Investigating ways to improve native pollinator floral resources by comparing multipurpose cover crops of Phacelia, buckwheat, and a commercial bee forage mix
In the Northeast, fruit crops and many vegetable crops depend on insect pollinators for optimal fruit set and yield. The honeybee and native pollinator population declines that we are experiencing have the potential to significantly reduce fruit and vegetable crop yields. Cover crops are traditionally used to build soil organic matter, prevent erosion, suppress weeds, and scavenge nitrogen. Another category that should be added to this multipurpose list is that of pollinator and beneficial insect floral resource.
To evaluate Phacelia’s attributes and to learn more about buckwheat and a bee forage mix, we made two plantings during the 2013 growing season, -June 5 and August 7. Each planting had 3 replicates of each cover crop for a total of 9 plots. Individual plots were be 240 square feet (12’x20′) set up in a
randomized complete block design. We blocked to account for different weed populations and to keep time of day and weather during data collection similar (one block at a time). We want to carry this research over into a second year to determine the potential for self-seeding in these plots and to further evaluate weed suppression.
Native pollinator populations were observed by setting up a permanent 3 square foot quadrangle in each plot and observing each quadrangle for 5 minutes on a weekly basis or as soon as the weather permitted (above 55 degrees, no rain). Other beneficials such as parasitic wasps, lacewings, ladybugs and pests such as tarnished plant bug were sampled by 20 sweeps of a standard sweep net/plot after the pollinator observation work was done.
Flowering phenology was be observed weekly and estimated as a percentage of buds flowering. Flowering phenology of our different cultivated fruit species was also noted to determine the potential for pollinators being pulled away from the fruit.
Weed and desired plant densities were counted in the 3 square foot sampling site for each plot 3-4 weeks after planting.
We were able to establish two successful buckwheat and phacelia plantings. Due to weed pressure, the commercial bee forage mix was not as successful. Honey bee and native bee populations were plentiful and data was collected as planned on pollinator visits. Tarnished plant bug populations were also monitored and were plentiful.
Impacts and Contributions/Outcomes
Our data sets will be further analyzed this winter. Since we missed our planned early planting this spring due to wet weather, we will try to get a spring planting done in 2014 to learn about cool weather germination of our cover crops. Since our commercial bee forage mix didn’t establish well, we will try a stale seedbed technique this coming year.
University of Vermont Extension
278 South Main Street, Suite 2
Saint Albans, VT 05478
Office Phone: 8025246501