The St Edward’s campus is well known for its natural beauty and ancient trees. surely though, there are certain areas that one would expect to be healthier than others, after all the property line does extend all the way to South Congress Avenue, one of the busiest streets in the city. For my project instead of returning to sites for observation, I took the campus with me to conduct my own experiments at home. First I located two drastically different locations on campus to collect my soil samples, the first spot which, for the remainder of this blog I will refer to as site “A”, was inside the Forrest on the hill behind Theresa. The second location, “B”, was around the pond immediately adjacent to S Congress Ave. the final location “C” was taken by the ground about a 5 minute walk south from campus.
Sample A was essentially devoid of any rocks or plant matter, it had a moist texture and was a very rich brown in color. Sample B was almost the opposite, apart from being more grey than brown, it was very rocky and noticeably drier than A and was also filled with dead plant leaves and stems. Sample C seemed to be somewhat of a mix between the two, it was somewhat rocky but not nearly to the extent of sample B, and also had significantly less recently deceased plant matter. samples B and C fit very closely to the general description for the soils types found in the Edward’s plateau, being described as mostly shallow, stony, or gravelly (Soils of Texas). when hypothesizing what might be expected to happen there are a number of factors to consider. on the one hand, the soil taken from the top of the hill may have less contaminants but on the other hand it was a much higher elevation and not near a body of water like the second site which was also much lower in elevation so in theory it would receive more nutrients and minerals flowing into it from higher locations.
I decided to track the growth of two different herbs in each three of the soil samples to try and get a concrete idea of which areas might have healthier soil. The top row of seeds planted were parsley and the bottom was oregano. both of these herbs grow fairly well almost anywhere and grow somewhat quickly making them a feasible choice to examine over a period of few weeks. each pot was then marked either Parsley or Oregano followed by either A, B, or C depending on the soil sample. the system being used ensures all pots are receiving about the same light energy and water which other than available space, are the biggest determinants of the size a plant can grow. Every day the plants receive at least 14 hours of light and their growth progress is also checked daily. Here is an abridged timeline of the main events that happened after the seeds were planted:
September 19: seeds planted.
September 24: Oregano B sprouts first with A and C following shortly after. unidentified grass began growing in Parsley B.
September 28: Parsley first sprouts in A and C.
October 1: Oregano in all pots continue growing, no clear leader at this point.
October 3: Parsley sprouts in B.
October 5: Oregano branching begins in all pots, number of sprouts higher in B and A.
October 7: Parsley in C begins branching.
October 10: Parsley in A begins branching.
At this point over three weeks in, I’m beginning to notice something strange. While the parsley in C is objectively growing the fastest, this soil type has not been so great for the oregano, and the exact opposite is true with sample A. speaking of which, in Parsley A the only seed to successfully germinate has actually began growing towards the parsley in pot B, meanwhile samples A and B are leading in terms of Oregano growth. I think at this point it will be interesting to see the effects on the plants as they begin to enter their more intense vegetative state where they will be growing rapidly until they reach the flowering stage and produce seeds. In the next three weeks i expect to see much more plant growth, especially in the pots that are the furthest along in their development. considering Parsley A and C sprouted a full 5 days prior to the seeds in parsley B, it is possible the plants might begin growing further into the parsley B area, limiting B’s ability to grow.
Day 1 vs Day 22
[top row left to right: Parsley A, B and C. Bottom row left to right: Oregano A, B and C.]
“Soils of Texas.” Texas Almanac, Texas State Historical Association, texasalmanac.com/topics/environment/soils-texas.