Influence of Temperature on the Yield and Chemical Composition of ‘Vernal’ Alfalfa at First Flower1
- Dale Smith2
The first-flower stage of growth of ‘Vernal’ alfalfa (Medicago sativa L.) was reached in 21 days in the warm (W) temperature regime (32 C day/24 C night), but not until 37 days in the cool (C) regime (18 C/10 C). Herbage yields were considerably higher in the C than in the W regime. The first-flower herbage in the C regime was highest in concentration of in vitro digestible dry matter, nonstructural carbohydrates, Ca, Mg, Ba, and Sr, but was lowest in protein, amino acids, ether extract, total ash, P, K, Al, Fe, B, Cu, Zn, and Mn. Composition of the leaflet and stem fractions was also in this order, but for a few exceptions. Crude fiber percentage was highest in the leaflets of the W regime and in the stems of the C regime, but there was no difference for the total herbage. All chemical constituents analyzed were in higher concentration in the leaflets than in the stems, except for reducing and total sugars, crude fiber, and K. Even though the soil contained 560 kg/ha of exchangeable K, the herbage from the C regime contained less than 1.5% of K, while that in the W regime contained over 2%.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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