The Inside Scoop on the Soil Beneath Your Feet

Recent scientific discoveries are shining a new light on soil, previously considered a dead medium merely required for plants to grow. Soil scientists, farmers, ecologists and biologists are learning more and more about the complex relationships between soil, soil microorganisms and plants. There is an old saying, “Good farmers make good soil,” and we are finally beginning to understand the science behind that statement.

First off, what are microorganisms (or M.O.)? In the soil they can be fungi, bacteria, mobile one-celled protozoa, tiny worms called nematodes, microarthropods, as well as earthworms, beetles, voles, etc.

According to microbiologist Elaine Ingham, plants send 40% of their carbon sugars to their roots where microorganisms feed in exchange for a mix of minerals. Fungi and bacteria secrete enzymes that liberate minerals from clay, silt, sand, stone and actual bedrock. There are soil bacteria specialized for certain conditions, better suited to thrive in different temperatures and moisture levels; as the temperature rises or during times of floods or droughts, certain populations of M.O. thrive and sustain the exchange of minerals in exchange for carbon sugars. Due to this symbiotic relationship, microorganisms often deter and defend plants against various attacks from pests or diseases because their food supply depends on the plants' health. This is a beneficial relationship with win-win results.

The M.O. and plant exchange also controls the underground flow of water and gases by building tiny structures called aggregates. Bacteria form tiny aggregates by catching a piece of clay, silt or sand and anchoring themselves there with carbon-rich glue, which they produce from the plant sugars. They do this initially to keep themselves from being carried away by water moving through soil, and as they glue themselves to other pieces of silt or decayed plant material, more comes into contact with them and a tiny structure forms. This protects them from predators and creates space for gases and water to pass slowly. The fungi gather up the bacterial aggregates and make their own slightly larger, lopsided aggregates. In healthy soil, there are trillion of these piled on top of each other. The aggregates form spaces that cup the water and are shared with all the life in the soil. This is why healthy soils have higher water absorption and retention, increased disease resistance and drought tolerance, as well as naturally healthier plants. In short, this means that less water goes further.

As an alternative to chemical fertilizers, compost and other organic material (debris), which evolved as a natural byproduct of plants, slowly break down in the sun, wind and rain and offer nutrients in a more spread-out timeframe. The plants are able to fully digest and benefit from the nutrients around them because soil microorganisms have enzymes, which make phosphorus and other elements readily available to the plant.

Suma Landscaping offers services to help rebuild the soil and microorganism population in the landscape:

COMPOST - We highly recommend the combination of compost and mulch for your garden. The compost replenishes minerals and elements to the soil needed for plant health; it is a natural and organic fertilizer.

MULCH - Mulch will help insulate the bare earth beneath plants and keep water from evaporating. We recommend covering the compost with mulch, which will enhance the natural beauty of your garden.

GRASS CLIPPINGS - There is a tremendous amount of nitrogen in the green of plant debris, grass clippings especially. During the non-rainy season, when the clippings are drier, it is beneficial to leave them on the lawn to recycle back into the soil. In some cases, these clippings can be used under the mulch in planter beds as well.

SOIL AERATION - While aeration does not aid microorganisms, it does improve the garden’s ability to absorb the water you are applying and reduce water run-off.

ADDITIONAL OPTIONS - Although it may not be practical for Suma to provide compost tea or onsite composting for you, these additional horticultural practices can be beneficial for your soil. Please contact Suma if you would like more information about how to do it yourself, or if you would like us to help formulate a plan for your garden.

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