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Re: Harvesting exotics
> Date: Fri, 24 Jul 1998 11:27:40 -0500
> From: "David W. Webb" <dwebb at ti_com>
>
> That's an interesting question. I wonder how many of the exotics that we
> (collective humanity) have introduced could have application as fodder for
> certain types of animals. This could be an interesting study and one that
> might pay for aquatic harvesting. After all, Hydrilla is known to grow
> upwards of 3" per day in direct sunlight. This is a pretty good ratio when
> you consider the cost of livestock feed. I have a feeling that the
> nutrient value is somewhat less than grain, but it might still be good
> enough for filler during those expensive summer months. Have there been
> any studies in regards to the applicability of aquatic plants for livestock
> fodder?
The big problem is that while aquatic plants are very high in protein
on a dry weight basis, they are very low in dry weight. It's uneconomic
to haul them to the animals, but if you don't do the feeding well away
from the body of water, the nutrients get washed back in from the manure,
which may or may not be the opposite of what you want. It's also very
labor- and/or energy-intensive to get the plants out of the water.
The Chinese have a pond polyculture based on carp, ducks and rabbits, using
water spinach (Ipomoea aquatica), a marginal plant, as rabbit feed. Some
work has been done in Florida on using water hyacinth to produce a garden
compost to replace peat moss, but the economics are iffy, because you have
to dry the plants or dilute them with a lot of dry low nitrogen material or
you get a stinking mess. Drying the plants isn't easy either - you either need
a lot of space to spread them out or a lot of labour and/or energy to turn the
windrows in a smaller area, or you get a stinking mess. A dry climate is
helpful too. You would even need to dry them to make silage.
There's a county in central Florida which has a naturalized (feral) population
of Cryptocoryne wendtii. Maybe some enterprising soul should go in there
and harvest the stuff to sell us?