Significance of Parts Other Than Blades and Stems in Leaf-stem Separations of Alfalfa Herbage
1975
Fick, Gary W. | Holthausen, Richard S.
Leaf-stem separations of alfalfa (Medicago sativa L.) herbage have been widely used, but designation of petioles, stipules, stem tips, and reproductive structures as leaves or stems has been inconsistent. The objective of this study was to characterize this material and thus establish a basis for including it with either the leaf blades or stems. Alfalfa herbage from the vegetative to the seedpod stages of development was separated into three fractions (blades, stems minus 3 cm of tip, and “other parts”) and analyzed to determine the total herbage represented by each part and the percentage in vitro true digestibility (IVTD) and crude protein (CP). From the bud through the seedpod stages the other parts represented a nearly constant 11% of the total herbage dry matter and contributed about 9 g of IVTD dry matter and 2 g of CP for every 100 g of herbage. The IVTD of the other parts was generally zero to five percentage units lower than that of the blades, but as much as 25 percentage units higher than the stems minus tips. The CP content of the other parts ranged from four to eight percentage units below the blades and from four to eight percentage units above the stems without tips. For the narrow range of cultivars and environments represented in this study, a two-way separation which removes stems minus the tip from the rest of the alfalfa herbage both combines morphological parts of similar digestibilities and facilitates a simple estimation of blade content.
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