On Fri, 7 Mar 2003 21:37:25 +0000 (UTC), (Victor
M. Martinez) wrote:
Joe Doe wrote:
precipitate. If you do suceed in moving the pH to neutrality with sulfur
more phosphate becomes available but it is unlikely to ever really

You can't really change the pH of our soils to neutral for long.

I had a series of soil tests done on my yard when I first bought my
home. The results showed I had 9,000 pounds of "excess" calcium per
acre in the top 6 inches. To convert the excess calcium to calcium
sulphate or calcium phosphate would take roughly the same weight of
sulphur or phosphorus. And that is just for the top six inches.

LCRA completed a study several years ago looking at the subsurface
migration of phosporus from a septic tank leach field. It did not
occur due to the reaction with calcium - the phosphorus was
precipitated immediately and was no longer soluable.

What is a problem here and Victoria has something posted about it here
is the weed and feed products. There was an ad in the paper the other
day which included 7 different lawn fertilizer products. Only one of
these did not have herbicides in it. Some of the bags had big
Atrazine labels. Every bag, however, was label "Put the contents of
this bag on 5,000 square feet (or so)". No mention of weight of
contents of the bag. State law makes them put the numbers on the bags
for N-P-K content since it is a fertilizer, an agricultural product.

Soil nutrient chemistry is a lot more interesting and fun that that.

Rusty (on a soapbox) Mase

Rusty Mase wrote:
What is a problem here and Victoria has something posted about it here
is the weed and feed products. There was an ad in the paper the other

Agreed. However, I would thing that folks that go through the trouble of
reading a forum like this one, or listen to the radio shows on the weekend
or watch CTG on PBS really are not going to go and buy these products.
Ok, raise your hands those of use who use these things?
Anybody?

Soil nutrient chemistry is a lot more interesting and fun that that.

Indeed! We just planted our 4-inch tomatoes into temporary 1-gallon pots
using Vortex soil, some organic fertilizer, some mineral mix, and dry
molasses. We then watered them with seaweed solution. We'll see how they
do. This is the first time we've started tomatoes this way (we also have
some seeds in 4-inch pots).

--
Victor M. Martinez

http://www.che.utexas.edu/~martiv

On Sat, 8 Mar 2003 14:07:39 +0000 (UTC), (Victor M.
Martinez) wrote:


Agreed. However, I would thing that folks that go through the trouble of
reading a forum like this one, or listen to the radio shows on the weekend
or watch CTG on PBS really are not going to go and buy these products.
Ok, raise your hands those of use who use these things?
Anybody?


My garden is most likely going to be filmed for Central Texas Gardener in June
of this year. I have to determine when I feel it's at peak. I was floored when
the offer was made. I'm so excited I can hardly believe it.

Here is a link to some photo's at times during the growing season.

http://home.austin.rr.com/animaux/ne...n/Page_1x.html


This little website (I'm computer illiterate) was thrown together so my mother
could see the gardens. I do plan to fix it and make it more informative. I'm
also writing a book with a working title of "When North Moves South."

I find the most exasperating problem is when people move from piney, moist
forests with 50 inches of rain and up, in acidic soils with available nutrients,
then try to garden in our soils which are the complete opposite.

I will only be writing about my experiences, not making any claims to be a pro
or expert, just a simple gardener, as H.H. The Dalai Lama always says, he's just
a simple monk! I think he is much more humble than I

Victoria

animaux wrote:
My garden is most likely going to be filmed for Central Texas Gardener in June
of this year. I have to determine when I feel it's at peak. I was floored when
the offer was made. I'm so excited I can hardly believe it.

Cool! You'll enjoy Linda and her crew. She's a bit of an oddball, but she's
very sweet and easygoing.

Cheers.

--
Victor M. Martinez

http://www.che.utexas.edu/~martiv

On Fri, 7 Mar 2003 16:10:57 +0000 (UTC), (Victor
M. Martinez) wrote:

Yes, but it while it may be toxic levels, it is not toxically available unless
it is met with other elements.

It is not available, period!

Well, yes and no. :-) Phosphorus is in constant flux in soil (a
single atom of phosphorus could be available and unavailable to the
plant several times a day). Roots hairs exude acids that solubilize
nearby phosphates.

While there might be an excess of phosphorous,
that doesn't mean plants don't need bio-available phosphorous to thrive.
Our plants respond great to bone meal. I'm sure if we test our soil it would
be high in phosphorous.

I don't see where more P can ever be a solution to high P. At some
point the owner has to begin the process of removing more phosphorous
from the soil than is being applied, or suffer increasing problems
from P in the long run.

One interesting question (at least to me :-) is why is there so little
bioavailable phosphorous in the first place. My own conjecture is
that it may be due to the impact of our soil cultural practices on
root mycorrhizal fungi.

Almost all plants in nature maintain and have evolved to take
advantage of mycorrhizal associations (myccorhiza - symbiotic soil
fungi that provide water and minerals to the plant in exhange for
sugar and protein). A primary mineral made available by mycorrhizae
is phosphorous.

Conversely mycorrhizal colonization and growth are inhibited by even
high-moderate soil phosphorous (and a number of other nutrients and
lawn/garden chems). Applications of P can even kill plants with
established mycorrhizal relationships. So as we use more and more
exogenous P the soil flora continues to decline, and natural soil
cycling of P decreases. The plants become largely dependent on
frequent high doses of externally applied P. Fe and Z soon become
unavailable, so we supplement those too. On and on...

Perhaps an effective treatment for high P would involve removal of
grass clippings and leaves followed application of a low-P organic
fertilizer. Synthetic fertilizers and compost (which tends to be
poorly analyzed but in general relatively high in P) would be avoided.

On Fri, 07 Mar 2003 13:26:54 -0600, (Joe Doe)
wrote:

You are partially correct (& practically correct). Phosphorous is
generally found as a precipitate because it precipitates with Aluminium
and Iron at acidic pH ranges and with Calcium in Alkaline pH ranges. So
under many common soil conditions it will not be mobile or available.
Because our soils are so alkaline it is generally found as a calcium
precipitate. If you do suceed in moving the pH to neutrality with sulfur
more phosphate becomes available but it is unlikely to ever really
runoff.

Phosphorous is generally associated with surface runoff rather than
through percolation.

OTOH a relatively fast moving, dilute P solution formed during a storm
event over porous soil offers a higher likelihood of phosphorous
runoff than that posed by normal irrigation rates. Since phosphorous
is rate-limiting for O2-depleting algal blooms even a few percent
runoff is significant,

The fact that phosphate levels are of the scale is widespread: for
example in the book Gardening In the Humid South (written by two retired
Louisiana State Horticulture researchers one of whom has expertise in soil
science) they say this is also true for all measurements made in
Louisiana. They make the same point that you do: even though the
Phosphate is off the charts, that does not mean it is available. They
recommend side dressing. They approach this reluctantly because the
phosphate sources are not renewable yet do come down on the side of adding
some.

It strikes me as rather like maintaining an addiction that you know
one day you must kick or it will get you in the end.

Do they propose a turning point - some method by which the overuse of
phosphorous fertilizers will be reversed and soils restored?

On Fri, 07 Mar 2003 14:48:17 GMT, animaux
wrote:

Compost should not be used on soils where phosphorous levels are known
or suspected to be high.

Why?

Compost's chemistry is generally poorly quantified if at all, and its
phosphorous content can be quite high. This is standard Aggie soil
lab recommendation.

In article ,
(Terry Horton) wrote:



Phosphorous is generally associated with surface runoff rather than
through percolation.

That is true. But then it is also a problem of managing erosion/land
management.


The fact that phosphate levels are of the scale is widespread: for
example in the book Gardening In the Humid South (written by two retired
Louisiana State Horticulture researchers one of whom has expertise in soil
science) they say this is also true for all measurements made in
Louisiana. They make the same point that you do: even though the
Phosphate is off the charts, that does not mean it is available. They
recommend side dressing. They approach this reluctantly because the
phosphate sources are not renewable yet do come down on the side of adding
some.

It strikes me as rather like maintaining an addiction that you know
one day you must kick or it will get you in the end.

Do they propose a turning point - some method by which the overuse of
phosphorous fertilizers will be reversed and soils restored?

I actually think this "overuse" of phosphate fertilizers story is not the
only issue. It is also a land management issue to minimise surface
erosion. It appears that there is plenty of phosphorous already in many
soils (not applied).

For example, the extension at Nebrasca Lincoln says: "Nebraska soils are
generally well supplied with phosphorus. Total phosphorous content
average about 4700 pounds phosphorous pentoxide per acre for each foot of
soi. Assuming a root zone of six feet, most Nebraska soils contain about
28,000 lbs of total phosphorus as phosphorous pentoxide. If our crops
could use all of this phosphorus we would have a 500 year supply for
growing 150 bushels of corn per acre each year. Unfortunately, only a
very small amount of this total phosphorus supply is available each year
because it must undego weathering before it becomes available to plants.
Even with 28,000 lbs of total phosphorus present in the root zone,
phosphorus may be deficient for maximum crop yields." (found at
http://www.ianr.unl.edu/pubs/soil/g601.htm).

Incidentally this PDF (http://pubs.cas.psu.edu/FreePubs/pdfs/uc162.pdf)
has a nice picture of the distribution of areas in the country with high P
and addresses many issues of management.

What all this ignores is the practical problem of dosing a plant with
phosphorous (even in the presence of a lot of bound unavailable
phosphrous). This returns us to the book: What they actually recommend
doing is applying phosphate as a band. This is the most effective way of
using phosphate because you minimise the soil to phosphate interaction
area (it will only interact at the edges and a core area will not be in
contact with the soil. This ensures that only the material at the
boundaries becomes unavailable because of soil interactions while the rest
continues to be available. All that has to happen is a root has to find
the band and then it can mainline enough phosphorous for the whole plant.
This is similar to old garden advice of putting bone meal in a planting
hole -i.e. you put it where you want the root to find it. The opposite
way of applying phosphorus is broadcasting where in fact the soil to
phosphorus contact area is maximixed,

The book is written in a style where two old codgers are debating how to
do things: In general it is relatively superficial because it is wide
ranging. They are not overly dogmatic over too much: for example they
describe fertilization practices for a lawn and then say they themselves
do not do what they recommend - they say they fertilize every other year
or so because they do not particularly care about their lawns and do not
want to mow or water often and so limit fertilizer.

Despite the light treatment of many topics, they raise other interesting
points:

1) Predatory insects as a control mechanism cannot work too effectively,
because if the prey levels fall too much the predator will move to greener
pastures. They say fire ants are the champion predators (much better than
ladybugs etc.) and if you could find a way to live with them, you would
have a tick and flea free yard!!

2) Raise the possibility of mulches having allelopathic effects:
strawberries mulched with hay yield considrably less than those mulched
with a synthetic mulch. I have since done a search and confirmed
literature exists on allelopathic effects of various mulches. This shows
the world is more nuanced than the genrally held view that mulching only
does good.

Roland

On Sat, 8 Mar 2003 18:33:46 +0000 (UTC), (Victor M.
Martinez) wrote:


Cool! You'll enjoy Linda and her crew. She's a bit of an oddball, but she's
very sweet and easygoing.

Cheers.

Great! I stand there in the barren garden of winter and see every single thing
wrong, nothing right! I suppose I'm a typical gardener who is never content.
I've been pruning and pulling and xplanting and shaping and, well, you know the
work of early spring.

I did see bees and wasps and lacewings and the lizards are moving faster and the
pond is starting to green up with foliage, the echinacea is peeking up and life
is good.

Victoria

On Sat, 08 Mar 2003 23:52:50 GMT, (Terry Horton) wrote:

On Fri, 07 Mar 2003 14:48:17 GMT, animaux
wrote:

Compost should not be used on soils where phosphorous levels are known
or suspected to be high.

Why?

Compost's chemistry is generally poorly quantified if at all, and its
phosphorous content can be quite high. This is standard Aggie soil
lab recommendation.

I rarely follow aggie instructions, nor do I always trust their methods...being
a land grant University and all.

I've been a gardener all my life and nothing has ever been more viable to soil
structure and texture than compost. I'll stick with my own findings.

On the other hand, finally the aggies came to the conclusion all of us organic
gardeners have known for decades that, slow release organic fertilizer is
superior to any and all other forms of synthetic fertilizers. They don't force
feed and make turf dependant, but they add OM to the soil which feeds organisms
which make available elements which otherwise would be tied up in the soil.

Thank you FINALLY Texas A&M.

Terry Horton wrote:
Well, yes and no. :-) Phosphorus is in constant flux in soil (a
single atom of phosphorus could be available and unavailable to the
plant several times a day). Roots hairs exude acids that solubilize
nearby phosphates.

And the same acids are readily neutralized by the soil. I'd agree there is
a state of flux, but I'm guessing the overall balance remains neutral.

point the owner has to begin the process of removing more phosphorous

If the P available is not bio-available, then the plants will suffer from
lack of P. But you know this.

from the soil than is being applied, or suffer increasing problems
from P in the long run.

So how do you propose dealing with the fact that the P in the soil is not
available for plants to use? Acidify the soil? That ain't gonna work.

Perhaps an effective treatment for high P would involve removal of
grass clippings and leaves followed application of a low-P organic
fertilizer. Synthetic fertilizers and compost (which tends to be
poorly analyzed but in general relatively high in P) would be avoided.

I fail to see how that would make existing P available for the plants. Am
I missing something?

--
Victor M. Martinez

http://www.che.utexas.edu/~martiv

On Sat, 08 Mar 2003 19:38:11 -0600, (Joe Doe)
wrote:

In article ,
(Terry Horton) wrote:



Phosphorous is generally associated with surface runoff rather than
through percolation.

That is true. But then it is also a problem of managing erosion/land
management.

Hopefully not a big issue for most home gardeners. :-)

Incidentally this PDF (http://pubs.cas.psu.edu/FreePubs/pdfs/uc162.pdf)
has a nice picture of the distribution of areas in the country with high P
and addresses many issues of management.

An impressive little publication. I've saved it to my HD. Thanks.

The book is written in a style where two old codgers are debating how to
do things: In general it is relatively superficial because it is wide
ranging. They are not overly dogmatic over too much: for example they
describe fertilization practices for a lawn and then say they themselves
do not do what they recommend - they say they fertilize every other year
or so because they do not particularly care about their lawns and do not
want to mow or water often and so limit fertilizer.

Despite the light treatment of many topics, they raise other interesting
points:

1) Predatory insects as a control mechanism cannot work too effectively,
because if the prey levels fall too much the predator will move to greener
pastures. They say fire ants are the champion predators (much better than
ladybugs etc.) and if you could find a way to live with them, you would
have a tick and flea free yard!!

Green lacewing adults feed on nectar and pollen. Providing food
sources during the adult stage encourages them to stay put. And you
can always re-apply. ;-)

Fire ants? Ever see the movie "The Naked Jungle"? A cure worse than
any disease.

2) Raise the possibility of mulches having allelopathic effects:
strawberries mulched with hay yield considrably less than those mulched
with a synthetic mulch. I have since done a search and confirmed
literature exists on allelopathic effects of various mulches. This shows
the world is more nuanced than the genrally held view that mulching only
does good.

This has been understood for many years. Don't most mulches lose their
allelopathic effects with age?

On Sun, 09 Mar 2003 20:07:25 GMT, animaux
wrote:

On Sun, 09 Mar 2003 20:07:25 GMT, in austin.gardening you wrote:

On Sat, 08 Mar 2003 23:52:50 GMT, (Terry Horton) wrote:

On Fri, 07 Mar 2003 14:48:17 GMT, animaux
wrote:

Compost should not be used on soils where phosphorous levels are known
or suspected to be high.

Why?

Compost's chemistry is generally poorly quantified if at all, and its
phosphorous content can be quite high. This is standard Aggie soil
lab recommendation.

I rarely follow aggie instructions, nor do I always trust their methods...being
a land grant University and all.

One aggie pest control seminar I attended should've been titled "How
to Become a Superfund Site". :-) I left with an arm-length list of
chemical pesticides, with hardly a mention of an alternatives.

But there's a sustainable gardening wing at aggieland universities
too. Remember that our Texas Master Gardener and Texas Master
Naturalist programs are out of TAMU. Benny Simpson, Skip Richter,
Jill Nokes to name a few... all Aggies products. The fellow that held
the lecture on high P soils was recommending Sustane (this was
pre-Ladybug :-).

I've been a gardener all my life and nothing has ever been more viable to soil
structure and texture than compost. I'll stick with my own findings.

Whatever works for you.

On the other hand, finally the aggies came to the conclusion all of us organic
gardeners have known for decades that, slow release organic fertilizer is
superior to any and all other forms of synthetic fertilizers. The y don't force
feed and make turf dependant, but they add OM to the soil which feeds organisms
which make available elements which otherwise would be tied up in the soil.

Whether or not this applies to you in Round Rock you'll have to
determine. Organic gardeners (like me) who live on high-moderate P
soils (100ppm or so) can not turn away from the devastating effect on
soil mycorrhizae referred to earlier. Mycorrhizal association is an
_integral part_ of the physiology of most of the plants we grow.

Reducing nutrient input to help grow soil organisms that will extract
those nutrients for you.... organic gardening doesn't get any more
cool than that.

On Mon, 10 Mar 2003 15:20:52 +0000 (UTC),
(Victor M. Martinez) wrote:

Terry Horton wrote:
Well, yes and no. :-) Phosphorus is in constant flux in soil (a
single atom of phosphorus could be available and unavailable to the
plant several times a day). Roots hairs exude acids that solubilize
nearby phosphates.

And the same acids are readily neutralized by the soil.

And more is exuded. Plant roots actively maintain a lower pH
microclimate in the rhizosphere. In fact the zone immediately around
the roots is quite different from the surrounding soil. Sugars,
enzymes, amino acids, lipids, all manner of compounds are "oozed" into
the adjacent soil.

Plants are not just passive recipients of whatever is in solution
around them. They in effect chemically "mine" surrounding minerals,
and feed other organisms in return for a supply of water and minerals

I'd agree there is
a state of flux, but I'm guessing the overall balance remains neutral.

Depending on where it and how it was measured... an plug of our soil
would show a pH of 8-9. A few microliters next to the root tip might
be 1.5-2 points lower.

point the owner has to begin the process of removing more phosphorous

If the P available is not bio-available, then the plants will suffer from
lack of P. But you know this.

Are you seeing evidence of P deficiency?

from the soil than is being applied, or suffer increasing problems
from P in the long run.

So how do you propose dealing with the fact that the P in the soil is not
available for plants to use? Acidify the soil? That ain't gonna work.

Anything that produces hydrogen will temporarily acidify the
*immediate* soil microclimate. But sulfur, etc. aren't the answer
imho.

It's a tough deal for west Austin. We all wish there were win-win
answers, but there aren't. At this point the best recommendation is
to use low P, slow release organic fertilizers like those already
mentioned in this thread.

Perhaps an effective treatment for high P would involve removal of
grass clippings and leaves followed application of a low-P organic
fertilizer. Synthetic fertilizers and compost (which tends to be
poorly analyzed but in general relatively high in P) would be avoided.

I fail to see how that would make existing P available for the plants. Am
I missing something?

It's well established that even low level of P fertilizer reduce or
eliminate mycorrhizal activity. One of the most dramatic effects of
mycorrhizal colonization is increased P uptake, which they take from
the large pool of "unavailable" P.

On Mon, 10 Mar 2003 18:00:26 GMT, (Terry Horton) wrote:

But there's a sustainable gardening wing at aggieland universities
too. Remember that our Texas Master Gardener and Texas Master
Naturalist programs are out of TAMU. Benny Simpson, Skip Richter,
Jill Nokes to name a few... all Aggies products. The fellow that held
the lecture on high P soils was recommending Sustane (this was
pre-Ladybug :-).

I didn't know that about Jill Nokes. I do know the Grow Green program and it is
getting there, slowly.


Whether or not this applies to you in Round Rock you'll have to
determine. Organic gardeners (like me) who live on high-moderate P
soils (100ppm or so) can not turn away from the devastating effect on
soil mycorrhizae referred to earlier. Mycorrhizal association is an
_integral part_ of the physiology of most of the plants we grow.

I have a mixture on our land. Some is very calciferous and caliche, some is
black, but friable, then there's what I call "the goo!" I garden accordingly.
We are on the same page regarding mycorrhiza. I've been using it for several
years now. On plants which benefit, I use some on the roots at planting time.
I mixed the soil once, when we first bought the house. I'm very gentle on it
now so I don't disturb the fungal mat I've created. Have you ever watched the
series with David Attenborough "Private life of Plants?" I bought the
collection on VHS some years ago. I've yet to see anything remotely close to
showing the world how plants work and how phenology represents when.


Reducing nutrient input to help grow soil organisms that will extract
those nutrients for you.... organic gardening doesn't get any more
cool than that.

Agreed.