Crownvetch-Grass Mixtures under Frequent Cutting: Yields and Nitrogen Equivalent Values of Crownvetch Cultivars1
- Richard H. Hart,
- A. J. Thompson and
- W. E. Hungerford2
Crownvetch (Coronilla varia L.)-grass mixtures are recommended for pastures, but data were needed on forage yields under frequent severe defoliation, and on yields of crownvetch-grass mixtures vs. grass fertilized with N. ‘Penngift’, ‘Chemung’, and ‘Emerald’ crownvetch were seeded with ‘Ky-31’ tall fescue (Festuca arundinacea Schreb.), ‘Potomac’ orchardgrass (Dactylis glomerata L.) and Kentucky bluegrass (Poa pratensis L.) in 1965 in a field trial on a fine-loamy, mixed mesic Fluvaquentic Dystrochrept. Mixtures were clipped every week, 2 weeks, or 4 weeks, leaving a 5- or 10-cm stubble, in 1968 and 1969. In 1970, we removed Crownvetch from some plots with herbicide. In 1970 and 1971, we applied N at 112 or 224 kg/ha to the resulting pure grass plots, and cut all grasses and mixtures every 2 weeks. Only fescue and fescue-crownvetch mixtures were studied in 1972 and 1973. Fifty-six, 112, 168, and 224 kg N/ha were applied, and all entries were cut every 2 weeks.
In 1968 and 1969, yields of all mixtures increased as the interval between cuttings increased. Yields of all mixtures in 1968 and 1969, and of grass plus N in 1970 and 1971, were higher when cut back to 5-cm rather than 10-cm stubble height. Penngift-grass mixtures outyielded Chemung- and Emerald-grass mixtures at both stubble heights from 1968 to 1971, and at the 5-cm stubble height in 1972. Over 4 or 6 years, Penngift-grass mixtures producedm about 30% more forage than Chemung- or Emerald-grass mixtures. Bluegrass-crownvetch often outyielded orchardgrass- or fescue-crownvetch in 1968 and 1969, but total yields over 4 years of bluegrass, orchardgrass-, and fescue-crownvetch mixtures were almost the same. Fescue plus Penngift produced as much forage as fescue plus 155 and 62 kg N/ha in 1970 and 1973, respectively (mean of 5- and 10-cm stubble). Corresponding N equivalent values were 69 and 39 kg/ha for Chemung and 88 and 25 kg/ha for Emerald.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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