Evaluating warm-season annual forages to fill summer forage gaps in short-season climates

摘要

Annual warm-season forages have been used to fill productivity and nutritional gaps during summer months throughout the southeastern United States. However, their performance and nutritive value in cooler, short-season temperate climates above 40 N has been less well studied. This study evaluated the forage mass and nutritive value of four warm-season annual forages (brown midrib [BMR] sudangrass [Sorghum bicolor ssp. Drummondii (L.) MoenchJ, buckwheat (Fagopyrum esculen-tirni Moench), Japanese millet [Echniochloa esculenta (A. Braun) H. Schol/.J, and teff [Eragrostis tef (Zuccagni) Trotter]} compared with a cool-season small grain forage, oat (Avena sativa L.), and a cool-season annual forage legume, chickling vetch (Lathyrus sativus L.). Monocultures of the six annual forage species, along with a mixture of all six species, were evaluated over 2 years in southeastern New Hampshire. Forage mass and nutritive value were assessed at weekly intervals over 3 weeks in July-August, approximately 4-to-5weeks post-germination. Across all three harvests, buckwheat, Japanese millet, and the summer mix produced greater forage mass than oat, while chickling vetch and teff produced the least. Conversely, chickling vetch had greater crude protein (CP), acid detergent fiber, and neutral detergent fiber compared with oat, while buckwheat had the lowest CP, in vitro true dry matter digestibility, and in vitro neutral detergent fiber digestibility of all the species assessed. Japanese millet produced greater forage mass while providing similar nutritive value as oat, making it a good alternative warm-season annual forage for use under cool, short growing seasons.