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Garden Soil Structure: Why It Is Important

January 27, 2022

Soil Structure is A Key To Healthy Plants

Soil texture and structure are the most important criteria for the success and health of your garden and landscaping. The porosity and soil makeup affect its water retention and movement, ability to provide air to the roots, ease of root growth and the absorption of nutrients. Very few gardeners consider the soil’s structure and focus more on its texture (Soil Texture Article). In fat, soil structure can vary greatly within soils that have exactly the same texture. A clay soil can be porous, with gaps for air and water, or can be resistant to root growth and any type of retention.

What exactly is soil structure?

I like to think of soil structure as the way to small particles bind together, or their affinity for aggregation. In fact, the technical term for their grouping is aggregates or peds. The particles are bound together by physical, chemical and biological properties. Physically, as roots grow they displace soil and bind and compress. Chemicals in the soil, like calcium, magnesium and aluminum are positively charged and and bind other chemicals. And one of the most important factors, is the biological binding provided by bacterial and fungal excretions and the sugars and elements excreted by roots.

Types of Soil Structures

The type of structure is defined by the shape, size and “stickiness” of the aggregates. Here are the types:

  • Granular
  • Aggregated
  • Blocky
  • Columnar
  • Platey
  • Massive
Structure Types from USDA

What Negatively Impacts Soil Structure?

There are a variety of forces that can adversely affect and impact your soil structure:

  • Compaction
  • Cultivation
  • Removal of vegetation
  • Excessive moving and handling of soil
  • Screening
  • Excessive sodium

How Do you Maintain a Healthy Structure?

A healthy soil structure is maintained through the fostering of the soils biomass. Adding bio-matter and compost, avoiding compaction and the use of mulch can foster healthy soil.