My professor wanted us to each conduct an experiment for class on something we thought would interesting. My experiment was very simple, but I'm not sure how to interpret my results. (Please note that this is not for homework – I'm just genuinely confused and trying to understand the data.)
Take soil samples, add varying concentrations of Roundup and water equalling a total of 50ml, seal in airtight jars, incubate for 7 days, run through a Gas Chromatograph, and record the rates of production for CO2, CH4, and N2O. Overall, there was the Control and then three treatments, for a total 8 jars because each had a duplicate:
- Control (Roundup: 0, H2O: 50ml),
- T1 (Roundup: 10ml, H2O: 40ml),
- T2 (Roundup: 25ml, H2O: 25ml),
- T3 (Roundup: 50ml, H2O: 0).
I expected the Control to have the highest levels of production, followed with a decrease in production for T1, followed by T2, and then T3, with T3 being the lowest because all microbial activity was inhibited by the massive dose of Roundup.
However, the results were a bit surprising.
- The Control rates were the highest, as expected.
- T1 showed a decrease in production, as expected
- T2, again, showed a decrease in production, as expected.
- And then T3 showed a significant increase in production.
Here are some graphs to illustrate this in more detail:
This is a new field of science for me, so forgive me if I'm missing something obvious, but my natural intuition is certainly not helping me out on this one. What are some possible causes for this increase – in particular for the N2O/denitrification? Or at the minimum, are there any particular resources I can take a look at to better understand why this happened?
This is my brain on paper, so forgive me again for any ridiculous things I say. But, could it have something to do with the denitrification process such that more gas is given off as N2O because the microbes responsible for processing the N2O into N2 have died. So in the previous Treatments 1 and 2, the N2O was lower because the N2O was being converted into N2 (but we never recorded the N2), but in the final treatment, no conversion occurred, so the N2O appears to go up, even through the microbes are functioning even less.