Interrill and rill erosion as affected by plot configuration on a sandy loam Hapludalf soil

Abstract

The objective of this study was to compare rill and interrill erodibility and critical shear stress, for two configurations of soil surface: rectangular (RCS) and triangular (TCS) cross-sections. The experiment was done in 1998 on a conventionally tilled Hapludalf with a sandy loam soil surface texture. The interrill plot dimensions were 0.50 by 0.75 m, while for rill, the dimensions were 0.20 by 5.90 m for RCS, and 0.50 by 5.90 m for TCS. Constant simulated rain of 65 mm h^-1 was applied on the interrill plots for 90 minutes, whereas for the rills, besides rain to prewet the soil, five extra inflows of 0.0002 m³ s^-1 up to 0.0010 m³ s^-1 were applied. The interrill detachment rate Di (2.09x10^-4 kg m^-2 s^-1 for RCS and 3.35x10^-4 kg m^-2 s^-1 for TCS), interrill erodibility Ki (1.77x10⁶ kg s m^-4 for RCS and 2.00x10⁶ kg s m^-4 for TCS), rill erodibility Kr (0.0110 kg N^-1 s^-1 for RCS e 0.0074 kg N^-1 s^-1 for TCS), and critical shear stress tc (2.61 N m^-2 for RCS e 2.00 N m^-2 for TCS) were not statistically different for the two cross-sections, and can be determined on any of the plot configuration for sandy loam soils.