Composted organic matter is placed over the soil and then stirred into the top 4 to 6 inches of soil with an Air Spade or Air Knife to help promote new root growth.
Compost and Soil Stirring Another method that we use to improve soil conditions around an established tree is to spread compost or other substrate medium high in soluble organic carbon over the soil surface beneath the dripline of the tree. Then with the Air Spade or Air Knife we stir the soil mixing in the compost down to a depth of 4 to 6 inches as in the photo (right). Then following the compost stirring and mixing, 2 to 3 inches organic mulch is spread over the soil. The organic mulch applied in the final stage of the work is not shown is this image.
Mycorrhizal inoculations are often touted as beneficial but research has not shown them to be effective as a viable soil treatment. Part of the reason for this is that mycorrhizae are species specific. This means that applying generic spore “blends” will almost certainly not interact with your tree.