Science underground

Bacteria break down dead organics releasing nutrients in a form that roots can absorb. Why do they do this? Because they get carbohydrates obtained through the action of photosynthesis and delivered to the roots which secrete this substance. This is the rhizophagy cycle and you probably already know something about his because for the past few years we have been discovering different mycorrhizae fungi whose hyphae bring water and nutrients to plant roots while receiving carbohydrates in return.

In this instance, root cells absorb microbes and blast them with superoxide. This degrades the cells of some of the microbes which releases nutrients that the plant needs. Some of the microbes survive and are released at the root hair tips where they go back into the soil to pick up more nutrients in this elegant cycle. Even more interesting is that while this is happening, the microbes are helping to suppress pathogens in the plant cells.

This is not the end of the story or the only thing happening down here – just one of the latest discoveries. Deeply rooted weeds such as Canada thistle and dandelions bring nutrients up from the depths to the surface. Earth worms of all kinds also do a very good job of mining nutrients so that they are available for plants. They are also the first processors of the vegetative or organic matter you leave or incorporate into your garden. The materials they ingest as they burrow is chemically changed so that their castings are much more digestible by plants and other organisms. There are millions of other insects and other organisms, each of which does its part.