ARS | Publication request: CONTEMPORARY SOYBEANS SHOW NO EVIDENCE OF YIELD INCREASES ASSOCIATED WITH PROXIMITY TO HONEY BEE COLONIES.

Submitted to: American Bee Journal
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2004
Publication Date: May 1, 2004
Citation: Danka, R.G., Villa, J.D. 2004. Contemporary soybeans show no evidence of yield increases associated with proximity to honey bee colonies [abstract].American Bee Journal. 144(5):402

Technical Abstract: Soybeans tend to be self-fertile and self-pollinating, tests during 1970-85 showed 10-15% yield increases in some cases following honey bee pollination. We investigated whether honey bee activity on more recently bred soybean cultivars (both conventional and transgenic) increases bean yield. Apiaries were located adjacent to seven commercial soybean fields during bloom and bean yield was measured at various distances from the colonies. The fields in Mississippi and Louisiana varied in many ways that might affect yield, e.g., irrigation, cultivars, bee colony densities, and weather during bloom. Yields were based either on measurements of 15 samples at each distance (with each sample comprising all plants in 10 feet of row) (for two fields) or from a 1-acre plot mechanically harvested at each distance (for five fields). A positive relationship did not occur between proximity to an apiary and soybean yield in any of the seven fields. Yields ranged from ca. 20 to 63 bushels per acre in each field. Densities of honey bee foragers relative to apiary locations were measured in 2001 in two Louisiana fields by counting bees and flowers in 25-m sections of rows during mid day on multiple days during bloom (late June to early August). Forager densities varied greatly between the two fields. However, the field with almost no bee activity (max of 0.05 bees per 1000 flowers) had greater yield (53 bu/acre) than the field with much greater activity (up to 0.8 bees per 1000 flowers; 38 bu/acre). Overall, the tests provide no evidence that yields of contemporary soybean cultivars benefit from increased foraging activity by honey bees during bloom.