Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/29/1995
Publication Date: N/A
Technical Abstract: Tepetate is a hardened subsurface layer formed in soils with volcanic influence. The term tepetate is a local name for layers when they appear at the surface in Mexico. In Central Mexico, tepetate badlands are a significant source of sediment affecting offsite areas. Low productivity and land use pressure for these lands have led to efforts to reclaim or stabilize these areas. Reclamation disturbs tepetate and may increase erodibility. The objective of this study was to compare erodibility of natural and reclaimed tepetates to determine if conventional reclamation reduced runoff and sediment yield. A rainfall simulator was used to apply rainfall to natural and reclaimed plots at 6% slope. Plots of 1m x 7m and 1m**2 were studied to separate rill and interrill processes. Rill erodibility and critical shear were determined using added inflow. Natural tepetate produced runoff much faster and produced more runoff than the reclaimed plots. Interrill erosion was also greater for natural tepetate. However, reclaimed tepetate produced ten times more sediment at 85 mm hr**-1 intensity than at 57 mm hr**-1 indicating a threshold exists whereby the reclaimed tepetate may be more erodible than the natural. Rill erodibility was also very high (34.1 x 10**-3 s m**-1) indicating that care should be taken to prevent runoff. Reclamation of tepetate reduces the amount of runoff, but increases rill erodibility, therefore, the reclamation efforts should be used in conjunction with erosion control practices to further prevent runoff from occurring or slow it when it does occur.