Envirommental and Plant Growth Stage Effects on Composition and Digestibility of Crownvetch Stems and Leaves1
- G. A. Jung2,
- D. E. Brann3 and
- G. W. Fissel2
Crownvetch (Coronilla varia L.) has not been widely used for forage, partly because its forage quality has been reported as poor. Studies were undertaken to determine the effects of different environments and clipping schedules on composition and in vitro digestibility of crownvetch stems and leaves. First growth was sampled from flower bud to seedpod growth stage, and regrowth was sampled in July and September. Identical cutting schedules were used at four field locations in West Virginia for 2 years. Also, in growth chambers, controlled day-night temperature combinations of 16-2, 16-10, 16-18 C; 21-2, 21-10, 21-18 C; and 38-2, 38-10, and 38-18 C were used to determine temperature effects on herbage comosition. Acid detergent fiber and permanganate lignin levels in crownvetch were influenced differently by environment than were their deposition rates. High leaf ADF and lignin levels were attributed to high light intensities within the crownvetch canopy. Stem ADF averaged 18% higher and leaf ADF 36% higher in first regrowth than in second regrowth. Leaf lignin averaged 67%, higher in fist regrowth than in second regrowth. Leaf lignin levels of crownvetch under controlled temperatures and low light intensities were one-fourth to one-half of that in field samples. Maturity effects on ADF and lignin levels were significantly greater at the two locations with higher elevations. The ADF and lignin deposition rates in late spring 1970 averaged three times those in 1969 and were associated with higher rainfall. Cutin level of leaves was 65% higher than that of stems, and maximum levels were obtained either at early or full bloom stage.
In vitro digestibility of crownvetch stems decreased 0.81 percentage points per day from flower bud to early bloom, and thereafter at lower rates. Digestibility of crownvetch stems and leaves of first regrowth (58, 74%) was lower than that of second regrowth (66, 78%). The ADF and lignin levels of stems, but not of leaves, were largely independent of crop yield and were inversely related to digestibility. Prediction of nutritive value of firstcrop crownvetch is far more difficult than of other commonly used legumesPlease view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .