Brower Park’s Nature

The Natural Elements that Make Brower Park Green

SOIL

All living things experience stress. Soil, a living ecosystem of organisms, organic and inorganic material, is affected by changes in its environment. Plants, dependent on the soil for a supply of water and nutrients will also be affected by environmental changes.

What is soil?

Soil (top soil) is a thin layer of material that is on the Earth’s surface in which plants have their roots. It is made up of weathered rock (minerals) and decayed plant and animal material (organic) and forms over a long period of time. Healthy soil contains 35% to 50% air and water and more air than water. Sand particles are in the majority followed by silt then clay. About 5% of the organic material in soil (plant and animal) is comprised of living organisms, living plant roots, dead organisms and plants in various stages of decomposition.

What is in the soil?

  • Sand particles–lightweight soil, that is free-draining but cannot hold nutrients.
  • Silt particles–holds water, can be difficult to drain; holds a limited amount of nutrients.
  • Clay particles–holds water but can become heavy and waterlogged when wet; can hold onto nutrients.
  • Water–clings to soil particles (silt,clay) allowing plant roots to drink.
  • Air–fills gaps in the soil allowing plant roots and animals to breathe.
  • Organic matter–includes plant roots, dead plants, dead and living organisms, manure, leaf mold and compost that releases nutrients into the soil slowly as it rots and improves water holding capacity. It helps hold the soil together.
  • Animals–insects, bacteria and earthworms that help to break down organic dead matter.
Brower Park Lawn Showing compaction caused balding

Brower Park Lawn showing the effects of compaction and consolidation.

Images of well aerated soil and compacted soil

An example of Aerated soil vs. Compacted soil.

What is meant by soil compaction?

  • Soil compaction is the process in which a stress applied to the soil causes densification as air is displaced from the pores between the soil grains.
  • Soil consolidation occurs when water is displaced from the pores between soil grains.
  • Stress is caused by heavy equipment or heavy animal footfalls on the soil. According to Nina Bassuk of Cornell University “Soil compaction is the single most difficult and harmful environmental or abiotic condition that a tree or shrub can experience.”

What are the consequences of soil compaction to plants, shrubs, and trees?

  • Affected soils are less able to absorb rainfall, increasing runoff and erosion.
  • Plants have difficulty in compacted soils because the mineral grains are pressed together, leaving little space for air and water, essential for root growth. Highly compacted soil cannot support the microorganisms and earthworms that are essential to a healthy soil–aerated and nutrient rich.

What methods are used to lessen soil compaction?

  • Replacement of current soil–considered a drastic and expensive solution that is usually applied only to small areas.
  • Add two to four inches of topsoil for grass reestablishment. Trees can require eighteen to three feet of new soil. The larger the plant the greater its demand for water requires a greater area of aerated soil.

What methods can be used to provide drainage and aeration to newly added soil?

    Below the newly added soil may be layers of poorly draining soil that can force water into the plant root zone. Using a technique of sub-surface soil sculpting may be used to grade the layer in a way that moves excess water away from the planted area. In one technique water is channeled through swales or drains via gravity.

How can soil compaction be prevented?

  • Wet soil is weak soil. Don’t walk on a lawn, garden bed or tree pit when the soil is wet.
  • Create permanent paths using gravel, wood-chip mulch, or stepping stones that allow weeding and care without stepping on the soil.
  • Add organic material such as mulches, manures, and home made or store bought compost to the soil. The added organic material encourages earthworms and microorganisms that will improve soil structure, drainage and lessen compaction.

References

  1. Department of Horticulture at Cornell University–Gardening Home
  2. Colorado State University Extension, CMG Garden Notes. Download the PDF.
  3. USDA Natural Resources Conservation Service–Soils
  4. USDA Soil Health
  5. Life Under Your Feet

Compost

Compost Creatures Big and Small.

Temperature, moisture, air, and the diversity of organisms determine the

Bacteria

Bacteria are the major decomposers in a compost pile. Bacteria require nitrogen to reproduce and use carbon as a source of energy. Some bacteria give off energy as heat causing the temperature of the compost to rise. The earliest colonizers of the compost pile are psychrophiles who work best at around 55 degrees F.

References

 

Sustainable Gardening  Websites.

Last Frost Date

National Climatic Data Center

Cornell Garden-based Learning

Organizations working toward preserving our natural resources, our natural world and a sustainable planet.

Monarch Watch
The Xerces Society
National Wildlife Federation
National Wildlife Federation Plant Finder
National Geographic