Mixtures of kura clover with small grains or Italian ryegrass to extend the forage production season in the northern USA

Kura clover (Trifolium ambiguum M. Bieb.) has demonstrated excellent persistence in the northern USA but initiates dormancy earlier in autumn and breaks dormancy later in spring than other adapted legumes. The objective of this study was to determine if combinations of kura clover and small grains or ryegrass (Lolium multiflorum Lam.) could extend the production season for high quality forage in autumn and spring. The study was conducted from 1998 to 2000 in Arlington and Lancaster, WI. Oat (A vena sativa L.), barley (Hordeum vulgare L.), winter wheat (Triticum aestivum L.), winter rye (Secale cereale L.), and Italian ryegrass, were sown in August in monoculture and in binary mixtures with previously established kura clover. In autumn, monoculture kura clover and all mixtures had similar forage yield, but 1.5 Mg ha(-1) lower yield than monoculture oat. In spring, binary mixtures of kura clover with winter wheat or winter rye yielded 0.88 Mg ha(-1) more than monoculture kura clover. In spring, mixtures with winter wheat or winter rye contained about 60% kura clover. Binary mixtures and monoculture kura clover had 35% greater crude protein, similar in vitro true digestibility, and 32% lower neutral detergent fiber than monoculture small grains and ryegrass in autumn and spring. Oat, barley, or ryegrass sown into kura clover in autumn provide no yield advantage over monoculture kura clover. Winter small grains sown into kura clover in autumn increased forage yield in early spring, but had no impact on full-season production compared with monoculture kura clover. Ryegrass did not affect spring yield, but did increase full-season production by 15% compared with monoculture kura clover. Winter small grains and ryegrass can successfully be sown into monoculture kura clover in autumn without the use of herbicides and can increase early spring or total season forage production the following year.