Here's why:

* Rich in organic matter: Chernozem soil is formed from the decomposition of grasses, which contribute a high amount of organic matter. This makes the soil very fertile, capable of supporting abundant plant growth.

* Deep and thick: These soils have a thick, dark-colored topsoil layer, often extending several feet deep. This deep layer provides ample space for roots to grow and access nutrients.

* High in nutrients: Chernozem soil is rich in nutrients like nitrogen, phosphorus, and potassium, which are essential for plant growth. This high nutrient content contributes to its exceptional fertility.

The chernozem soils of the steppes are considered some of the most fertile in the world, making them ideal for agriculture.