The Effects of Solid Waste on Soil

Recycling

• By composting solid waste it can be recycled into a valuable soil amendment. When plants grow they extract nutrients from the soil. Many of the nutrients are concentrated in the seeds and leaves of the plants. These nutrients return to the soil for future use by other plants when they fall to the ground and decay. For plants that are specially grown as crops, the removal of the seeds, fruits and leaves takes nutrients from the soil. The majority of solid waste comes from the consumption of food. Nutrients are restored to the soil and can be used in growing nutritious crops by returning this waste to the soil.

Organic Matter

• The broken down components of plants and animals build up in the soil as organic matter. Solid waste is primarily organic matter, which has a large surface area for small amounts. The large surface area provides the ideal surface for elements essential to plant nutrition to attach to. Once these elements, including nitrogen, phosphorus and potassium, are held in the soil they are more accessible to plants. Adding composted solid waste to the soil will increase its fertility, structure, water holding capacity and increase the population of beneficial soil microorganisms.

Soil Fertility

• Soil waste contains many of the nutrients essential to plants. As solid waste is composted some of these nutrients will become more concentrated, while others, such as nitrogen, may be consumed by microorganisms aiding in the decomposition process. By adding organic matter to the soil, nutrients added to the soil by fertilizing will be held in the soil better, thus increasing its fertility. Without organic matter, fertilizer can easily be leached from the soil by water. Organic matter acts as a sink that holds nutrients in the soil for plants use.

Concerns

• Solid waste must be properly composted before it is applied to the soil. Applying raw sewage or insufficiently decomposed materials to the soil will not improve its fertility and can be a health hazard. Proper composting requires time and exposure to the air. Composting solid waste can be a complicated process depending on the amount. Small amounts of solid waste, if conditions are adequate, should be composted for six months to a year.