Agriculture Reference
In-Depth Information
tain adequate available phosphorus levels is to have a biologically active soil. Fungi are
the main harvesters of phosphorus from the soil environment.
Most forms of phosphorus are not soluble in water, so it's mostly not found floating
around in the soil solution. It's an anion, so it can attach to positive charges on organic
matter. More often, it binds with calcium to form calcium phosphate, or with other cations
like magnesium and iron. Because phosphorus doesn't move down into the soil, it's nice
to incorporate phosphorus fertilizers into the top few inches.
A big problem is that there's not a whole lot of phosphorus left in the world. Like oil, it
has peaked, perhaps about 20 years ago. Should we be using what's left? I don't know.
Someday, we'll all have to become biodynamic gardeners so we can use the energies we
have on site and use homeopathic doses for our gardens and farms. We should start that
now.
At the same time, there are two other methods of maintaining phosphorus levels and
availability in the soil. The first is that we need to learn to make high-quality compost that
will supply phosphorus and microbes that make phosphorus available. We should even be
composting human manure to recycle that phosphorus, among other nutrients. The second
is that we need to promote mycorrhizal fungi in our soil and bacteria that specialize in
moving phosphorus. The fungi are one of the most important pieces of the puzzle in most
of our soils when it comes to getting phosphorus into the plant.
Bone meal has been a main phosphorus source of gardeners for a long time. I don't use
it anymore due to the potential of spreading the prions associated with mad cow disease.
Many ecological gardeners are still recommending it, though. Another one I use is
molasses. If a conventional soil test indicates there's a lot of phosphorus in the soil, but a
Reams test indicates there isn't enough available phosphorus, molasses can be applied to
the soil at 2/3 cup per 1,000 square feet, mixed with as much water as you need, to help
“loosen” the phosphorus.
