Effects of Cutting Schedule on Quality and Yield of ‘Higher Quality’ Alfalfa Cultivars in a Mediterranean Environment

Producing high yields of dairy-quality alfalfa (Medicago sativa) hay is largely hindered by the increased levels of lignin and low fiber digestibility as the crop matures. Specific higher quality varieties tested here have the potential to increase yields unhindered by the penalty in quality that typically occurs with late maturity. Studies were conducted in Davis and Parlier, CA in 2017-2019 in irrigated trials using a split-plot design with harvest schedules as main plots and varieties as sub-plots utilizing semi- dormant (Fall Dormancy 6) and non-dormant (FD 8-9) lines. Long cutting intervals (37 to 40 d) resulted in significantly higher yields than a ‘normal’ schedule (28-29 d), indicating the yield reward for delayed cuttings. Higher quality varieties harvested under a longer cutting interval yielded 13 to 15% higher and had similar NDFD levels to conventional varieties cut under a normal cutting schedule. The results from this study demonstrate the potential of new higher quality alfalfa varieties in a Mediterranean environment as a potential tool for delaying harvests, increasing yields, while maintaining high digestibility (NDFD) without the dramatic increase in fiber and lower digestibility that typically accompanies late harvests