AM Fungi and Phosphorus

rrog · Jan 24, 2010

I was reading with interest an older thread about this topic, but apparently everyone didn't play well in the sandbox, and so much of the original conversation was deleted. A shame. I am absolutely not looking to neither start nor resurrect a war, but would be interested in any links to hard data or experienced anecdotal analysis of data regarding the topic. Not looking for urban legends. So please, if there are studies and data, I'm interested. There's just no reason this can't be discussed in a civil manner.

Specifically, I'm wondering if adding high levels of P during flower is a waste and potentially counterproductive. I've read a few times where some say that AM Fungus is unnecessary, since the required P load during flower will kill them anyway. I wonder if that's not the backward way to look at the scenario.

Some basic tenets:

- We know that P is critical for flower (and root) development.

- We know that AM Fungus will provide P to plant roots, breaking down the P stored in raw organic forms such as bone meal.

- We know that very high levels of especially inorganic (nute) sources of P can inhibit the function of AM.

What I've read a bit about is that if the AM fungi are in place, they very much regulate the P availability to the roots. Microbeman states that once growing with natural techniques, the addition of P to the medium did not change the flower growth. That would seem to point to the fact that either:

1) The plant was getting all the P it could use without the addition of inorganic supplementation because of the actions of the AM Fungus.

OR

2) The AM Fungus was inhibiting the ability of the roots to have access to the added P.

#1 seems more plausible to me.

If this is the case, and the AM is mining all the P the plant can stand, then we should be leaving well enough alone and not seek to add loads of inorganic P during flower. To do so would only be a waste and risk interrupting the actions of the AM Fungus.

Is this the case?

Thanks for staying civil.

big ballin 88 · Jan 24, 2010

i think if you've been around the forum long enough you've heard how to much P can kill the microherds. From reasearch i had done after reading that topic too much P can be deadly. I think if your doing organics correctly already the plants should be bringing in all the P they can anyways and adding so much extra P wouldn't benefit anything.

However, I would like to know what would happen if someone would try to foliar feed to bypass the micro's.

Lets see where this one goes good luck.

rrog · Jan 24, 2010

big ballin 88 said:
i think if you've been around the forum long enough you've heard how to much P can kill the microherds.

I've also heard that at least some AM won't die at higher P and that some will continue to perform at quite high P levels. But for the sake of this thread, I have assumed the AM is out of the picture if P is too high.

I think if your doing organics correctly already the plants should be bringing in all the P they can anyways and adding so much extra P wouldn't benefit anything.

However, I would like to know what would happen if someone would try to foliar feed to bypass the micro's.

I think some might say that the plant may be getting all the P it needs from the herd and even foliar wouldn't improve. Some might say that. I have no idea.

Lets see where this one goes good luck.

Thanks for stopping in.

Dignan · Jan 25, 2010

I want to see MM in this thread. :whistling:

rrog · Jan 25, 2010

Me too...

Microbeman · Jan 25, 2010

I believe the old thread you were speaking of involved Mr. Ganja Din and he may have posted links to literature(?). My take in general off the top of my head is that high levels of P (especially soluble or readily soluble) do inhibit AM activity. If there is AM infection of the roots then low levels of sequestered P like in rock phosphate, compost, etc. is likely adequate. However Mr. Din also raised the question of whether there is sufficient time in the short life cycle of most indoor cannabis to become infected with AM. This is based on the observation that in most published experiments it seems to take 4 to 6 weeks for infection to take. I believe there is better chance of infection in two scenarios if applying endomycorrhizal spores;
1/ use spores applied to your cuttings when prepping for rooting or when planting seeds
2/ in the case of using a living soil system where the plant is cut down at harvest but the roots are left in the soil; if those roots were infected by AM, the act of killing the plant triggers the fungi to sporulate, leaving spores in the soil which are more likely to sprout when they come in contact with new roots; also this fungi will become 'acclimatized' to your system over several seasons.

AND
If this is indeed how long it takes for AM infection, then a 4 to 6 week vegetative period should provide a good time frame. I have seen white fungi growing out from rooted cuttings but did not confirm they were AM. This infection took place in around 12 days. Bear in mind too that these experiments are in the lab and I have not read them all to ascertain if any were strictly soil based. What happens in the soil, often cannot be replicated in the lab. Yet one more thing to investigate.

Microbeman · Jan 25, 2010

Grow your own mycorrhizae

http://newfarm.rodaleinstitute.org/depts/NFfield_trials/0903/daviddouds.shtml

rrog · Jan 25, 2010

Thanks for stopping by, MM. I didn't even have time to shine the big MM light in the sky to call for your assistance...

That was the thread I was referring to.

So your initial feeling is that well-established AM would likely feed the plant all the P it needs. Makes sense as a very interesting article I read described how the fungus will pull P from quite a distance away and transport this to the roots.

A personal anecdote about fungus. I used Myco Madness to start my medium brewing. The medium is very fluffy and I have two large airstones in the bottom of the pail in a water layer. Huge humid air movement comes up. Within a week there were very visible fungal colonies on the top of the medium. I was told to expect this, as the AM is very receptive to the warm, moist air availability.

Microbeman · Jan 25, 2010

rrog said:
Thanks for stopping by, MM. I didn't even have time to shine the big MM light in the sky to call for your assistance...

That was the thread I was referring to.

So your initial feeling is that well-established AM would likely feed the plant all the P it needs. Makes sense as a very interesting article I read described how the fungus will pull P from quite a distance away and transport this to the roots.

A personal anecdote about fungus. I used Myco Madness to start my medium brewing. The medium is very fluffy and I have two large airstones in the bottom of the pail in a water layer. Huge humid air movement comes up. Within a week there were very visible fungal colonies on the top of the medium. I was told to expect this, as the AM is very receptive to the warm, moist air availability.

What do you mean by 'medium brewing'? Do you mean a liquid like tea or your planting medium? It is very unlikely that what you are seeing is AM fungi, as to the best of my knowledge (outside of one lab report I heard of from Mr. Din) AM spores only sprout in contact with the root host. If you were told to expect this then someone perhaps is ill informed. There is a greater likelihood that you are seeing Thrichoderma fungi which is often included in these commercial mixes. [There is discussion and research occuring in the scientific community concerning the antagonistic or inhibitory effects of Trichoderma on AM. There is evidence that Trichoderma can prevent AM infection of roots but there are arguments to the contrary. I'm hoping to post my conclusions/opinion within a month.] Alternatively you are growing some ectomycorrhizal fungi which is in the mix or some local fungi/mold.

I don't recall stating this;

Microbeman states that once growing with natural techniques, the addition of P to the medium did not change the flower growth.

If I did say something like this, what I intended was that we noticed no appreciable difference in flower size once we were growing 'naturally' and no longer using high amounts of P.

rrog · Jan 25, 2010

Thank you for asking for clarification.

I'm using a system that has a lava rock filled lower 1/3 layer in a 5 gallon pail. Air hoses and bubblers are in this layer.

The top 2/3 layer is a very open, airy mix of large media such as coco chunks, coarse vermiculite and coarse perlite. This allows the humid air to bubble up freely.

The "Medium Brewing" in my vernacular means the medium, Myco and amendments were initially mixed, watered, and let bubble in the 5 gallon pail for 2-3 weeks before a plant is introduced.

The fungus I saw and photographed were probably Thrichoderma as you said. However between the 3 weeks of bubbling + 4 week veg period, I'm definitely in the timetable to have active AM Fungus by the time the plants get very large or flowering.

Your quote was from that ill-fated thread. So you were referring to an informal side by side observation of chem fertilized plant vs. an organic micro-herd grow. Assuming your group would have increased the P to max levels in the chem fert "trial" , this bodes well for my speculation that we just don't need to add much inorganic sources of P during a (organic grown)flower period. That's my main query.

Thank you for your insights MM. I know you're very busy.

ganja din · Jan 25, 2010

I tend to agree with MM

I tend to agree with MM

Hey all,

I know I haven't posted in a while, and I am not really sure why I am right now, besides that this question of AM fungi *needs* to be vetted once and for all. (please don't assume this means I am returning to this site, I am not, I did however what to assist Tim in his endeavors)

Please see this paper:

"The Soil is Alive!"
Jodi DeJong-Hughes, University of Minnesota Extension; 2009
http://www.extension.umn.edu/distribution/cropsystems/M1272.html#7

In the following screenshot you will see that plants get a good amount of P from other soil foodweb organisms and the nutrient cycle. Even tho P from AM fungi infected plants is about twice that from non-infected plants...however, note that *no* extra P (Ie. guanos, etc) were added to the soil for the following data:

big ballin 88 · Jan 25, 2010

Microbeman said:
What do you mean by 'medium brewing'? Do you mean a liquid like tea or your planting medium? It is very unlikely that what you are seeing is AM fungi, as to the best of my knowledge (outside of one lab report I heard of from Mr. Din) AM spores only sprout in contact with the root host. If you were told to expect this then someone perhaps is ill informed. There is a greater likelihood that you are seeing Thrichoderma fungi which is often included in these commercial mixes. [There is discussion and research occuring in the scientific community concerning the antagonistic or inhibitory effects of Trichoderma on AM. There is evidence that Trichoderma can prevent AM infection of roots but there are arguments to the contrary. I'm hoping to post my conclusions/opinion within a month.] Alternatively you are growing some ectomycorrhizal fungi which is in the mix or some local fungi/mold.

I don't recall stating this;

If I did say something like this, what I intended was that we noticed no appreciable difference in flower size once we were growing 'naturally' and no longer using high amounts of P.

Hey MM,

I know what you mean about the seeing trich in the soil vs. AM. One way you can tell if its trich is to rub it with some H202 and see if its bubbles away and change color.

I THINK, one way you can tell if your colonized with AM is the way the soil holds together. I've had plants that weren't even close to rootbound, that was able to hold the soil so tightly together it pulled away from the edges, much like my mushrooms cakes would do. I haven't seen or heard trich holding the soil like that, but have heard that AM will link hyphae to increase surface area and in turn can do this and see the some of the hyphae on top of the soil.

Also trich is very good at taking over other fungi's food sources, so it would make sense that if it has a foothold is goona hold it over AM. This is typical for fungi, if one has the foothold first than its gonna stand a greater chance. What if i pasteurized the soil and than added AM after? Would i have to grow a certain plant and try and culture it from their roots specfically or could i try to culture some onto agar using a start of spores? That will be hell of a job but it can be done, time to fire up the flowhood!! :hide:

rrog · Jan 25, 2010

man that's interesting BB88. Thanks a lot for adding this to the thread.

Does anyone think it's possible that the AM could grow faster in the higher airflow medium I'm using? That's part of the rationale for the system. Increased airflow for the micro-life.

ganja din · Jan 25, 2010

rrog said:
Your quote was from that ill-fated thread. So you were referring to an informal side by side observation of chem fertilized plant vs. an organic micro-herd grow. Assuming your group would have increased the P to max levels in the chem fert "trial" , this bodes well for my speculation that we just don't need to add much inorganic sources of P during a (organic grown)flower period. That's my main query.

Thank you for your insights MM. I know you're very busy.

Hey rrog,

There is nothing 'informal' about the ppm levels I cited, and there was no side by side for chem feed vs. bio-chem feed. The 'chems', ie, ions are the same in both situations. What do you consider "inorganic"? Why would anyone add chems to organic grow? Don't use AM fungi and apply P amendments like colloidal phosphate, light amounts of guanos, etc.

HTH

ganja din · Jan 25, 2010

big ballin 88 said:
Hey MM,

I know what you mean about the seeing trich in the soil vs. AM. One way you can tell if its trich is to rub it with some H202 and see if its bubbles away and change color.

Trich is green without any H202, it is only white when it's young. And I think your referring to "cobweb" mould as to "bubbling", that is why H202 is used in mycology for cobweb.

I THINK, one way you can tell if your colonized with AM is the way the soil holds together. I've had plants that weren't even close to rootbound, that was able to hold the soil so tightly together it pulled away from the edges, much like my mushrooms cakes would do. I haven't seen or heard trich holding the soil like that, but have heard that AM will link hyphae to increase surface area and in turn can do this and see the some of the hyphae on top of the soil.

Many things will "glue" media particles together, mycosphers from non-AM fungi, bacterial bio-film and even plant exudates.

Also trich is very good at taking over other fungi's food sources, so it would make sense that if it has a foothold is goona hold it over AM. This is typical for fungi, if one has the foothold first than its gonna stand a greater chance. What if i pasteurized the soil and than added AM after?

Trich *eats* AM fungi, not the AM fungi's foodsource.

ganja din · Jan 25, 2010

rrog said:
man that's interesting BB88. Thanks a lot for adding this to the thread.

Does anyone think it's possible that the AM could grow faster in the higher airflow medium I'm using? That's part of the rationale for the system. Increased airflow for the micro-life.

No I don't think so. AM fungi prefer media with higher Co2 levels.

ganja din · Jan 25, 2010

rrog said:
I was reading with interest an older thread about this topic, but apparently everyone didn't play well in the sandbox, and so much of the original conversation was deleted. A shame. I am absolutely not looking to neither start nor resurrect a war, but would be interested in any links to hard data or experienced anecdotal analysis of data regarding the topic. Not looking for urban legends. So please, if there are studies and data, I'm interested. There's just no reason this can't be discussed in a civil manner.

Specifically, I'm wondering if adding high levels of P during flower is a waste and potentially counterproductive. I've read a few times where some say that AM Fungus is unnecessary, since the required P load during flower will kill them anyway. I wonder if that's not the backward way to look at the scenario.

Some basic tenets:

- We know that P is critical for flower (and root) development.

- We know that AM Fungus will provide P to plant roots, breaking down the P stored in raw organic forms such as bone meal.

- We know that very high levels of especially inorganic (nute) sources of P can inhibit the function of AM.

What I've read a bit about is that if the AM fungi are in place, they very much regulate the P availability to the roots. Microbeman states that once growing with natural techniques, the addition of P to the medium did not change the flower growth. That would seem to point to the fact that either:

1) The plant was getting all the P it could use without the addition of inorganic supplementation because of the actions of the AM Fungus.

OR

2) The AM Fungus was inhibiting the ability of the roots to have access to the added P.

#1 seems more plausible to me.

If this is the case, and the AM is mining all the P the plant can stand, then we should be leaving well enough alone and not seek to add loads of inorganic P during flower. To do so would only be a waste and risk interrupting the actions of the AM Fungus.

Is this the case?

Thanks for staying civil.

P.S.

Fungus = singular

Fungi = plural

ganja din · Jan 25, 2010

rrog said:
We know that very high levels of especially inorganic (nute) sources of P can inhibit the function of AM

Hey,

No I wouldn't say that is accurate, the question is, what is "high"? In general high levels are not needed, at 32 ppm of P (that's from organic or inorganic sources, ions are ions) AM fungi will not sporulate and infections is greatly reduced. Past 20 ppm of P and AM fungi are greatly inhibited. So you see, that is why in the graph I uploaded AM fungi offer more P, because *NO* P was added to media. If P was added (ie. as gunao or colloidal phosphate) the P absorbed from non-infected plants would be higher.

No added P = use AM fungi

Added P = don't need to use AM fungi and probably a waste
(unless as MM noted, it's all sequestered P as in colloidal phosphate and only a little is added)

Microbeman · Jan 25, 2010

Would i have to grow a certain plant and try and culture it from their roots specfically or could i try to culture some onto agar using a start of spores?

Every lab method I've seen involves culturing from the root system.

I just breezed through the old thread and all Ganja Din's posts are gone....perhaps self-inficted; too bad the citations are gone.

rrog · Jan 25, 2010

Microbeman said:
Every lab method I've seen involves culturing from the root system.

I just breezed through the old thread and all Ganja Din's posts are gone....perhaps self-inflicted; too bad the citations are gone.

That is a sad thing about that thread. I would have liked to have seen the whole thing.

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