The more you know about the structure of your soil, the better you can help it support your plants.
Soil doesn’t exist in isolation. Except for sand, soil is a combination of minerals, air, water, microbes, earthworms, and more. Soil structure refers to the particular arrangement of these combined particles. These clumps of different particles are called soil aggregates. Aggregates contain solids and spaces and are held together by organic matter in various stages of decomposition, earthworm and insect poop, and chemical excretions of nearby plant roots.
While soil types may not look terribly different to the naked eye, at the microscopic level, where root hairs, microorganisms, water and plant nutrients are moving around, the soil structure is really important. Soil structure should not be confused with soil texture, which is based on the percentage of silt, clay, and sand. Soil structure is about how everything is arranged into clumps, or aggregates. Soil structure is caused by several factors:
Types of soil structure
The fundamental components of soil, sand, silt or clay, have a lot to do with the overall structure of your soil. Obviously, clay is far more likely to become compacted than sand. The clumps of material that make up soil are called aggregates. Soil aggregates are categorized by their size, shape, and stability. There are eight soil structure types:
The large and small spaces between soil aggregates, called macropores and micropores, respectively, determine soil porosity, permeability, and water-holding capacity. Soil structure can be damaged by digging, rainfall, and heavy traffic, which all destroy those important spaces, causing compaction. Instead of loose collections of many different sized aggregates, crusts form along cut edges or on top of the soil, blocking the flow of water, air, and nutrients, and making it difficult for seedling roots to take hold. It’s not very fun to work with, either. Good soil structure can help move water away from roots when over-watering occurs and it allows plant roots to go where they need to go, for food and water.
How to build good soil structure
Nature has been making good soil for a really long time. Plants, insects and animals die, and then their bodies break down into nutrients that are watered into the soil. Then microorganisms and soil-dwelling animals, insects and worms eat those nutrients and poop out the stuff that hold soil particles into various sized aggregates. Because many of us live in homes where construction soil is common, we must recreate the natural cycles needed to maintain healthy soil structure. To maintain good spacing between aggregates, especially for clay soil, use these tips:
Healthy soil produces healthy plants that are better able to fight off pests and diseases on their own.
You can grow a surprising amount of food in your own yard. Ask me how!