Hillslope Asymmetry work update (1)

In continuing my work with hillslope asymmetry, one of the most helpful things will be getting the erosion rates on the slopes. In order to determine the erosion rates for the slopes I’ll be employing the use of Cs-137 concentrations as described in my first post. At the study area in the college woods, we decided to pick ten sample locations along a straight hillslope transect.

Prior to sample collection, the hillslope was visited and traversed for the purpose of making observations. After walking along the entire slope (northwest and southeast facing sides) a transect for sample collections was chosen. Along this transect four sample locations were identified on each side of the slope as well as a location at the approximate crest. The locations along the transect were spread from bottom to top of the slopes and employed the naming scheme “North Facing (NF)” and “South Facing (SF)”. The final locations were named ‘Crest’, NF-1 through NF-4, and SF1 through SF-4 , with NF-4 and SF-4 being the locations closest to the base of the slopes.

Over the course of about a week and a half, samples were collected from these locations along the transect. At each location an organic layer sample was first collected using a 29cm x 25cm template giving the same area for each collection. This layer mostly consisted of materials such as leaves, twigs and acorns. This was followed by collecting an A horizon sample. This was done using a small auger that went about 15cm into the surface. The third sample we called the B-1 layer. A larger auger, starting where the A horizon sample ended dug further into the soil collecting another 15-20cm of soil. The last collection made we called the B-2 layer. A soil probe was inserted beginning where the B-1 layer ended, collecting additional soil of variable depths (~18-32cm). The collection of these four layers was repeated two more times for a total of three “runs” at each location. This was done in order to insure the reproduction of the results. Additionally at each location a pit was dug in order to retrieve a sample of what is called the Bt layer (very clay rich layer), generally deeper than 80cm. This gave a total of 13 samples from each sample location, or 117 in total. The hardest part in the sample collection was definitely digging a pit usually a bout a meter deep. The pit usually took an hour to 2 hours, having to take time to cut through thick roots and such. It was hard work battling mosquitos and many other insects throughout, but we were able to collect all the samples in the end.

Using small auger to collect A horizon.

Using small auger to collect A horizon.

Digging a pit to get teh Bt layer.

Digging a pit to get the Bt layer.


  1. kmholmes01 says:

    Hey Korede! It was cool reading about what you guys were doing for all that time out in the field. How did you define a clear boundary between each of the layers? It seems like some of the layers would blend together, especially the B-1 to B-2 divide. Given all the hard work you did, I hope the results pan out!