Happy World Soil Day!
Today we celebrate the significance of soil and the importance of taking good care of it (UN). Over 99% of our food comes from the soil, with the other 1% coming from the ocean. In observance of this important day, we will share six points about soil and some resources to help increase your understanding about soil health and management.
- Soil is a living ecosystem composed of minerals, water, air, and organic matter. In fact, soil is extremely biodiverse with dense networks of microorganisms, fungi, insects, and macrofauna. 25% of the world’s biodiversity is found in soil.
- Composting can improve soil health. Adding organic matter to soil improves soil structure by increasing soil porosity and decreasing compaction, while still acting as a binding agent to create soil clumps. This makes a more stable soil structure that is better able to retain water and hold more soil nutrients.
- Plant roots help improve the soil. The process of photosynthesis allows plants to cycle carbon back to the soil. This creates an optimal environment for microscopic organisms to live around the soil roots, in an area called the rhizosphere. Roots decompose adding organic matter and till the soil as they grow. Some plants are better than others at giving back to the soil and are able to fix nitrogen, which means they can remove nitrogen from the atmosphere and add nitrogen to the soil. Legumes, such as beans, peas, and lentils, are a good example of this. Legume plants and rhizobia bacteria in root nodules can form symbiotic relationships, which convert atmospheric N2 into ammonia NH3, which is bioavailable to plants.
- Soils impact the water cycle. Healthy soils are able to absorb water, hold it, and release it to plants and organisms to support their growth and development. The microorganisms in soil can also help filter water by breaking down harmful pollutants. Conversely, unhealthy soils have reduced water infiltration and increased soil erosion, a process where soil particles are carried with water along the surface of the soil. The eroded soil can be carried into waterways and increase water turbidity, along with the presence of excess organic matter, nutrients, and waste products. Overall, this reduces the health of the waterway.
- Healthy soils hold more nutrients, which are needed for healthy plant growth. These nutrients are converted to healthy, productive plants with higher yield. Plants obtain carbon (C), hydrogen (H), and oxygen (O) from the air and water through photosynthesis. All other nutrients contained in fruits, vegetables, and grains come from the soil.
- Fertilizers can replenish nutrients to the soil. Most commonly used fertilizers add nitrogen (N), phosphorus (P), and potassium (K) to the soil in bioavailable forms. These nutrients are needed to grow healthy and productive crops. These nutrients are needed to grow healthy and productive crops and fertilizers can help maintain or increase yield, even if soils are depleted.Growing productive crops can help add organic matter to the soil through roots and incorporating crop residues. During the growing season a healthy established crop prevents erosion and protects the soil surface. The Haber-Bosch process which is used to create nitrogen fertilizer from nitrogen in the air is estimated to be the reason half of the world population is alive today (graph).
