The topic of this newsletter was prompted by a note I recently received from a customer, who stated: "Three years ago I planted a small orchard of cherries using your product on all but one row -- I wanted to see if this stuff really worked. It did. The results were startling from the onset. However, I now need to get these trees up to their brothers rate of growth!!! How do I apply the product and at what rate?"
He has decided to try probing inoculant down to the root zones of the "Without" trees, and I hope the fungi will colonize them. However, as I told him, I have to wonder if it will be as effective at this later date as it was for his new transplants.
Nature does not leave things vacant for long, whether it be topsoil or the mycorrhizophere below ground. After a period of time, the root zones of all existing trees are occupied by native fungi and various other bioorganisms. I think it then becomes difficult or impossible to successfully introduce new players.
Note that this is speculation on my part, as I am not aware of any good research that has been done on this specific subject. I am aware that there are bio-supply companies that actively promote the application of expensive mycorrhizal inoculants to existing trees and claim that such applications produce wonderful results, but my sceptical side can't help feeling that the fertilizers and biostimulants that are injected at the same time might be entirely responsible for any positive responses.
If my logic is correct, then the opportunity to establish the most effective symbiotic match between a tree and the best type of fungi for that tree may be lost if other less-beneficial fungi are allowed to become dominant in the ecosystem around the roots. (I think that native fungi and native plants are almost certainly the best and most obvious match for each other, but introduced plant types often seem to respond better to introduced fungi.)
In other words, when setting out new trees or shrubs, I think an inexpensive dusting of multi-specie fungi spores on the roots - either Endo or Ecto types, depending on the tree type - makes good economic sense. Comparison tests such as done by the grower quoted above attest to the value of such planting-time inoculations.
However, for established trees, I doubt that simply putting new mycorrhizal fungi spores in the root zone will do any good. It is difficult to see how later entries can succeed in the competition for root exudates. (But, I freely admit that I could be wrong about this).
I personally think the best possibility for helping problem orchards or vineyards is to dust new spores on cover crop seeds. Then, as the legumes, grasses, or wildflowers activate and host the new fungi, the cover crop roots may transport those better fungi species down to the roots of the target trees or vines where they may co-colonize.
Trees are certainly capable of hosting multiple species of mycorrhizal fungi at the same time, and research has even shown that, for unknown reasons, the types of fungi found on a root system change as trees mature.
Still much to be learned. In the meantime, I just hope that row of cherry trees catches up!
Cheers, my friends,
Don Chapman
President, BioOrganics, Inc.