Ian;
P and K are not micro nutrients. Plants (and animals) require these nutrient
elements in larger quantities. As these elements are already in your soils
(in all likelihood), your biological additions should make these more
accessible to your plants over a period of time. I.e.: Once your soils are
biologically more active. Chicken manure is a source you could consider, but
if you're a composter, then you should be composting it, or composting it
and using it in your worm bins. The other products can be added to compost
too but many of them can for ease of work be added straight to the field.
For example soft rock phosphate, although more soluble that rock phosphate,
is still not very soluble. So you would need a large quantity and adding it
to your compost would make your turner work so much harder for little added
benefit. Feather meal, bone meal, blood meal, fish waste products are good
sources of phosphates but are too expensive for broad scale farming unless
you're organic. Cotton seed and soya oilcakes are way too expensive, and
are best fed to your livestock (Assuming you have) rather than tossed on the
soil or compost heap - unless you are making compost to be used as ACT where
it may have a place.
Lime is a slow working amendment and is dependent on microbial action as
well as acidic conditions for release. Gypsum is a better calcium source
given its solubility, but has no effect on pH if your soils require that
correction. It's usually used in soils that have higher pH. The reason it
has no effect on pH is because it contains lots of Sulphur. So if your soils
are low in S and Ca, then it's a good choice. Also if you have a high Na
problem, it will help to correct that.
Phosphates at planting to bind sandy soil is a new one on me. Maybe you mean
Magnesium. Magnesium should only be added to soils if you need them as they
tighten your soils and make working them more difficult.
Potassium is good during the season if your plant assay shows your plants to
be deficient. Then a foliar application is very effective. Especially if you
have high Na as the Na and K (Potassium) ions are of similar size (adjacent
on the periodic table) and plants tend to take up Na instead of K even in
high testing K soils if Na is high.
As you can see, the subject is rather more complex than imagined at first
blush. Giving blanket recommendations based on the vague information you
have supplied would more than likely cause more confusion than anything
else. Your best bet is to use the services of an agronomist or plant
scientist to apply required amendments and then to discuss your biological
ideas with them. There must be lots in Zim, or in SA.
SS
From: compost_tea_at_yahoogroups.com [mailto:compost_tea_at_yahoogroups.com] On
Behalf Of RTS Friction - Carruthers
Sent: 02 June 2011 13:49
To: ECO Compost tea
Subject: [compost_tea] When to add ammendments to the soil
Hi all this is slightly off group topic but in the range of what we
generally try to emulate, there are so many well educated folk on this group
so am taking the opportunity to glean some of your experiences.
As most of us know, similarly to compost, vermicast is lacking in phosphates
& potassium (important additions required for optimum plant growth). For
gardening when is the best time to add these trace elements. I'm referring
to amendments such as blood & bone meal, dry fish, rock phosphate, ash,
chicken manure, feather meal, cotton seed & Soya cake etc.
1) Include steadily in the worm feed from the start
2) Mix into the VC prior to use/application
3) Mix in directly to the soil before VC application (how long before
planting)
4) Or apply weekly in the watering/top dressing
At present I lime directly two weeks before planting, am led to believe lime
additions directly to Compost can lead to Ammonia (N) losses. Presume this
would have the same effect in VC, unless of course the pH is low and
adjustments need to be made. I add phosphates at planting to bind my sandy
soil and reduce N losses.
I add potassium half way through the growing period to boost flowering &
fruiting. Am I on the right track?
The conclusive answers to these questions I've failed to find on the net,
look forward to any advice on this.
Thanks
Ian C
Received on Sat Jun 04 2011 - 13:55:05 EDT