Originally Posted by Smallaxe
So what are you saying? Plants are better off without the Mycorrhizae?
What do these 2 paragraphs, from your link, mean?
I think it means exactly what it says. If there is enough phosphorus in the soil, the plant will grow deep roots to get it. If there isn't enough it will attract mycorrhizae to help it get what phosphorus is there.
I don't think she says that the plants are better off without mycorrhizae but it doesn't need them depending on the level of P. If you have plenty of P in the soil then the plants don't excrete the acid that attracts mycorrhizae so buying mycorrhizae to innoculate the soil would be a waste of money.
What seems like it might be interesting is if you start off providing enough phosphorus. This will cause the grass to work on bigger/deeper roots. This will help keep it looking better in the summer heat. Then let the phosphorus drop so mycorrhizae can colonize the roots. Now you have the previous root growth and mycorrihizae working together.
That's just speculation based on what she said. I haven't looked into it yet. It would depend on if the roots will shrink once P drops and if so how fast do they shrink. Maybe you need to do something like one year with P, 2 years without P or something like that. Would be an interesting experiment.