Response of soil aggregate stability and rill erodibility to soil electric field

• The pathways of roots affecting soil electric field are analysed. • Different root parameters for predicting soil electric field are compared. • Effect of soil electric field on soil aggregate stability is elucidated. • Effect of soil electric field on rill erodibility is quantified. Soil electric field ( E 0 ) might have strong effects on rill erosion, and it is in turn largely affected by root growth. This study aimed to quantify the ability of roots to predict E 0 and elucidate the effects of E 0 on the mean weighted diameter of soil aggregates ( MWD ) and rill erodibility ( K r ). Samples were collected from three typical areas in the Loess Plateau of China, and each area had two typical grasslands. Soil detachment rates were measured using a hydraulic flume under five discharges (0.1, 0.2, 0.3, 0.4, and 0.6 L s −1 ) on a slope of 15°. The results indicated that plant roots negatively contributed to E 0 . The mean E 0 of grasslands (rooted soil) was lower by 3.27 times compared with that of fallow lands (root-free soil). With significant correlation ( P < 0.05), root length density ( RLD ) and root surface area density ( RSAD ) were found to be suitable parameters for predicting E 0 , which decreased exponentially with RLD (R 2 = 0.306) and RSAD (R 2 = 0.381). In addition, E 0 strongly affected MWD and K r by influencing soil repulsive forces. E 0 was negatively correlated to MWD (logarithmic function, R 2 = 0.96), but positively correlated to K r (linear function, R 2 = 0.88). Our results provide new insight into the mechanism of rill erosion considering plant roots.