Straw for algae control?

I was watching the Discovery Channel the other night - I believe it was
an episode of Beyond 2000 - when they were talking about algae control
in ponds. According to the program, a farmer discovered that some straw
in the pond seemed to keep the pond free of algae. It was also mentioned
that whatever it is the straw secretes seems to be beneficial to higher
life forms (plants and fishes).

I can't remember if it clears up a pond if algae is already present or
not. Does anyone else know anything about this? Sounds too good to be
true. Coming soon to a pet store near you - Tetra Straw Extract :-)

Being (unfortunately) a city person, I have no idea where to get straw
near here. My new 1 month old tank is so far thankfully algae free -
the only occupants are still the break-in mollies, one of whom just gave
me a dozen fry. But I suspect my good luck is due not so much to a well
balanced system as to too little light :-( Trying to build a hood...