How can I add extra information for each term reference? I'm trying to create a content type that matches a product. The product can be made of several thing in different percentages:

Eg.

material 1:
    material 1.1: 5%
    material 1.2: 0%
    material 1.3: 20%
material 2: 75%
material 3: 0%
material 4:
    material 4.1 0%
    material 4.2 0%


I've built the materials hierarchy using taxonomies.
How can I add a parameter to a taxonomy so I can do this?

I've tried using Field Collection, but the problem I encountered was the inability to work with Solr
There are two options:


Create own module based on taxonomy. Most flexible, but also most complicated. That's what I would do, if I had time and motivation to play.
Use Field collection - create a collection of term and percentage fields, and make this collection (not individual fields in it) multivalue. Warning: I know of no easy way to make sure your percentages adds up to 100%. I know how to do it easily in custom module.... see point 1.