What is it?
Soil fertility is the soil's ability to provide a crop with the nutrients it needs. The fertility of the soil is determined by its chemical, physical and biological characteristics. Soil biota, such as worms, nematodes, fungi and bacteria, help to keep the soil fertile. The more varied the soil biota is, the better for the (fertility of the) soil. The soil's nutrient content and the amount of organic material it contains influence its quality as well. Organic material (humus) can absorb and retain water, making it easier for plants to obtain essential moisture. Organic material also serves as a mineral buffer, so that fertiliser isn't washed out as easily. Finally, soil biota relies on organic material as a source of food.
Soil fertility is an ecosystem service that the agricultural industry uses intensively every day. Soil fertility is important for good water regulation, disease and pest control, purification and the sequestration of carbon dioxide (CO2). The more fertile a soil is, the less tillage is required to get crops to grow. Fertile soil can therefore save time and money, while also providing good yields.
Human activities often interfere with soil fertility, making it necessary to invest effort and money to enhance or restore the soil's quality and productivity.
In real life
For the fertility of the soil to be maintained or improved, farmers, nature managers and public greenery managers need to adopt sustainable soil management strategies. For example, the addition of mineral fertilisers needs to be adapted to the local soil type, so as to ensure a good nutrient supply and the accumulation of organic material while looking after the soil biota. Soil biota also benefits from minimising the tillage of the soil. The use of green manure, such as clover, and crop rotation can help soil biota as well.