I am in the process of doing a geological assay test where they tell me what is in my parent material. Then I know if anything is truly missing that will need to be regularly supplemented. But it will not let me know if what is present is in plant available form. Over this first season the physical properties of my soil have improved significantly, much darker crumbly soil, far less compacted, and starting to get a lot of earthworms now. I do not think I am low on NPK but I do think I am having some other nutrient or micronutrient issues. I have ordered the book Mineral Nutrition and Plant Disease and I am hoping to be able to sort out any deficiencies faster next season, and supply via a foliar. I have to say I have many crops that I have never seen look as good as some of the crops I had this year, so it is a teaser for me to keep going with the biology-compost at this point. And for this next season I have a manganese, iron, boron, zinc, sulphur, copper, humic acid foliar that I plan to use early season and then as needed for through the season. But I do agree with you that each compost pile will be different, I guess my hope is that if I can make it though the next year and keep a crop in the ground at all times, that once I get a reasonable stable soil organic matter and good AM Fungal population, the system should be able to deal with slight changes… I am a bit of a naturalist at heart and I keep holding out hope that nature is capable, with local diverse resources composted for fertility – but yes it could be a bit of a pipe dream. I guess the mother in me, weary of the future, also deep down wants to figure out how soil improvement and plant fertility can be accomplished with only local inputs. But reality is reality and we all need to make a living so always need to have Plan B in mind.