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Old 07-03-2013, 11:48 AM
Skipster Skipster is offline
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Join Date: Dec 2010
Location: Billings, MT
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Originally Posted by Smallaxe View Post

I appreciate that people believe that plant available P in their soil test reports is the only important numbers that matter,, but my point is that turf has the ability to utilize P beyond the "available P"...

The research does not support your opinion here. Several papers published in the journal Plant Physiology report that AMF does not increase the amount of P taken up beyond "available P", but instead expands the surface area from which "available P" can be extracted. AMF don't "mine" more P than roots do -- they just increase the area from which P can be found. They also report that AMF are ubiquitous in the soil and naturally form associations with more than 80% of all plants, Poaceae included.

Originally Posted by Smallaxe View Post
Whereas uninnoculated annual crops are not likely to have time to build the symbiosis with AMF and 'mine' the unavailable P
Research has found that most crops for this association on their own within hours after germination

Originally Posted by Smallaxe View Post
the reason I was curious about whether soil test would address ALL phos. in the soil is becuz turf grass potentially accesses ALL phos. in the soil...
Nothing can access ALL P in the soil. Remember, the soil test in only an index value. It's not a concrete number.

Originally Posted by Smallaxe View Post
This moves into new territory regarding the usefullness of ag. based soil test, so plz don't re-explain the current usage of soil test numbers... I'm challenging the concept of P being low for turfgrass just becuz the available P doesn't seem to be high enough for the lab technician running the test...
If I am missing something then perhaps I could be informed as to what EXACTLY I am missing,,, and perhaps it could be done in a manner of intelligent discourse ...
EXACTLY what you're missing is the very meaning of a soil test. It's not a concrete number and it has nothing to do with what a lab technician thinks. The test values and recommendations are backed up with decades of field research -- stuff that was actually done on lawns and research plots.

All the soil test does is find a way to assign a measurable value to a soil sample, correlate that value to plant activity, then calibrate fertilizer applications to the soil test value and to plant activity.

The absolute value of any soil nutrient is unneeded.
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