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<pre>My last independent soil test revelealed a slight Boron deficiency.
Based on the recommendations in the report I calculated that the
amount of Borax my soil required was 5 g per sqaure metre.

I seem to remember the last time I flicked through the Olive
Production Manual they were recommending adding 500 g per tree in
similar circumstances. I think I also read the same figure in a
report from a group of growers in the Hunter Valley in here in
Australia.

500g seems like a hell of a lot of Borax. I was under the
impression that Boron has a very small range between effectiveness
and toxicity.

At the same time I do want to make an meaningful difference to my
soil Boron levels as my trees do drift in an out of Boron deficiency
when I do a leaf test. I have used Solubor foliar sprays as a short
term remedy.

Cheers,


Steven Chaffer
Kaoota Tasmania
</pre>
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<pre>> My last independent soil test revelealed a slight Boron deficiency.
> Based on the recommendations in the report I calculated that the
> amount of Borax my soil required was 5 g per sqaure metre.
>
> I seem to remember the last time I flicked through the Olive
> Production Manual they were recommending adding 500 g per tree in
> similar circumstances. I think I also read the same figure in a
> report from a group of growers in the Hunter Valley in here in
> Australia.
>
> 500g seems like a hell of a lot of Borax. I was under the
> impression that Boron has a very small range between effectiveness
> and toxicity.
>
> At the same time I do want to make an meaningful difference to my
> soil Boron levels as my trees do drift in an out of Boron deficiency
> when I do a leaf test. I have used Solubor foliar sprays as a short
> term remedy.

Hi Steven,

I was probably one of the Hunter Valley group looking at Boron deficiency.
It was well known in the local vineyards that the local soils are boron
deficient, and we have found the same sort of thing with olives. Boron is
deficient below 19 ppm and excessive / toxic over about 185ppm (from
memory - please check these figures) so there is a fairly wide range, but
I've never heard of borax toxicity in Australia. I normally aim for around
40 - 60 ppm from a leaf test. Beware the residual boron traces after a
foliar spray, as this will seriously distort the figures. It can take a full
year for all the spray to be absorbed or wash off (especially with our lack
of rainfall).

The two chemicals - Borax and Solubor - work differently. Borax as a dry
powder is thrown around under the trees and takes a while to work its way
into the soil and down to the roots, especially here in clay-loam soils. We
put on 500g per tree to give it about a 5 year supply, as the tree will take
up what it wants if it is used this way.

Solubor / Bortrac are foliar sprays and are absorbed directly and very
quickly into the tree and used up fairly quickly. Ideal for a "top-up" just
before flowering but not really a remedy for boron deficient soils.

Depending on the usual variables : soil type and the ability of borax to
move through to the root zone; age and size of trees; tree spacing;
irrigation system; rainfall; availability of chemicals; budget etc there are
a whole host of options, but I'd be inclined to have a chat to a local
agronomist / soil specialist before doing anything further. $100 spent
talking to somebody with relevant experience will be quickly re-couped in
not wasting chemicals and time.

Regards,

Mike Wilson
Hunter Valley.
</pre>
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<pre>Mike wrote

I was probably one of the Hunter Valley group looking at Boron deficiency.
It was well known in the local vineyards that the local soils are boron
deficient, and we have found the same sort of thing with olives. Boron is
deficient below 19 ppm and excessive / toxic over about 185ppm (from
memory - please check these figures) so there is a fairly wide range, but
I've never heard of borax toxicity in Australia. I normally aim for around
40 - 60 ppm from a leaf test. Beware the residual boron traces after a
foliar spray, as this will seriously distort the figures. It can take a full
year for all the spray to be absorbed or wash off (especially with our lack
of rainfall).

Don't forget that there is a lot of Boron (25-50ppm) in the olive waste
after processing and that this has to be replaced before the next season.

Best regards
Peter Caird
www.victorianolivegroves.com
0418 392 157
61 3 5441 5388



[Non-text portions of this message have been removed]
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<pre>> The rates of Boron mentioned from the information I have appear extreme.
> Soil level of Boron for olives should be between 2 and 3 ppm. Basically
> that's 3 kg of actual Boron per hectare. A very narrow range indeed and
> foliar levels between 30 and 100.
> Variations is sample results are common because of seasonal fluctuations
of
> born levels due to demand i.e fruit and flowering. Soil assessment can be
> very hit and miss because of the small amounts in the soil and previous
> applications.
> Boron toxicity can be disastrous when excessive Boron is applied as it
takes
> years for the boron to deplete. Trees can have minor symptoms expressed
but
> have serious infertility issues resulting in low yield. Always apply
boron
> with care as reapplication is always better that boron toxicity.
> Foliar application can be safer than soil application as the rate applied
is
> very low and can be distributed more evenly across the area. Uneven
> application can result in toxicity in localised areas.
> 500 grams per trees is about 120 to 150 kg per hectare. 40 to 50 kg
actual
> boron depending on product. Bulk phosphate fertilisers are applied at
this
> rate not trace elements. I generally recommend chelated boron at very low
> rates applied as a foliar pre-flowering and mid season. We often have to
> apply foliar products for pests and disease, so why not combine specific
> nutrients if required to save time.
>
> I hope I haven't opened a can of worms, but the more we throw ideas and
> knowledge around the more we'll learn.
>
> Cheers
> Russell March
> B. Ag. Sc.
> Agronomist & Technical Sales Consultant.
>

Russell,

Is the uptake of boron from the soil affected by pH; soil type (clay /
sandy, etc); ground cover or the amount of available water? I was using
Borax which was about (from memory) 30% boron, spread widely over the root
zone. The trees are mulched with sugar cane mulch and irrigated with 35L/hr
sprays, the soil is a medium clay loam with a pH of about 5.5/6 and we have
famously dry winters so the soil was bone dry other than from the
irrigation.

Regards,

Mike Wilson.
Hunter Valley.
</pre>
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<pre>Thanks for all that.

I guess after reading all that I'll stick pretty much to what I have
been doing. That is spreading small amounts of micronutrients around
the trees (only 5-10 g Borax per tree!) in response to the soil
analyses and then using a foliar spray pre flowering if needed.

Thanks for the discussion.

Steven Chaffer
</pre>
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<pre>> G'day Mike
> Sorry I didn't reply quickly, I've been at field days for a couple of
days.
> Yes the soil pH, texture and water content do have effects on Boron in the
> soil. Calcium levels are in general relative to pH. There are variations
> relating to exchangeable cation ratios of Potassium, Sodium and Magnesium
> but just keeping it simple Boron and Calcium are closely related, and as
you
> know, have a very important role in Olive production. Boron will bind to
> the soil and takes a long time to be used by plants. It is very immobile
> but can be move through the profile with enough water. Soil texture
changes
> the level of boron required to cause toxicity. If the boron is highly
bound
> i.e. clay soil and the clay soil has a high nutrient capacity, much higher
> levels of boron can be found in this soil with little effect on the plants
> compared to a lighter sandy soil. Improving calcium levels in the soil is
> always important when dealing with boron because of the interaction
between
> the 2.
>
> I could rattle on for hours about nutrient interactions but I just tend to
> get complicated. Mulders exchange chart is a good guide to assess basic
> interactions of nutrients. Soil chemistry of each element helps us
> understand the exchangeability or activity of individual nutrients. But
the
> most difficult part to follow is the interactions and chemistry of
> combinations of nutrients within the plant. Specifically transport
methods.
>
> I always follow a procedure of steps when addressing soil conditions for
> Olives and stone fruit crops.
> REPARATION
> Firstly pH (Soil interactions are based on chemical natures and require
> specific soil pH levels to interact in a balanced manner)
> Hence calcium, Potassium sodium and magnesium ratios (relative to soil
> texture.)
> Phosphorous, Nitrogen
> Finally trace element levels
> MAINTENANCE
> Specific application of macro and trace elements with specific timing
based
> on growth stage.
>
> This is never set in concrete as specific nutrient deficiencies or
> toxicities may be so significant that they require immediate attention.
>
> I hope what I've written is understandable, discussion of ideas and
> experience can help.
>
> Cheers
> Russell March

Thanks Russell, that is a weight off my mind. I had used the aforementioned
quite heavy rates of Borax on clay soils and was stressing about possible
toxicity, but it seems that I should be okay given that the soil is a fairly
hydrophobic clay and does not tend to take in rainwater all that well unless
we get a week of gentle soaking rain, and that happens quite rarely.
Normally we get the short, sharp dump (and associated run-off, erosion, etc)
and than have to rely on irrigation to actually get moisture down to the
root zone - normally 35 litre an hour sprays, but some drips.

We have added Calcium in the form of powdered gypsum, with the odd backup
spray of liquid lime & gypsum but this program is being looked at to improve
the effectiveness.

You mention "Mulders exchange chart" which I take it is a guide to mineral
uptake? Do you know where I can find such a chart?

Regards,

Mike Wilson.
</pre>
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<pre>All great stuff and so true, Russell - a well constructed explanation. Just
don't forget to work with the soil biology as well. It is at least a third
of the total soil fertility.

Best regards,

Gerhard
-----Original Message-----
From: OliveOil@yahoogroups.com [mailto:OliveOil@yahoogroups.com] On Behalf
Of Mike Wilson
Sent: Friday, 16 September 2005 3:35 PM
To: OliveOil@yahoogroups.com
Subject: Re: [OliveOil] Boron deficiency

> G'day Mike
> Sorry I didn't reply quickly, I've been at field days for a couple of
days.
> Yes the soil pH, texture and water content do have effects on Boron in the
> soil. Calcium levels are in general relative to pH. There are variations
> relating to exchangeable cation ratios of Potassium, Sodium and Magnesium
> but just keeping it simple Boron and Calcium are closely related, and as
you
> know, have a very important role in Olive production. Boron will bind to
> the soil and takes a long time to be used by plants. It is very immobile
> but can be move through the profile with enough water. Soil texture
changes
> the level of boron required to cause toxicity. If the boron is highly
bound
> i.e. clay soil and the clay soil has a high nutrient capacity, much higher
> levels of boron can be found in this soil with little effect on the plants
> compared to a lighter sandy soil. Improving calcium levels in the soil is
> always important when dealing with boron because of the interaction
between
> the 2.
>
> I could rattle on for hours about nutrient interactions but I just tend to
> get complicated. Mulders exchange chart is a good guide to assess basic
> interactions of nutrients. Soil chemistry of each element helps us
> understand the exchangeability or activity of individual nutrients. But
the
> most difficult part to follow is the interactions and chemistry of
> combinations of nutrients within the plant. Specifically transport
methods.
>
> I always follow a procedure of steps when addressing soil conditions for
> Olives and stone fruit crops.
> REPARATION
> Firstly pH (Soil interactions are based on chemical natures and require
> specific soil pH levels to interact in a balanced manner)
> Hence calcium, Potassium sodium and magnesium ratios (relative to soil
> texture.)
> Phosphorous, Nitrogen
> Finally trace element levels
> MAINTENANCE
> Specific application of macro and trace elements with specific timing
based
> on growth stage.
>
> This is never set in concrete as specific nutrient deficiencies or
> toxicities may be so significant that they require immediate attention.
>
> I hope what I've written is understandable, discussion of ideas and
> experience can help.
>
> Cheers
> Russell March

Thanks Russell, that is a weight off my mind. I had used the aforementioned
quite heavy rates of Borax on clay soils and was stressing about possible
toxicity, but it seems that I should be okay given that the soil is a fairly
hydrophobic clay and does not tend to take in rainwater all that well unless
we get a week of gentle soaking rain, and that happens quite rarely.
Normally we get the short, sharp dump (and associated run-off, erosion, etc)
and than have to rely on irrigation to actually get moisture down to the
root zone - normally 35 litre an hour sprays, but some drips.

We have added Calcium in the form of powdered gypsum, with the odd backup
spray of liquid lime & gypsum but this program is being looked at to improve
the effectiveness.

You mention "Mulders exchange chart" which I take it is a guide to mineral
uptake? Do you know where I can find such a chart?

Regards,

Mike Wilson.








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</pre>
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