PSVIII-32 Improving qualilty of alfalfa-grass mixtures.

摘要

Our goal was to improve the forage quality of alfalfa-grass mixtures. Four alfalfa varieties (HarvXtra, LegenDairy XHD, Hi-Gest 360, and Pioneer 55H94) were sown in binary mixtures with 5 perennial grasses (Bariane tall fescue, Fojtan festulolium, Driftless meadow fescue, Dividend VL orchardgrass, and sparse-heading orchardgrass) at two sites in NY in 2016.These trials were harvested three times in 2017. Also, three low-lignin alfalfas (HarvXtra, Hi-Gest 360, and KF425HD) were sown in binary mixtures in 2017 with seven grasses (Bariane tall fescue, Tetrax, Pradel and Preval meadow fescue, Dividend VL orchardgrass, Chiefton reed canarygrass, and Sunset III timothy). This seeding year study was harvested twice in 2017. All studies had six field replications. Alfalfa and grass were hand-separated for every plot and analyzed separately for CP, NDF, IVTD, NDFD, ADF and lignin. Across all of our alfalfa-grass studies across NY in 2017, HarvXtra averaged 5.3% higher in NDFD than other alfalfa varieties. Meadow fescue was consistently higher in fiber digestibility than other grasses in 2017. Crude protein content of mixtures was considered adequate across the range of grass percentages in mixtures. The combination of reduced-lignin alfalfa with meadow fescue can result in a large increase in forage NDFD. On average in 2017, including HarvXtra and meadow fescue in a mixture would increase forage NDFD by 6%, assuming a mixture that is 30% grass. In a 30% grass mixture, the addition of meadow fescue increases NDFD of the mixture by approximately the same amount as adding HarvXtra to the mixture. While essentially every seed company is promoting alfalfa varieties claiming higher quality, it is clear that switching to meadow fescue in mixtures may have more impact on forage quality than switching to most of the high quality alfalfa varieties available.