McCord Forest Services Ltd    -    027 333 7933   -    joanna@mccord.co.nz   -  03 313 4953   -

 

                         30 Pentecost road Rangiora 7400 North Canterbury New Zealand 

Boron and Fungal Growth - Mycorrhizal

I have always been intrigued why anyone would spend 2000 dollars for a kilo of truffles. Lets face it they are only mushrooms (Puffballs), and I have always been used to gathering them out in the field free of charge. I have recently been informed by a reliable source that trial work here in NZ to try and duplicate truffle production which they can obtain from Europe, has been a bit of a failure, and I wonder if boron could be the answer.

The reason I suggest this is because of our increase in mycorrhizal in our P Radiata stands after they have been treated with boron. Mycorrhizal is a symbiotic fungus which lives on the roots of P Radiata and it enables the tree to utilize nutrients in the soil.

I am convinced the importance of mycorrhizal is not fully understood and if it was I am sure our tree production could be drastically improved. Take for example a new tree nursery that has not been inoculated with mycorrhizal spores. The radiata seedlings germinate, and start growing very nicely but they never get anymore than an inch or to above the ground then they turn yellow. They are just starving to death. The reason is their root systems cannot access the available nutrients in the soil with out the help of mycorrhizal. Therefore before any new nursery is set up the nurserymen go mushroom collecting . These mushrooms are found around the root systems of radiata . They grow well when ground temperatures and adequate moisture is in abundance. These mushrooms are very similar to puff balls which grow underneath the duff layer, and are exposed for a short period of time before they burst. Normally it is extremely difficult to get enough of these puff balls to inoculate the entire nursery. Usually they are few and far between however you only need about 100 gms of dried puff ball spores to inoculate 1 Ha of nursery bed.

These puff balls were only available to be collected from our foothills forestry. They had never been evident on the plains before, so you can imagine my surprise when one of our Forest Rangers came in with a super market bag full of these mushrooms. When asked where he had got them from he told me Eyrewell forest . I was completely bewildered because up until then I had never seen one puff ball growing in any of the plains forests .

The reason why there was an abundant of these puff balls did not become clear until we visited the, "production site".

Boron application of this forest ceased after 1976 because of the deaths caused by uneven application of a Sodium Borate product. It wasn't until 1990 that boron was again applied to this forest as a boron chip from a spinner bucket slung underneath a helicopter using a guidance system.

These puff balls were growing quite prolific in areas that had been treated with boron three years previously. These areas had also been strip sprayed creating a moist bare earth environment ideally suited to fungus growth.

It was obviously the addition of boron that produced this bonanza of puff balls simply because where boron had not been applied no puff balls were present.

It was this basic observation that helped to explain to me why nutrient levels in our radiata became in balance after being treated with boron. The mycorrhizal had simply enabled the tree to take up the nutrients it needed and therefore was able to keep the nutrients in balance even from a quite deficient site.

I am not sure why mycorrhizal dramatically increases after a boron application. It may be because of the increase in root biomass we know that we achieve this after a boron application or it may be something to do with the change in soil conditions after the boron is applied. One thing I do know is this beneficial fungus dramatically increases in biomass after boron is applied therefore I suggest to all you truffle growers out there to give this boron theory a try and see if your truffle production increases. 
Are the fruiting bodies of the mycorrhizal fungus so different from the fruiting bodies of the truffle?