Since the beginnings of agriculture, we have understood that adding composted materials to the soil helps our crops grow. As time has gone on, we’ve peered though microscopes, seeing hidden worlds of life in our soils. We now know that dark rich compost is more than just rotten kitchen scraps and manure. Living in the humus, or non-living organic components, are bacteria and fungus physically and chemically breaking down plant matter. The humus also houses microscopic worms and protozoa competing for resources, eating each other, and in turn becoming another link in the food web. This soil food web is what creates the nutrients that plants require, and it forms healthy soil structure.
But there’s more… plants produce specific simple sugars in their roots (called exudates) that are chemical signals for the bacteria and fungus living in the soil. They are literally calling out to their environment asking for what they need. It might be a specific form of nitrogen, a bit of carbon, or some trace elements like calcium or magnesium. Incredibly, when the fungus (called mycorhizzae) receive (or eat) these signals, they go to work to bring the plant what they need. The fungal network can stretch for acres and acres, bringing nutrients to the plant from hundreds of feet away (and more!). It’s a system that soil scientists and ecologists are beginning to understand; however, they also realize they are just scraping the surface on how much communication and teamwork is really happening beneath our feet.
This is a video featuring Dr. Elaine Ingham discussing the importance of the soil food web, and the massive benefits of creating healthy living soil.