Q&A for How to Conserve Soil

Mulching, contour barriers, terrace farming, rock dam, intercropping, contour plowing, shelter belts.

Earthworms decompose dead organic matter to add nutrients to dry soil. They create a very organic and nutrient-rich material called humus. This helps in soil conservation efforts by essentially reviving soil with less nutrients.

Irrigation itself isn't directly related to soil conservation, as it deals with supplying water to growing plants in places where natural water sources are inaccessible, but the practice of irrigation will keep plants healthy and firmly rooted, which helps hold the soil in place. It is essentially performed in reverse for runoff control methods like digging drainage ditches.

All food that we eat ultimately comes from plants, and all plants need soil to survive. Even when you eat meat, you're either eating an animal that fed on plants to survive, or an animal that fed on animals who fed on plants to survive. Ultimately, all energy in food comes from the sun. Other than microscopic creatures, plants are the only living being capable of turning that energy into food. At some point, everything you eat got its energy from plants. Without plants, life on Earth couldn't exist. And without soil, plants wouldn't exist.

Trees, like all plants, hold soil together with their roots. For instance, the Dust Bowl was a natural disaster that happened when farmers broke up sod (dry soil packed together with small grass roots) and tore all the roots out of the soil. Without the grass roots to hold the soil together, it simply blew away. Tree roots function the same way as those grass roots did, just on a larger scale (because tree roots are bigger). When trees are cut down, their roots decompose and stop holding the soil together, and so the soil erodes.

When soil is exposed by events like heavy rain, agricultural practices, erosion, etc., it can be blown away by the wind or swept away by rain, flood or other water. This means that the exposed area has lost its soil. Such soil often ends up many miles away from its original place.

Their roots can help hold the topsoil in place and stop the soil from being blown away. This works best when the roots are close enough together to collectively cover a large, unbroken area. Also, trees and shrubs close together can benefit from and provide benefits to the micro-biota thriving in the soil.