Hy was the basin system of irrigation largely abandoned by farmers near the nile river in modern times?

Because it only support the planting of one main crop, meanwhile perennial system allow the planting of multiple crops

The basin system can only supported one type of crops because it really depended on nile river's annual flooding, which make it far Less effective than the Perennial system. So many people in modern times started to switch to Perennial system

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