Assigning polygon layer attributes to point layer features in QGIS

I have a task which I’m sure is quite common, but being new to QGIS I’m hoping someone can point me in the right direction. I have a point layer with PLANT_ID and SPECIES of individual plants, and three polygon layers: SOIL, DRAINAGE, and CANOPY. For each individual plant, I would like to add three attributes, one for each of the three polygon layers. The result would be something like this:

So for this example, Plant 1 was Species A, and it was located in a SOIL polygon with attribute Soil 1, and was located in a DRAINAGE polygon with attribute Drainage 4, and was located in a CANOPY polygon with attribute Canopy 4. I suspect that this has something to do with a Spatial Join in MMQGS, but I've played around with that and was not able to get what is shown in the table above.

Beyond this, I was planning to apply some data mining techniques to create a decision tree like this:

If SOIL 1 and DRAINAGE 2 and CANOPY 3, then SPECIES D

Might there be a QGIS function that would create this type of tree?