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Old 07-05-2013, 07:02 AM
Smallaxe Smallaxe is offline
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Location: Central Wisconsin
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Quote:
Originally Posted by Skipster View Post
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.

Research has found that most crops for this association on their own within hours after germination. ...
http://www.plantphysiol.org/content/156/3/1050.full#F1
"... The influence of different forms of P present in soils on the availability and uptake of P from natural and fertilizer sources remains the subject of active research (Bünemann et al., 2011). It is generally accepted that AM and NM plants access the same forms of inorganic soil P, including P that is reversibly adsorbed to various soil minerals and exchanges with the soil solution (Marschner, 1995; Frossard et al., 2011). Many AM plants can acquire more total P than NM plants from the same soil, which is thought to involve increased spatial exploitation by hyphae in soil (Marschner, 1995). The competition for P in soil between AM fungal hyphae and roots has already been raised as a possible explanation for reduced uptake via the direct pathway, but it is hard to accept in situations where plants are poorly colonized and root and hyphal length densities are low."

That paragraph agrees with your point, but notice from the following,,, it does not stop there... So let me rephrase the question about soil tests... Does the test report "poorly available P" or "organic P", as is refernced in the following statements???
If all bases are covered and the test is for turf,,, with an understanding that it is likely AM innoculated(naturally) then perhaps there are P deficient soils,,, especially,,, on lawns that bag...


"... Positive mycorrhizal growth responses can increase if poorly available P is applied to soil, even for plants that show little or no positive response at low P. This finding shows that AM plants can access poorly available P more effectively than NM plants, but the mechanisms by which they do so are not well understood (Bolan, 1991). There is some evidence that AM fungi can exploit sources of organic P in soils, but the quantitative contribution of this process to the supply of P to plants is probably small (Joner et al., 2000). Higher exploitation of poorly available soil P by AM plants is increasingly important in the contexts of understanding AM responsiveness and the utilization of poor-quality fertilizer sources. All these uncertainties require investigation if we are to understand the soil-AM plant continuum relating to P uptake. "
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Now that I know that clay's texture(platelets) has nothing to do with water infiltration, percolation, or drainage
,,, I wonder what does...
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