Gardening Articles for week ending
6th OCTOBER 2007
Written by Wally Richards.
What is the Value of Phosphate for plants?
Phosphorus is the third most limiting nutrient with respect
to macro nutrient uptake. Nitrogen and potassium are the only
other two essential plant food nutrients taken up in greater
quantities than all other minerals and elements. The potential
and occurrence of phosphorus deficiency is second only to
Phosphorus plays a vital role in energy transfer, photosynthesis,
nutrient transport, sugar metabolism, plant genetics, cell
division and as a structural component of plants.
Crops with adequate phosphorus show steady vigorous growth
and earlier maturity. Earlier maturing crops are less susceptible
to summer drought, disease infection, frost and harvest damage.
Plants absorb soil solution phosphorus in both the H2PO4-1
and HPO4-2 forms.
Phosphate has an interesting history and in the distant past
this vital plant nutrient was obtained by collecting bat or
bird dung (gunga) from large deposits on Islands around the
planet, and moved in the good old sailing ships of the time.
Towards the end of the 1800s in England it was found
that phosphorus could be obtained by treating bones with sulphuric
The other natural source of phosphorus is obtained from RPR
(reactive phosphate rock) but if we take RPR and grind it
down to a fine powder and apply it to our soil it can take
many years of microbial activity to release the phosphorus
to make it available to the plants. (Similarly with limestone
which takes 3 to 10 years to become available, where a soft
lime such as Rapid Lime is readily available.)
Thus RPR is a waste of time when applied to the soil in its
pure form. A mechanism had to be devised to make the phosphorus
immediately available. It was soon realised that if sulphuric
acid was able to make phosphorus readily available from bones
then the same acid should work on RPR.
It did and a new word came into our agriculture, namely superphosphate.
There are two basic types of super; To make 0-20-0, rock phosphate
is treated with sulphuric acid to make calcium phosphate (0-20-0)
and calcium sulphate (gypsum).
To make 0-46-0, rock phosphate is treated with phosphoric
acid. With this, much higher phosphate content, much higher
N-P-K fertilizer formulas can be made. Less needs to be used.
And it sells for a higher price with much better profits for
A retired fertiliser manufacture once explained that, when
used, superphosphate is laying naked in the soil and looking
for something to marry up with. It bonds up with zinc, iron
and manganese, then the plants cant assimilate them.
It is a truth that the fertiliser companies like to keep secret.
The conversion process of making super phosphate (Super) is
a very dirty, polluting industry which has contaminated vast
areas of land where super is made. Fluoride gasses are created
during the manufacture of chemical fertilisers and to prevent
the pollution of these chemical gasses to the surrounding
country side scrubbers are used.
After being captured in the scrubbers, the fluoride acid (hydrofluorosilicic
acid), which is a classified hazardous waste, is barreled
up and sold, unrefined, to communities across the country.
Communities add hydrofluorosilicic acid to their water supplies
as the primary fluoride chemical for water fluoridation. As
one environmentalist said: '"If this stuff gets out into
the air, it's a pollutant; if it gets into the river, it's
a pollutant; if it gets into the lake it's a pollutant; but
if it goes right into your drinking water system, it's not
a pollutant. That's amazing... There's got to be a better
way to manage this stuff" (Hirzy 2000).
Super harms the soil life and locks up other plant nutrients
which overall results in both pest and diseases problems in
our gardens and food chain.
Some years back a company in New Zealand developed a method
of using microbes to break down RPR naturally so when applied
to the soil it would be readily available to the plants. The
product is called BioPhos and is organically certified. Recently
the fertiliser company Balance purchased the production
rights of BioPhos and are marketing the product to farmers
and horticulturists as a natural alternative to super.
This is very interesting as a number of farmers/horticulturists
are becoming aware of the harm conventional fertilisers are
doing to their land, stock and crops. They are looking for
better alternatives, this is great for the environment and
our food chain. (Slowly people are starting to wake up to
the damage that has been happening over the last 50 plus years)
BioPhos is available through garden centres for your use as
an alternative to super.
BioPhos contains phosphate, potassium, sulphur and calcium
at the rates of P10:K8:S7:Ca28.
The lumps or granules actually contain 4,888,000 fungal colonies
to aid the breakdown and enhance your garden soils. Thus you
not only are adding the needed phosphorus to you garden soils
but also additional microbes which are going to work for you,
making for better soils and plants.
BioPhos is pH neutral and is used at the following rates;
New beds work in 100 grams per square metre, the same with
lawns but water in to settle.
Side dressing plants; seedlings 8 grams (a teaspoon full)
around base of the plant or in the planting hole. Same for
potatoes (which do well with phosphorus) Sowing beans peas
etc sprinkle down row with seeds. Roses and similar sized
plants 18 grams or a tablespoon full around plant or in planting
Established fruit trees etc, spread at the rate of 100 grams
per square metre around drip line or where feeder roots are.
Apply to vegetable gardens in spring and a further application
in autumn if growing winter crops. Can be applied to container
plants also. Apply to tomatoes when planting or side dress
BioPhos need only be applied once a year or a little with
each new planting whether it be vegetables or flowering plants/ornamentals.
When you apply natural products to your soils you are gardening
the soil, building up the soil food web which is the key to
healthy plants and food crops.
When you apply harmful chemical fertilisers and sprays you
are creating the problems that are so commonly seen in many
Beneficial natural products include, Mycorrcin (feeds the
soil life) Magic Botanic Liquid MBL (which releases the nutrients
that have been locked up in the soil, along with many other
Ocean Solids (provides all the natural minerals and elements
from the blue waters of the ocean)
Simalith (Basalt rock dust also providing minerals along with
silica to aid the natural electricity in the soil)
Then we have the goodies such as animal manures, sheep pellets,
blood & bone, sea weed formulations, compost, Rapid Lime,
Dolomite, Gypsum, etc.
Every week I have gardeners that contact me to say that they
have read these columns and followed my suggestions. They
thank me, as their gardens and plants have never been healthier
It is only common sense.
Any Problems ring me at 0800 466464 (Palmerston North 3570606)
Web site www.gardenews.co.nz