What Is Soil Structure?

Here at Sunday, we’ll help you care for your whole yard ecosystem, not just above ground but below it too! And that starts with soil. Healthy soil helps cultivate healthy plants. While our soil test can tell you about the nutrients your soil holds, it doesn’t tell you about your soil’s physical properties such as color, texture, and structure. Maintaining the structure of your soil goes hand in hand with caring for your yard’s health.

What is Soil Structure?

Soil is made up of particles that were originally different mineral rocks that have been weathered over time into small pieces. These particles vary in size, shape, and chemical composition. There are 3 categories of soil particles:

  1. Sand (largest)
  2. Silt (medium)
  3. Clay (smallest)

 

The combination of these particles forms your soil’s texture. Having a pretty good mix is important for drainage and aeration, and allows nutrients and organic matter to move freely and evenly through the soil. More nutrient absorption = more plant growth!

Soil structure refers to how these differently textured particles group and bind together, along with organic matter and plant roots, to form aggregates and peds.

  1. Aggregates: These are basically clumps of sand, silt, and clay that vary in size and shape and are influenced by human interventions like tilling, walking on the soil, and fertilizing.
  2. Ped: Peds are aggregates that occur naturally in the soil without any help from outside factors but rather through soil formation processes that take into account place, environment, and history of the land.

Why is Soil Structure Important?

Like humans, plant roots need water and oxygen to survive. If your soil is too compacted or too loose, it’s harder for roots to get what they need—but that just-right soil structure allows for more water intake (and retention) and oxygen flow.

Good soil structure makes it easier for plant roots to grow by helping:

  1. Water intake. Pathways are created by soil aggregates that allow water to move through the soil.
  2. Fight compaction. Healthy soil structure ensures good airflow in the soil, keeping it from becoming compacted.
  3. Oxygen flow. Increased porosity from good soil structure lets oxygen into the soil which is essential for supporting soil life and plant growth.
  4. Carbon sequestration. Good soil structure increases carbon storage in the soil, taking it out of the air.

Combined with deep and infrequent watering and targeted nutrient applications, good soil structure will keep your yard happy and healthy.

What Destroys Soil Structure?

While it’s important to understand what builds your soil structure, it is equally important to know what destroys it. Compaction forces aggregates together, removing pore space, while high sodium levels, excessive handling, and overtilling impair soil structure by breaking up aggregates.

How to preserve your soil structure:

  1. Minimize handling or disturbance of the soil.
  2. Reduce bare spots. Seed in clover or diverse blends of grass, add native ground cover, or add mulch where grass might not grow. 
  3. Incorporate organic matter to encourage microbial activity.
  4. Limit traffic to avoid compaction. 
  5. Grow deeper grass roots with proper watering and mowing practices

How Sunday Helps Your Soil

Our focus on addressing nutrient deficiencies, building organic matter, and using biostimulants (like molasses and soy protein) will contribute to forming aggregates, so your Smart Lawn Plan is actually helping build healthy soil! 

 

Healthy soil = healthy yard = happy you.

Cited Sources

University of Hawai’i at Manoa. Soil Texture and Soil Structure

Plant & Soil Sciences eLibrary. Soil Structure