined. At the vegetative stage, nutrient level of some of the wild perennial sunflowers is comparable to that of cultivated sunflower. Ruminants most likely would not graze pure stands of wild sunflower, but would graze it in mixed stands with other forbs and grasses. The wild sunflower species may also be incorporated in hay or silage and still offer a satisfactory nutrition level.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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