Hana Kirk

Soil Structure, Soil Texture and Soil Types


Soil is integral to life on earth, as it filters water, enables growth of forests and crops, and most importantly it regulates the earth's temperature and greenhouse gases.

We know that soil matters, let's dig deeper to find out why...

Soil is integral to life on earth, as it filters water, enables growth of forests and crops, and most importantly it regulates the earth's temperature and greenhouse gases.

Soil is the skin of the earth and is a dynamic interface between terrestrial ecosystems, linking:

  • bedrock (lithosphere)
  • air & climate (atmosphere)
  • water (hydrosphere)
  • all living things (biosphere)

This dynamic interface functions due to an ‘underground livestock’, which in conventional farming practices has been ignored - maybe because we cannot see it with the naked eye or because it's under our feet?


The ‘underground livestock’ are the soil microorganisms: bacteria, actinomycetes, fungi, algae and protozoa, along with a host of soil invertebrates. Soil biology, plants and terrestrial creatures have a symbiotic relationship, and one cannot be healthy without the other. By providing food (organic matter) and a home (air and water) for the ‘underground livestock’, the terrestrial ecosystems can work together to build soil health which improves plant health and therefore human wellbeing.


Soil Type definition: soil type is the ratio of sand, silt and clay – the mineral particles in soil which are derived from rock, broken down over thousands of years by climatic and environmental conditions (rain, glaciers, wind, rivers, animals etc.). At Soil Matters we classify soil types as:sand, loamy-sand, sandy-loam, sandy-silt-loam, silt, silty-clay-loam, clay-loam, sandy-clay-loam, sandy-clay, silty-clay, clay, and peat.

Soil Texture definition: soil texture is the mineral particle size in the soil and is directly related to the soil type. At Soil Matters we classify soil texture as:fine, medium or coarse.

Soil Structure definition: soil structure is the arrangement of solid soil particles (mineral and organic matter), grouped together in aggregates depending on the shape, size, strength, and extent of adhesion to another. The extent of adhesion is influenced by physical, chemical and biological processes. Organic matter and plant roots are therefore key to soil structure. The shape, size and strength of aggregates determine pore structure, soil water holding capacity, and how easily air, water and roots move through the soil.

The pie chart above/below shows an estimated physical composition of undisturbed soil having ~50%pore space and ~50% soil solids. Pore space can be increased by using plant species with varying root depths. It is also possible to decrease pore space when soil cultivation causes compaction. To minimise soil disturbance and maintain soil pore space and soil structure, careful consideration of management techniques used with cropping, grazing, cultivation, and water usage etc. is vital.


Minerals have specific biochemical functions for plants and microbiology. For example, calcium is a structural component of the cell wall in plants. In fungi, plants and bacteria, calcium helps to regulate internal chemical processes. Minerals can of course be applied to the soil; however, they often also exist naturally in the sand/silt/clay composition of the soil.Soil biology can mobilise natural minerals from the existing soil into a plant-available form (once again another great reason to keep your ‘underground livestock’ alive and happy). Water is a solvent and a carrier for plant nutrients, so pore space is crucial to ensure nutrient availability.

As each mineral has a specific function in the soil ecosystem, we cannot assess minerals individually. We need to view the system as a whole and aim for the correct balance.

Here at Soil Matters we get excited about soil as it truly does matter, and we aim to share our knowledge and enthusiasm with you too!

Hana Kirk
Product Manager

Fun fact:

Justus von Liebig is the discoverer of the effects of nitrogen on plant growth. In his early days he was a profound promoter of the use of nitrogen to enhance plant growth. However, what is often forgotten about is that at an older age he discovered new insights and learnt that the unlimited use of nitrogenous fertiliser does not come without consequences. We have an English translation of his diary available in which he describes the journey of his learnings. Feel free to get in touch and we will get you a copy!

Contact us for a quick yarn about how we can help your farm

Phone 0800 764 5628
Call us!

When you work alongside a Soil Matters specialist, first we’ll tee up a farm visit so we can get to know each other, and to learn what your goals are for your farm. Next we’ll gather the relevant information to assess the health of your soil (you can start with a specific area or we can do a whole farm assessment). Then we’ll take this information, and together with the other experts in our team as required, we will look to identify any factors which could be limiting your plant growth and put a plan in place!

One of our team will be in touch!
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