Intercropping maize and soybean can boost crop productivity and water efficiency. A study looked at how planting dates affect water uptake in these systems. They found that planting maize and soybean at the same time led to deeper water absorption by maize. Delaying soybean planting didn't change its water uptake depth, but delaying maize planting made its roots shallower later on. The best planting time for intercropping on the Loess Plateau was when soybean was sowed 4 weeks after maize. This timing had the highest impact on yield and water use efficiency.