What are the environmental benefits of composting?

Compost is a key ingredient for improving our coastal and marine ecosystems and waterways, and it all starts with using the soil amendment on land. Living in an island community, we can directly see how our actions on land impact coastal waters, whether there is a beach closure due to high bacterial levels, algal blooms from excess nutrients in waterways, or finding litter in parks or on beaches – the act of composting and the use of finished compost can directly address all of these environmental issues beginning right in our backyards.

Let’s start with looking at our watershed – when water enters the watershed via precipitation, it is either absorbed by green spaces or runs off the land in excess, also known as stormwater runoff. As water runs off the land, it collects anything in its path - oil from vehicles, bacteria, nutrients from chemical fertilizers, and litter. All of these pollutants make their way into the storm drains that flow directly into our surrounding waterways.

What happens if we add compost as a soil amendment into our watershed? Compost…

• ➔ Acts as a Natural Fertilizer.

  Healthy compost reduces the need for chemical fertilizers and pesticides. Adding compost to your soil beds adds organic nutrients slowly over time as the compost decomposes, reducing the need of extra fertilizers. Chemical fertilizers need to be constantly reapplied each season. Compost is made up of nitrogen, phosphorus and potassium, which are essential nutrients for plant growth and ensures that food grown in that soil-compost mixture is nutrient-rich, promoting human health as well.

• ➔ Enhances Soil Infiltration Rate.

  Using compost as a soil amendment increases the infiltration rate in soils, meaning that the soil has a greater capacity to absorb water and nutrients. The more permeable and porous our soils are, the greater capacity for water absorption which increases plant growth and feeds the soil microorganisms.

• ➔ Decreases Stormwater Runoff.

  The dynamic mixture of organic matter and soil aiding in steady water infiltration rates is also important for reducing stormwater runoff. Stormwater runoff exists when the ground is unable to absorb all of the water in the soil, causing the excess water to drain from the surfaces into the nearest water bodies. Unfortunately, stormwater runoff carries many pollutants, contributing to greater water quality issues for fresh and saltwater bodies.  Having healthy soil mixtures in yards, parks and agricultural spaces can help to reduce stormwater runoff in watersheds and can improve water quality. Increasing green infrastructure projects that use compost and help to retain excess rainwater are also great solutions.

• ➔ Reduces Erosion.

  Erosion is harmful for the environment as it physically alters land composition and increases sedimentation levels in waterways, contributing to larger water quality issues. Using compost in construction and infrastructure projects enhances soil stability by increasing water infiltration so there is a reduction of runoff (stormwater runoff and intense precipitation events are leading causes for erosion); increases vegetation growth; and provides a barrier between sediment and excess water so sedimentation is less likely to occur.  

• ➔ Expands the Soil Microbiome.

  The presence of organic matter in compost allows for growth of microorganisms, like fungi and bacteria, creating a really healthy soil environment. These microorganisms are responsible for breaking down the organic matter in compost piles, using their chemical make-ups to break down materials and absorbing other compounds. Adding these microscopic helpers to soil only improves soil health and further reduces the need for chemical fertilizers.

• ➔ Increases Carbon Sequestration.

  The circular process of composting is a vital tool for fighting climate change. First, separating food scraps and yard waste from entering landfill streams is extremely important because when either of these materials enter a landfill, or anaerobic environment, they release methane gas, which is a leading contributor to greenhouse gasses. Second, when compost is used as a soil amendment, the nutrient-rich organic matter encourages plant growth and therefore photosynthesis, a natural process that uses carbon dioxide and water to create food for plants. Plants pass carbon to the microbial community living in the soil where it remains until the soils are disturbed, causing the carbon to be released back into the atmosphere. Compost-soil mixtures have a great opportunity for being a carbon sink, or an area that is known to absorb carbon dioxide from the atmosphere, like the ocean!