Agriculture Reference
In-Depth Information
values of selected organic fertilizers.
Algae.
Algae are incredibly diverse, from giant kelps along ocean coastlines
to one-celled organisms floating in a pond. Perhaps the most diverse are the
blue-green algae (also called cyanobacteria) that are found almost every-
where life exists, as free-floating blooms, strands, and sheets in lakes and
rivers to the symbiotes living inside lichens on desert rocks. For growers, the
primary benefits of algae are as sources of plant nutrients.
One problem with using algae is that most algae has little dry matter and
is primarily water, making harvesting and processing very labor intensive.
You can harvest sheets, strands, and balls of algae from a farm pond and
dump the materials around your fruit trees. You may also choose to wait un-
til the pond has dried and scrape off the surface crust and algal remains to
apply as a soil amendment. For a very small orchard, this approach might
yield some benefits, depending on the soil conditions. You will add very little
organic matter, and the primary benefit will be the addition of micronutri-
ents. Any microorganisms you add will be adapted to watery environments
— certainly not what you want in an orchard soil.
Probably most useful to organic orchardists are kelps (brown algae),
when used in small quantities and as commercially available products. If you
live close to kelp forests along a coastline, you might economically obtain
large enough quantities to use as a source of nitrogen and other macronu-
trients. However, the energy and labor required to harvest the material and
process it into a form suitable for orchard applications would make kelp a
very expensive option for most growers. When using large quantities of kelp,
be aware that it contains large quantities of sodium that can damage orch-
ard soils by displacing calcium, phosphorus, and other plant nutrients from
the soil and organic matter particles. Commercially available kelp meals and
extracts are available and can serve as good sources of micronutrients, de-
pending on how the kelp was processed. Some blue-green algae products
