EFFECT OF MULCHING ON SURFACE RUNOFF UNDER NATURAL PRECIPITATION OF MOSUL CITY

The study was conducted to determine the effect of mulching on surface runoff under natural precipitation of Mosul city (Northern of Iraq). Standard flumes (100 x 30 x 12 cm) were filled with soil and treated with four types of mulching (weeded soil, weeded soil control, wheat straw and gravels). The flumes were exposed to the natural precipitation of 2004 2005 season. The result revealed that all rainstorms gave a significant amount of surface runoff depth and the treatments were ranked in the following order: weeds control soil > weeded soil > gravel mulched soil > wheat straw soil. Runoff threshold values were determined graphically and showed some variation Among the treatments. The calculated runoff efficiency of the studied treatments showed that wheat straw gave the lower value while the weeded soil control offered the highest value of runoff efficiency.