Research from the summer of 2008 revealed yet again the many benefits of using mycorrhizal fungi when planting. This particular study provided some interesting insights. One group of plants (of various species) was fertilized with traditional chemical fertigation and the other group was fertilized with a mix of slow-release chemical fertilizer and rock phosphate. Both sets of plants were also inoculated with mycorrhizal fungi.
The plants that received chemicals did not do very well at forming mycorrhizal relationships with the fungi. This could partially be due to the toxicity of the chemical fertilizer, but in the study, it was attributed to the fact that the plants did not need to form the relationship because they were being spoon-fed nutrients. The plants that received the slow-release fertilizer and rock phosphate did much better at forming mycorrhizal relationships. This slow-release fertilization strategy was meant to mimic the way that phosphorus is generally found in the soil, in random concentrated pockets and in insoluble form.
Not only did the latter group of plants have better colonization, they had improved efficiency of nitrogen use and a substantially higher survival rate. More and more studies are correlating mycorrhizal fungi with improved nitrogen use, and we have known for a long time that survival rates are higher when mycorrhizal fungi are present.
This study reiterated many of the common previous successes with mycorrhizal fungi, but to me, a new implication of this is that while fertilizing with chemicals is counter-productive, adding a very small amount of rock phosphate in with your mycorrhizal fungi when planting might be a good idea to help improve colonization of plant roots. I am particularly excited at the prospect of getting soft rock phosphate in later this spring, which is currently impossible to find in BC (more on that soon). I will definitely look more into this.
In the meantime, it still stands that mycorrhizal fungi should be used every time anything is planted or seeded. Leave the bone meal behind (potential spreading of mad cow disease prions) and bring a bag of fungi instead. Survival rates will go up and plant health will be greatly improved. Better water uptake, phosphorus, many other nutrients, protection from pests – the list goes on. In fact, trees are thought to have evolved because of the existence of this fascinating relationship.
I have attached the above study to this newsletter. I have also included links to two very short (2 minute) videos on mycorrhizal fungi below.