Environmentalism, Conservation, and Sustainability:
Part V: Talking Dirt

Environmentalists often speak of soil as it pertains to contamination from chemical by-products from manufacturing and farming; but soil is often overlooked as an important commodity when speaking about conservation and sustainability. All life depends on the soil. Earth’s soil is essential for food production. To raise the crops we consume and feed to livestock, we require high-quality soil. Soil is also vital to wild-growing plants. Many other types of environmental protection, such as plant preservation and animal protection, are based on soil conservation.

Soil degradation can be traced back to many causes including over-use, erosion, salinization, and as mentioned before, chemical contamination.  Slash and burn clearing methods cause deforestation, loss of soil nutrients, and erosion on a massive scale.  Soil erosion strips away topsoil that contains organic matter, nutrients, and microorganisms essential for plant growth.  The topsoil ends up being flushed into aquatic resources causing contamination from pesticides and fertilizers used in farming.

Monoculture, such as repeating the same crop in the same spot, depletes soil nutrients. When farmers plow up and down hills, soil erosion by water and wind increases.

There are many natural and holistic strategies that can be used to lessen erosion, increase soil fertility, conserve moisture, and neutralize acidic soil.

Contour plowing is an effective way of farming on slopes that prevents runoff and increases crop yields. Keyline design is an enhanced version of contour plowing that takes into consideration watershed properties when plowing.  Topographic features are taken into consideration so that water runoff goes back into existing water channels thus preventing soil erosion.

Contour strip cropping is one type of soil conservation strategy. Crops such as corn, wheat, and clover are all grown in a field together in alternating strips across a slope or down the course of the prevailing wind. Various plants with various root systems and leaves aid in the prevention of erosion.

Terrace farming involves carving multiple flat level steps or terraces into hillsides.  Each step is surrounded by a mud wall that prevents runoff and keeps nutrients in the planting beds.  Another method of preventing runoff is planting trees, shrubs, and ground cover around the perimeter of the farmland.  Other methods such as no-till farming also help with soil conservation.

Rows of tall trees provide windbreaks preventing wind erosion. Stream banks can also be protected by planting trees or constructing walls.  Reducing paved areas around fields helps to prevent runoff.  Runoff can be collected to create rain gardens and prevent erosion.

Cover crops can be rotated with cash crops to help produce green manure that replenishes soil nitrogen and other nutrients.  Agrostological measures involve planting grass in rotation with regular crops to increase the nutrients in the soil.  

Other forms of soil conservation farming mimic the natural biology of virgin land. This can involve planting indigenous crops that have a natural need for the soil already in the area and using indigenous microorganisms. Eliminating the use of nitrogen fertilizer and fungicides helps to increase yields and protect crops from drought and flooding.  Also, in areas where there is little water, only planting crops that thrive in this environment is important.

Controlling salinity, acidity, and mineral depletion can be achieved in different ways.  Humic acids are used for soil salinity management. Crushed rock can be added to combat mineral depletion.  pH levels in the soil should be monitored and only eco-friendly chemicals used to control soil acids. Liming also neutralizes the acidity in the soil.  This can be done by carefully adding calcium or magnesium-rich materials like limestone, chalk, or marl in the correct amount. 

Earthworms can be a big savior to the soil, as are many natural microorganisms.  These microorganisms can be enhanced by planting the right trees, the right crops, and using the right fertilizers.  Excess chemical fertilizers can poison the soil rather than keeping it fertile. 

The chances of losing productive soil to wind and water erosion are increased when trees are harvested from a wide area, which is known as clearcutting. Selective harvesting, the selective removal of individual trees or small groups of trees, is an alternative that leaves other trees behind to anchor the soil.

Sharing knowledge of Agroecology is important between countries to improve soil fertility and prevent famine in many parts of the world.  This holistic approach uses natural processes to bring together agriculture and local communities benefitting both nature and livelihoods. 



September 19, 2023 — Debby McKnight