Researchers studied how rainfall and slope affect runoff on black soil slopes. They simulated rain to see how quickly water ran off and how much was produced. They found that higher rainfall intensity and steeper slopes led to more and faster runoff. The second rainfall caused more erosion than the first. Rills formed quicker on steeper slopes, and their size increased with slope steepness. Overall, the slope gradient had a bigger impact on sediment deposition than rainfall intensity. The study shows that on black soil slopes, higher slopes and heavier rain lead to more and faster runoff, affecting erosion and sediment movement.