GROWING CORN ROOT EFFECTS ON INTERRILL SOIL-EROSION

The relationship between Plant roots and interrill soil erosion is important in dynamic soil erosion predictions. Rainstorm simulations of similar 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 densities, L(v) (cm cm-3), of corn (Zea mays L.), during vegetative, preanthesis, and anthesis plant developmental stages on interrill soil erosion. Sediment loss and runoff data were assigned to treatments, L(va), on the basis of L(v) range to reduce rooting variability associated with plant developmental stage. To avoid confounding by canopy cover, corn plants were cut at the stem base and removed for the first four sets of simulations. A reference set of simulations was performed on a fallow plot containing no roots, L(va0). Runoff and detached sediment were collected in buckets from each plot during successive 5-min intervals 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 measured. Means for runoff and detached sediment were generally not significantly different for the high L, or L(va), and L(va0). When L(va) was < 1.5 cm cm-3, runoff and detached sediment were significantly lower during the first 30 min of simulated rainfall. High densities of live corn roots did not reduce interrill soil erosion from a moldboard-plowed Cecil sandy loam.