Getting Dirty and Getting Samples

My name is Mary and I am a high school intern with Water Rocks! this summer. I have always been interested in natural resources, and I will be pursuing a degree in Natural Resources and Environment Science with a concentration on Resource Conservation and Restoration Ecology at the University of Illinois Urbana-Champaign this fall.


I have had so many great opportunities and experiences with Water Rocks! this summer. I have been able to participate in multiple outreach events at county fairs and farmers markets across Iowa.  I have also had the opportunity to attend a farmer field day discussing everything anyone would want to know about cover crops.

Mary-ConservationStationMost recently I was able to go up to Nashua and collect water samples from lysimeters at the Northeast Research Farm. Our lysimeters are buried 24” deep and collect water from the surrounding soil.  The water samples are then tested to see the nitrate levels in the water at different times during the year and under different cover crop treatments. This research is very important in helping us better understand cover crops – they are one of the key practices in the Iowa Nutrient Reduction Strategy, where the goal is to try and reduce the nitrogen and phosphorus loads in Iowa waters by 45%.

The plots from which we collected water samples were each 6 rows wide – and we have plots that are in both corn and soybeans (rotated every other year). The entrance to the research farm is a couple of buildings, and then it moves straight into the research plots.  We had to drive a little ways to reach our lysimeter plots. There are many other research plots around our lysimeter plots. All of our fields were no till fields – some of them had cover crops in the spring (single species/mixtures) and some did not. We started collecting samples from the soybeans first, and then moved to the corn.

Lysimeters-InGroundCollecting water samples is quite simple, but finding the lysimeters when the crops are large isn’t always a piece of cake!  The lysimeters are buried underground, so all we can see is the PVC cap protecting it … and sometimes they get covered with soil or are hidden by residue.

Lysimeters-SuppliesOnce we have found the lysimeters, we grabbed our equipment which included a plastic beaker with a rubber stopper on top and a long thin tube attached, an air pump, plastic bottles to pour collected samples into, and a clipboard with labels to mark the samples.

Lysimeters-SamplingInProgressWe collected the sample by inserting the thin tube down into the lysimeter, attaching the beaker to the air pump, and applying vacuum to the lysimeter so the water would be sucked out.  After the sample was collected, we would have to apply vaccum to the lysimeter again (60 psi) so it could collect the next batch of samples.

Collecting clean samples is a key component.  If there was soil in the water sample, how would we know that the nitrates in the water weren’t from the soil?  I was out collecting samples the day after a big rainstorm, and of course it was really muddy out, so we had to be extra careful to keep the soil and mud off of the equipment used to collect the samples.  If we collected a dirty sample, then it would have to be filtered in the lab before the nitrate test could be done accurately.  Also, after every sample is collected, the plastic collection beaker must be rinsed out with DI Water (deionized water), so the next sample wouldn’t be contaminated by the previous sample.

Seeing the lysimeters and collecting water samples was very educational for me, and I was glad that I had an opportunity to see what research is being done and how it is done.  I learned how thorough you have to be when conducting research – there can be lots of variables in the field so quality control is really important.  I was also surprised by how dirty I was on the way home after collecting all of the samples!

So now we’ve collected water samples… next they go to the lab for nitrate testing. After that, there are lots of water quality data to analyze. Stay tuned to the blog as Emily, another high school intern, will tell us more about that process!

Mary-ShowingPigsBooneCoAs a fun side note, I wanted to share another one of my projects for this summer. In addition to this internship, I am a member of the Gilbert FFA Chapter and I recently showed pigs at the Boone County Fair (I’m number 344 in the blue shirt). That pig in the picture will be making an appearance at the Iowa State Fair – the show is on August 12th if you’d like to stop by and watch after you visit Farm Bureau Park and check out the Conservation Station!

Mary Marsh


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