Soil Structure & Texture

Soil Structure

• Soil structure refers to the way that soil particles are combined into aggregates. There are five basic types of soil structures. Granular soils are optimal for plant growth, since the particles are loose but also retain water well. Other soil structures include platy soil, blocky soil, prismatic soil and structureless soil. These soil structures are less beneficial for plant growth, since they provide less efficient water retention and aeration to plant roots. Soil structure is usually easy to change through cultivation practices like tilling.

Soil Texture

• Soils textures are commonly described as sandy, silt, loam or clay. Whereas soil structure refers to how the soil particles are put together, soil texture refers to the type of particles that make up a given soil. Sand particles are large and porous, whereas clay particles are very small and tend to stick together when wet. Loam soil contains an almost equal balance of sand, silt and clay and is ideal for most plants.

Common Problems

• Soil structure and soil texture can present problems for gardeners and farmers. Clay and sand soils may not be able to support plant growth, depending on the types of plants in your garden. Clay soils retain high amounts of water, which can cause root rot and other diseases. Sandy soils have the opposite problem. The large amount of space between soil particles causes them to drain quickly, which can cause drought-like conditions.

  Soil structure can also present a variety of gardening challenges. The most common problem with soil structure is compaction. In compacted soils, the particles have been pressed together, usually into a platy structure, which does not allow water and nutrients to penetrate to plant roots. Soil compaction is often caused by heavy farming equipment, and may also occur in soils that receive heavy traffic.

Good Practices

• Organic matter improves most types of soil, since it fills in the gaps between large sand particles and increases the space between dense clay soil particles. Compost, manure and peat moss are a few examples of organic matter. As with any soil amendment apply organic matter moderately, since excessive amounts may cause salt buildup and other problems. To avoid compaction, never till the soil when it is wet, which may increase the stickiness of soil particles.