How was the geography of crush in 400 bce important to its economy

Kush had a traditional economy, and the Nile River supported agriculture.

Explanation:

crop rotation kepy different plants in the soil instead of once constintly. when switching out plants you have different nutrients being absorbed at different speeds and different roots growing differently therfore the spoil and water flow have to adapt and carry fresh nutrients to carry the constant changes that were going on in the soil.