What is the main benefit of adding compost to soils?

The main benefit of adding compost to soils is that it enhances soil structure and nutrient retention. Compost is a rich source of organic matter, which plays a critical role in improving the physical, chemical, and biological properties of the soil. By incorporating compost, the soil’s structure is improved, leading to better aeration and root development.

Furthermore, compost increases the soil's nutrient-holding capacity, allowing it to retain essential nutrients more effectively. This is particularly beneficial because it can reduce the need for chemical fertilizers, promoting a more sustainable agricultural practice. The organic matter in compost also acts as a food source for beneficial microbes, contributing to a healthy soil ecosystem.

The other options do not reflect the true benefits of using compost. Adding compost does not increase the need for chemical fertilizers; rather, it can reduce reliance on them. Compost is known to support microbial activity rather than prevent it, as healthy microbial life is essential for nutrient cycling in the soil. Additionally, compost generally increases, rather than decreases, water retention by improving soil structure, allowing it to hold moisture more efficiently.