Enhancing Floral Resources for Insect Pollinators Utilizing White and Alsike Clover in Alfalfa Hay Fields.

A decline in honeybee and native bee populations in the Northeast U.S. over the past few decades has been attributed to many factors including mites, disease, pesticide exposure, and a loss of nectar and pollen resources.  Historically, an important food resource in Vermont has been from forage legumes in hay and pasture.  This resource has declined over the past two to three decades due in part to a decline in acreage of legume hay crops, and an increase in intensity of harvest by dairy farmers in order to optimize feed quality, thus, resulting in very little bloom periods.  Our objective was to test the feasibility of improving mid to late nectar production by growing mixtures of clovers with alfalfa managed for hay.  The hypothesis was that white clover and/or alsike clover would initiate bloom during regrowth and sustain a bloom until the stand was cut, without negatively affecting forage yield or quality.  A study was conducted at two locations in the Champlain Valley evaluating floral production of two cultivars of white clover (‘Pinnacle’ and ‘Crusade’) and a common cultivar of alsike clover, all grown in combination with alfalfa managed for hay in a four cut system.  White clover was much more prolific at producing flowers compared to alsike clover.  Generally, white clover would produce bloom within the first week to 10 days after regrowth and would continue to bloom until the next harvest.  ‘Pinnacle’ white clover had the most abundant flowers and the most widely distributed throughout the season.  Yield and quality were not negatively affected when clover was seeded at 3 or less kg/ha.  There was a significant decline in clover flowers in the second and third year of the study indicating year to year variation that may affect the utility of these methods to enhance insect pollinators.