Complex sentence: Zaï or Tassa are planting pits dug in the soil to catch water that were traditionally used in western Sahel (Burkina Faso, Niger, Mali) to restore degraded drylands and increase soil fertility.
Split into simpler sentences: Zaï or Tassa are traditional planting pits dug in the soil to catch water. They were traditionally used in western Sahel (Burkina Faso, Niger, Mali) to restore degraded drylands and increase soil fertility.