Soil ameliorates added to backfill in tree pits

[Thesnarlingbadger]

Hi people,

 

 Just looking for a bit of advice.

 

 I am doing my level 4 at the moment and as part of my planting selection and design have been asked to list the benefits and disadvantages of each of the following soils ameliorates when added to the backfill when planting a tree in a tree pit. The ameliorates are auxins, mycorrhizae, sugars, biostimulants and hydrogels (which are all mentioned briefly in BS8545 but without any pluses or minuses) plus any others I can add.

 

 I have looked online and can find what each of these is used for in relation to the tree but can’t specifically find anything on the benefits or disadvantages when added to a tree pit. 
 

 There is one article on the arb association website that specifically looks at peat but this is of little use. Everything else I find is basically saying there are no proven benefits to the amelioration of soil in tree pits so the only disadvantage I can really see is wasted cost. 
 

 If any one can point me in the right direction with this one I would be really grateful. As I have wasted at least 4 hours looking for something.

 

 I get the benefits of these things but not specifically in tree pits.

 

 Thanks in advance.

 

 Cheers Eric

[Dan Maynard]

I've heard of auxin as a rooting powder but not sure how it would work mixed with the soil. Seems it can inhibit root elongation if there's too much around, anyway.

[Thesnarlingbadger]

11 hours ago, Dan Maynard said:

I've heard of auxin as a rooting powder but not sure how it would work mixed with the soil. Seems it can inhibit root elongation if there's too much around, anyway.

Yes auxins are used for plant growth, they promote cell decision and in turn help with primary growth. But I can’t find anything out about them being used in a tree pit specifically. Or any other ameliorate either.

 I guess that might be what they are getting at is the roots will be stunted by excessive concentration of auxins and the shoots above ground grow more rapidly leaving the tree unsuitable. 
 

 Cheers 

[tree77]

Remember doing a similar module on my L6, there's wasn't alot of options from memory