I am interested in brushing up on soil organisms and their roles in the nutrient cycle. Specifically, I'm interested in how various organisms interact with minerals, organic matter, and other life forms in the soil, and during their life cycles, how and what nutrients they make available to plants...nutrients that might otherwise be locked up (or unavailable). Also, it is my understanding that some of the more well known and necessary nutrients, even if present in the soil, may still be unavailable to the plants if certain trace minerals are absent, or in insufficient or excessive quantities.
If anyone has any thoughts on this topic that they would like to share (or recommended books, videos, articles, etc.), I would love to hear about them.