Why soil looses its fertility?

Answer 1

Every plant extracts carbon, nitrogen and trace elements from the soil. After a few years, the soil doesn't have many nutrients left in the soil.

Farmers replace the nutrients in the soil with fertilizer, or by rotating their crops to plant something different each year. For example, farmers will plant a crop of clover every few years, and the clover extracts nitrogen from the atmosphere. When the farmer plows the clover back into the soil, the nitrogen remains in the soil. Every few years, the farmer may plant hay or grass, and allow cattle to graze on the grass. The cattle manure is left in the fields, and plowed under the next year; this also restores the missing minerals and nutrients.

One very popular natural fertilizer was "guano", or bird manure. Over centuries of time, birds nesting on certain islands would leave - literally! - MOUNTAINS of manure, and this could be mined and shipped to farmers as fertilizer.

Since the early 1900s, chemists have created artificial fertilizers, which are less expensive and less dangerous.

Answer 2

Soil can lose its fertility due to a variety of reasons, including overuse of chemical fertilizers, erosion of topsoil, depletion of nutrients through farming practices, and lack of proper crop rotation. These factors can degrade the soil structure and decrease its ability to support healthy plant growth.