Fall is a great time to think about soil health

IDAHO FALLS — Fall is a great time to think about the soil. As gardeners we should always consider the health of our soil in everything we do.

The five principles of soil health are:

• Cover the soil—leave crop residue on the soil and let the microorganisms work it into the soil.
• Minimize soil disturbance—reduce tillage.
• Plant diversity—almost like nature would do it.
• Continual live plant/root—if something can be growing something should be growing.
• Integrate animals—it’s more than just manure.

I recently read a book that indicated we know more about life in the ocean than we do about life in the soil on which we walk. There is an extremely diverse ecosystem in the soil. There are more microorganisms (microbes) in a teaspoon of healthy soil than there are people on the earth. These microbes include bacteria, yeasts, algae, microscopic insects, nematodes, earthworms, macroscopic insects, mites and fungi. Scientists are still trying to figure out how to classify many of the soil microbes. Only a few of these microbes would be considered harmful, and in a healthy soil the beneficial microbes crowd out or consume those that are harmful.

What do these microbes do?

• Bacteria—feed on organic matter—particularly compost, store and cycle nitrogen, decompose pesticides.
• Fungi—feed on tougher organic matter—like wood and bark, extend the reach of roots and act as a transport system to get nutrients to the roots, hold water for the plant.
• Protozoa—eat bacteria, fungi and algae, unlocking nitrogen.
• Mites—decompose and shred organic matter.
• Nematodes—eat other organisms in the soil as part of the nitrogen cycle.
• Earthworms—consume and expel minerals and organic matter, creating nutrient-rich casts; create tunnels that help air and water movement.
• Macroscopic insects—feed on other soil microbes, shred and decompose gross organic matter.

All the microbes in the soil ecosystem work together to create a strong and resilient soil structure.

Principles of soil health graphic from USDA Natural Resources Conservation Service website.
In the home garden we can easily incorporate the first four principles with the goal of improving soil health. Gardens will be more sustainable if we focus on feeding the soil rather than feeding the plants.

When we focus on soil health the soil structure improves, drought resistance improves, water infiltrates faster (less flooding and runoff), nutrients are cycled more efficiently, soil organic matter increases, more carbon is sequestered in the soil, erosion is reduced, plants are more resistant to insect and disease pests, and the food we get from the plants has higher nutrient density (not sure how they measure that, but homegrown does taste better).

I will cover the five principles of soil health in future articles.