Interaction Between Harvest Frequency and Variety Maturity On Yield and Quality of Orchardgrass.

Management of forages must be planned to optimize production of feed to ensure whole-farm nutrient efficiency. Dairy cattle diets in coastal BC comprise of home-grown grass and corn silage, and imported concentrates rich in energy and rumen-bypass protein. BC dairy farmers maximize the nutritional quality of grass crops by providing ample nutrients and frequent cutting. Early maturing varieties are often used to allow an early first cut to maximize yield. However, the effect of frequent cutting and grass maturity on crop yield and quality has not been examined despite the importance of home-grown feed production in this land-limited region. The hypothesis of this 3-year orchardgrass experiment was that reducing the frequency of cutting (from 5 to 3 times year^-1) would increase yield and that the decline in quality would be mitigated with the use of a late maturing variety. The medium (Chilliwack) and late (Haida) varieties flowered about 6 and 10 days, respectively, later than the early variety (Cheam). Reducing harvest frequency from 5 to 3 cuts increased yield and in vitro digestible dry matter (IVDDM) by 2.8 t and 1.5 t ha^-1, respectively, for the late variety compared to only 0.9 and -0.1 t ha^-1, respectively, for the early variety. The medium maturing variety was intermediate. The 3-cut late variety treatment (novel) increased IVDDM over the 5-cut early variety treatment (conventional) by 0.7 t ha^-1 and yield by 1.6 t ha^-1. There was a decline in quality parameters with the novel treatment but little effect on NDF digestibility. The effect of the novel orchardgrass management system on balancing dairy rations and farm nutrient sustainability will be discussed.