Inger Lamb said:

> I live in Iowa, USA, where we plant 11 million acres in
> soybeans per year, almost a third of our total area.
> I have read that some data indicate bees pollinate beans,
> and in so doing increase yields, but apparently there is
> some uncertainty about this.  Can anyone fill me in?

McGregor has a chapter on soybeans, you can read it
online:

http://bee.airoot.com/beeculture/book/chap4/soy.html

It says, in part:

  The anthers dehisce before the flower opens
  so that the stigma is in contact with and receptive
  to the pollen on the anthers. Pollination and
  fertilization is usually accomplished before the
  flower opens.

  The soybean is considered to be self-fertile and not
  benefited by insect pollination (Morse and Cartter 1937,
  Rubis 1970). Although there is no experimental evidence
  to support them, some soybean growers in Arkansas have
  indicated that bees increase production of beans, and they
  encourage the presence of apiaries near their fields.

  Tests with plants caged to exclude bees have shown no
  decrease in production over exposed plots (Woodhouse and
  Taylor 1913, Milum 1940, Piper and Morse 1910).

  Culter (1934) obtained an estimated 5 percent cross-pollination
  in open plots surrounded by 36-inch cheesecloth fences with an
  apiary nearby. Gordienko (1960) used honey bees in cages with
  two cultivars of soybeans. He fed the bees a scented sirup to
  stimulate the floral visitation and obtained 29 percent hybrids on
  one cultivar and 44 percent on the other.

I guess the bottom line is that soybeans may be an opportunity for
a honey crop, but not for a pollination fee unless the grower feels
the need for bees as "insurance".

        jim