Radiant Bunny Tests the Soil
But, if you want to get complicated, then do what Radiant Bunny does. Test the soil. You'll get complicated, web-of-life style.
Radiant Bunny can think of two categories of testing soil, the DIY Soil Test Kit method and the ask-a-testing-lab-to-do-it method.
the DIY Soil Test Kit method
So many kits to choose from. This might take some time to read-up and understand the different options.
the ask-a-testing-lab-to-do-it method
Here is a place. Check it out. UMass Soil and Plant Tissue Testing Laboratory and they have a list of services covering all of the different tests.
Hey, look, a compost test.