Tuesday, May 10, 2011

Becoming Good Stewards of Our Soil

I often have this recurring thought: before our man-made fertilizers and pesticides and herbicides and fungicides, how did things grow and thrive without our help? Where did plants get their nutrients? How did they protect themselves from predators? The answer to all of these questions has to do with soil health.

I'd like to think that if we better understood how things work in the soil, we wouldn't use oil-based chemicals so freely and we would certainly question the practice of tilling. Healthy soil that is teeming with life - bacteria, fungi, nematodes, anthropods, protozoa - have a function to play in plant nutrition and defense.

Plants excrete a substance called exudate - akin to human sweat - which attracts beneficial bacteria and fungi in the soil. Bacteria coats the roots of plants leaving no room for anything else to attach, which helps to trap unwanted pathogens. Fungi create a protective web around a plant's root, creating a physical barrier against invaders. Other fungi provide nutrient delivery in exchange for food. Still others produce vitamins and antibiotics to maintain or improve plant health.When we till or spray chemicals, we destroy this important symbiotic relationship.

Tilled soil - what not to do. Photo by Michal Marcol.
Healthy soil produces nutrients for plants, and plants themselves recycle their own nutrients when they shed their foliage each fall. Healthy soil is full of soil organisms and all of which eventually die and decay or are eaten and excreted. Nutrients are created in this waste, consumed again, broken down and made available to plant roots continuously through this cycle. When soil is sterile, we are required instead to add inputs from chemical sources to supplement what is no longer a self-sufficient system.

Soil with living organic matter is full of tunnels and pockets and holes made from all of the organisms traveling within. These spaces allow the soil to absorb rainwater while minimizing the leaching of nutrients, provide soil structure so that the ground does not compress and loose fertility, creates transportation highways for nutrients and soil life, and allows air circulation necessary for biological activity. Soil organisms also excrete sticky substances to help bind soil particles together. When our soil is damaged, life cannot be supported, nutrients and top soil are washed away in heavy rains and flooding results.

Healthy soil is necessary to produce healthy plants, and healthy plants are necessary for healthy life of all kinds. We cannot ignore this web of life, which serves such a vital function. When we damage the soil, we are ultimately damaging ourselves. Truly sustainable agriculture is only possible if we look to the origin of the problem, which is how we care for our soil and the life within. We can all contribute to the solution. The first place to start is by becoming good stewards of our own front yards, back yards and garden plots. Stop spraying, stop tilling, start composting and help the life within your own soil to flourish.

Teaming With Microbes, by Jeff Lowenfels and Wayne Lewis

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