Erosion control

One of the easiest visual response by including cover crop and having plants growing throughout the growing season is erosion control. By having living roots in the soil, the chance of having a major rain or wind storm taking top soil away is minimized. Increasing organic matter helps hold the soil aggregates together, allowing more roots in the soil profile, and faster water infiltration. By maintaining soil armour, the soil is protected from the elements and will allow plants to continue growing under climatic disturbances.
Soil armour is having some cover on the soil. It can be living plants or residue from past crops or cover crops. Soil armour is protection for the soil from the elements. When the soil is covered, there is less risk to having wind blow over it and drying it out, potentially forcing the plants and the soil biology into dormancy or worse, killing them. From the stand point of water erosion, having the old root pores in the soil will allow water to infiltrate quicker. Standing residue will slow down water flow which will reduce the amount of residue and soil the water can carry away.
Erosion is regarded as one of the unnoticed losses in agricultural production systems in North America. It is amazing how the tonnes of soil, residue, organisms, and nutrients are lost per acre per year with our current management systems. Some estimates in Iowa show between 1.2 and 4.8 tonnes per acre per year of soil lost. Needless to say, it is quicker to lose it than to replace it. Most see soil erosion as just losing soil. The loss is actually organic matter, fine soil particles, soil microbes, humus, and nutrients. Never mind the loss of potential future productivity.