Ecologists Love Duct Tape

I spent the first week of June setting up my greenhouse experiment, and I have found it astoundingly easy to underestimate the amount of time that goes into a task.  It is one thing to know, intellectually, that you have just ordered 240 plant pots.  It is another thing entirely to spend three hours filling each pot with fertilizer and realize that you are nowhere close to being finished.  Before last week, I had an academic knowledge of the value of replication in biology.  More replication means more statistical power – how simple!  After constructing 60 pots for my experiment, filling them all with soil, fertilizing them, and transplanting seedlings into every single one, I have a greater appreciation of the work required to obtain that power.

I should back up.  There are two purposes to my greenhouse experiment: to determine whether milkweed plants actively forage for nutrients in the soil, and to quantify how they grow in different nutrient concentrations.  I needed to plant milkweed seedlings in the middle of a soil landscape with four distinct nutrient treatments (I descriptively named these treatments High, Medium, Low, and Zero).  To accomplish this, I had to construct a very specific kind of pot.  It needed to have four chambers with impermeable barriers that would prevent nutrients from leaching out of one chamber into another, but it also needed to have a central chamber from which a milkweed seedling would have access to all four nutrient treatments.  That construction took two days and two roles of duct tape, but the end result was elegant and simple.  I thought so, at least.

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(The pot construction process.  It wouldn’t have been possible without the help of Nikki, who is hiding out in the background of these pictures.  Thank you!)

After that, all of these pots needed to be filled with soil.  A lot of soil.  Each pot also needed to be fertilized with the appropriate mixture of ammonium nitrate, phosphorous, and potassium.  All of that took another two days, although I spent half of the first day driving to Richmond to get more soil (it really was a lot of soil).

Fertilizer2

(Each of those containers was filled with 4.5 liters of fertilizer.  They had to be refilled many, many times.  Again, this would not have come together without help: thank you Isabelle, Maddie, and Yahya!)

Finally, all of my pots were ready to hold a new seedling.  Transplanting 60 seedlings was actually the one part of this process that took less time than I expected.  After all of that, it was gratifying to see my little seedlings looking so handsome in their new homes.  They will grow there for two and a half months, although some will be harvested at different time points so that I can measure their root structures.  I am definitely satisfied with how this project has gone so far, and I am looking forward to digging around in the dirt some more in a couple of weeks.  I think that this could yield some really interesting results.

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(All of my cute little seedlings right after their transplant.  I marked pots with flags during the fertilizing process to avoid double-fertilizing.  The seedling on the right has a split stem, which is really unusual; milkweed normally has just one central stem.)

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