Soil is a complex part of the living landscape. A natural soil takes centuries or millennia to develop. Precipitation, temperature, plants and animals, landforms, and geologic material (bedrock, glacial deposits, river sediments, etc.) all influence soil development over time.
Every plant requires different soil conditions to do well, yet we sometimes take them for granted and assume plants will grow in any soil. Soils can vary considerably, however, especially those that have been disturbed by human intervention, and this impacts a plant’s ability to survive. What is optimal landscape soil? This will depend on the plants being grown and the conditions they require to do well.
These are some of the functions that soil performs:
- Reservoir for plant nutrients and water
- Habitat for bacteria and fungi that break down organic matter
- Habitat for insects and other animals that mix the soil
- Medium for anchoring plant roots
Many tree and shrub problems in urbanized areas can be traced to changes in the physical or chemical aspects of the soil. Grading and associated construction activity can quickly alter the natural soil environment and disturb roots. Understanding the effects of these impacts on soil and plant health, and learning how to improve them, will enable gardeners and landscapers to more wisely maintain the soil and its environment.