GROWING CORN ROOT EFFECTS ON INTERRILL SOIL-EROSION

The relationship between Plant roots and interrill soil erosion is imp ortant in dynamic soil erosion predictions. Rainstorm simulations of s imilar intensity (63.5 mm h-1) were conducted in the summer of 1989 on 1 by 1 m field plots of Cecil sandy loam (clayey, kaolinitic, thermic Typic Kanhapludult) to study the effect of different root length dens ities, L(v) (cm cm-3), of corn (Zea mays L.), during vegetative, prean thesis, and anthesis plant developmental stages on interrill soil eros ion. Sediment loss and runoff data were assigned to treatments, L(va), on the basis of L(v) range to reduce rooting variability associated w ith plant developmental stage. To avoid confounding by canopy cover, c orn plants were cut at the stem base and removed for the first four se ts of simulations. A reference set of simulations was performed on a f allow plot containing no roots, L(va0). Runoff and detached sediment w ere collected in buckets from each plot during successive 5-min interv als over a 1-h period. Thirty cores, 5 cm in diam. and 5 cm deep, were taken from each 1-m2 plot and roots were washed from the cores and me asured. Means for runoff and detached sediment were generally not sign ificantly different for the high L, or L(va), and L(va0). When L(va) w as < 1.5 cm cm-3, runoff and detached sediment were significantly lowe r during the first 30 min of simulated rainfall. High densities of liv e corn roots did not reduce interrill soil erosion from a moldboard-pl owed Cecil sandy loam.