Developing Winter Canola as a Dual Purpose Crop for Silage and Seed Production.

Despite environmental benefits and growing demand for canola (Brassica napus L.) in the US, acreage is limited due to other higher valued crops.  Canola is traditionally harvested for seed in the Pacific Northwest, and the crop biomass is left unexploited.  If winter canola crop biomass could be harvested as forage, without dramatically decreasing seed yield, it would substantially increase the value of the crop and hence increase potential US acreage.  Currently, little research has examined forage quality of canola in the vegetative stage, but Brassicaceae crops in general are high in crude protein and energy and extremely low in fiber, so canola forage might be an attractive livestock feed, particularly for dairies.  Winter canola has traditionally been grown as a winter annual.  However, in this study winter canola is propagated as a biennial. Fodder is harvested during the first summer after a spring planting, then the crop is vernalized over winter and seed harvested the following summer.  Winter canola ‘Athena’ and an industrial rapeseed ‘Dwarf Essex’ were grown in the greenhouse and biomass was ensiled to determine forage quality.  This study confirmed high quality forage values for canola, and prompted us to examine field trials. Data collected from the 2008 field harvest using canola varieties ‘Athena’ and ‘Baldur’ showed similar excellent forage quality to the glasshouse study.  Averaged over harvest treatments we obtained: 21.1% neutral detergent fiber, 20.0% acid detergent fiber, 16.6% ash, 21.1% crude protein, and 2.9% crude fat.  Average forage yields were 0.83 ton dry matter/acre per cut or over 2.5 ton dry matter/acre over an entire growing season. Impact of biomass harvest on seed yield will be determined summer 2009.