For you Permies.
Nitrogen A to B or; Above & Below
1. Get the flowering and fruiting seasons of local native legume species.
2. Source and identify species of interest using flower ID and information.
3. Harvest seeds when season arrives.
4. From the same plant, at or just out from the drip line if it is a shrub or tree, uncover and remove a portion of nodulated root matter. Most legumes are hard as nails, but be sparing/careful with rare plants. Younger plants are easier to retrieve nodules from.
5. Check a nodule for colonisation. Slice it in half. Larger helps distinguish between: If you have a cream to brown even tending to orange color in the nodule, it's probably not inoculated. But a purple through to reddish color signifies nitrogen fixation taking place.
6. Shake out excess dirt and put root materials in a plastic bag then on ice. Then in your freezer.
7. Get local instruction concerning growing your local seeds to time next step.
8. Thaw root materials and dissect out nodules with a clean blade, wash nodules thoroughly in water.
9. Grind nodules to paste and dilute with de-chlorinated water, use slurry in process to wet media e.g. soak into some peat, for your seeds.
10. Plant seeds.
I've not investigated the symbiont coating the seed (9) part of it very well yet. The peat is a mycorrhizal trick I like.
It would be nice if a maker of seed balls chimes in and help inform this part of the process for wild and STUN plantings.
The above will get you both nitrogen fixers and practically guarantees the symbiont, if present, is correct = Free Nitrogen.
If only everyone was as easy to teach as Permies, you folks with your quaint knowledge and such.
May hordes of microbial chemists enrich your landscapes with their bounty. Free nitrogen for all!