Yield and Species Composition of Binary Mixtures of Kura Clover with Kentucky Bluegrass, Orchardgrass, or Smooth Bromegrass

B W Kim,K A Albrecht

doi:10.5713/ajas.2008.70316

Abstract

Kura clover (Trifolium ambiguum M. Bieb.) is a rhizomatous perennial legume that has potential as a forage crop in the North-Central USA because of its excellent persistence under environmental extremes. Little information is available about defoliation effects on productivity of mixtures of kura clover with grasses typically grown in this region. Two field trials were conducted to evaluate the effects of defoliation management on yield and species composition of binary mixtures of 'Rhizo' kura clover with 'Comet' orchardgrass (Dactylis glomerata L.), 'Badger' smooth bromegrass (Bromus inermis Leyss.), 'Park' Kentucky bluegrass (Poa pratensis L.), and solo-seeded kura clover near Arlington, WI. Three harvest schedules (three, four, or five times annually) and two cutting heights (4 or 10 cm) were imposed. Infrequent defoliation and lower cutting height produced significantly greater total forage yield, 6.6, 5.8, and 5.2 Mg/ha in 3-, 4-, and 5-harvest systems, respectively; and 6.5 and 5.2 Mg/ha for the 4- and 10-cm cutting height, respectively. Averaged over 3 yr and two environments, mixtures had higher forage productions than solo kura clover (6.3, 5.7, and 6.0 Mg/ha for the Kentucky bluegrass, orchardgrass, and smooth bromegrass mixtures, respectively; compared to 5.2 Mg/ha for solo kura clover). The proportion of kura clover in mixtures increased from yr 1 to yr 2 and was constant from yr 2 to yr 3 (34, 58, and 57%, respectively). We conclude that kura clover has excellent potential as a long-term component of grass-legume mixtures regardless of the cutting height, harvest frequency or grass species, even though the proportion of kura clover in harvested forage was significantly greater with less frequent harvest and shorter cutting height of all mixtures.

Highlights

Maintaining productive grass-legume swards over a long period requires appropriate species and management practices
Orchardgrass, smooth bromegrass, and Kentucky bluegrass are commonly used in improved pastures or for hay in the North-Central USA
The primary legumes sown in pastures or for hay in this region are alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), white cover (Trifolium repens L.), and birdsfoot trefoil (Lotus corniculatus L.)

Summary

Introduction

Maintaining productive grass-legume swards over a long period requires appropriate species and management practices. The primary legumes sown in pastures or for hay in this region are alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), white cover (Trifolium repens L.), and birdsfoot trefoil (Lotus corniculatus L.). Kura clover is a deep-rooted, rhizomatous perennial legume with potential as a forage crop because of its excellent persistence under environmental extremes. It has excellent winter hardiness, is adapted to a diversity of soil conditions, tolerates frequent defoliation, and tolerates drought (Spencer et al, 1975; Taylor and Meche, 1982; Speer and Allinson, 1985; Peterson et al, 1994). Kura clover has multi-branched roots that consistently exceed 60 cm in depth, and kura clover started from rhizome segments can spread laterally in excess of 1.2 m by early in the second season of growth (Speer and Allinson, 1985)

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