Basic Soil Information

Soil is composed of air, water and organic matter.

Soil is made up of mineral particles, water, air and organic materials. Each of these ingredients makes a contribution to the soil's overall structure and ability to sustain life.

Porosity

The larger a soil's mineral particles, the greater the space between them. Large particled sandy soils have high soil porosity, or space between particles. Highly porous soils are well draining and aerated. Clay soils have low porosity. Clay soil is often compacted and airless, resulting in pooling surface water. Loam soils have optimum porosity. Loam is capable of retaining water and allowing air to circulate. Growers strive to improve their soils to this condition.

Texture

Sandy soils are gritty while clay soils are sticky and wet. Loam crumbles in your fist and has moisture levels similar to a wrung out sponge. Clay soil texture can be improved by adding sand. Sandy soil texture can be improved by adding organic matter.

Organic Matter

Organic materials such as compost break up dense clay soils and increase porosity. Compost is applied to loam after a growing season as a way to maintain the soil's composition. Poor, sandy soils use compost as means to increase their bulk. This allows them to retain moisture and nutrients.

References

• Purdue University Consumer Horticulture: What Is Loam?