The Beast

The LI-6400XT is a beast. A tamable one, thank goodness, but it takes time to tame. And each time I take this instrument from its foam cage and work with it, I find myself becoming more and more a LI-COR tamer.

My first introduction to the beast was in my first job out of undergrad at the USDA ARS unit in Raleigh. My colleague and I took weekly measurements on soybean plants, and I was given rudimentary training in operating the instrument. I could turn it on, hit the measuring button when the numbers seemed somewhat stable, and collect the data off of it at the end of the day. I had no idea what it was doing when I hit a button, what to look for to make sure it was measuring properly, or why "matching" was important. We had few issues, though, so my limited knowledge was adequate for the job.

Two years later when I learned my PhD project would be using the 6400, I arrogantly expressed my competence with the using the instrument. Of course I knew how to work it. I had done so for six months at my old job. It's a breeze. HA! I was a child. I knew nothing about the beast. I could put it together, yes. And I could turn it on, yes. But then I was lost at the very first screen. The programs had different names and I didn't know what made them different or how to choose the right one.

During my first field season, I learned through trial and error. Repeatedly. Painfully. Exhaustingly. I had to remeasure the same 100 plants eight times because my limited knowledge resulted in bad data 😳. Eight. Times. A six-day experiment turned into a thirty-day experiment. But I was learning. That fall, I attended the LI-COR photosynthesis training workshops and my eyes were opened. I finally knew what "matching" was and why it was important. I learned what the different programs were on the opening screen and how to adjust those to my project. I could add prompts and remove remarks and set stability settings. (We also learned about the domesticated breed of this instrument, the LI-6800. If the 6400 is a wild beast, the 6800 is a lamb. Gentle and simple and easy to use in every way imaginable. But I digress.) After this training, I at last had the tools and knowledge to master the LI-6400XT.

One and a half field seasons later and I can confidently remove and clean the fluorometer head mirrors to stabilize erratic CO2 values. I can rig a marine battery to power the instrument for 12+ continuous hours in the field. And I can take apart the console, remove broken battery ports, solder new ones in place, and put it all back to together in a way that still works correctly afterwards (miraculously). I know when and how to calibrate various sensors, what buttons to push to check for funky numbers, and how to troubleshoot when something looks wrong. Additionally, LI-COR support is on speed dial for all the questions that will inevitably arise I still don't know how to fix.

I'm learning how to be a LI-COR tamer. It's not an easy task, but good data is well-worth the investment. And as with any beast, "if you treat it right, it will treat you right" (Kusum Naithani, 2018).

Phase 1

May came crawling in, reluctantly, taking her precious time. Didn't she know that I've been waiting on her for a while now? May would mark the end of my first semester as a PhD student, the first semester of actually thinking (because I thought I was thinking before this semester, but I only now discovered the real definition of thinking, while reading), and the first semester as a Prep TA. Coming straight from my undergraduate, I had no clue what to expect, think, or do. Nonetheless, with the guidance from my mentor/advisor, it was a successful semester in my books, giving me a sense of great satisfaction at the end. 

Summer 2019 began like all others...with me being elated to take a break from the school year. After about a week of total relaxation, I continued working on myself, thinking up short and long term goals. My summer goals were to complete 3 papers, albeit this was a very ambitious and far reaching goal for a first year PhD student, who was still discovering where she fit best in this program. Nonetheless, I stuck to the goal, and dived into reading papers, or trying to. I dabbled with papers about photosynthetic processes, rice, crop modeling, and climate modeling. I soon rediscovered that there is so much I don't know. It got me thinking, "If I had a super power, I think it would be to touch any literature and absorb all the information." Unfortunately, I don't have that power. So I read on.

In addition to this, I signed up for two conferences, and aided my lab mate in experiments. We planted a lot of rice seeds! After a couple of weeks, we had very sad rice. They wanted to be outside, basking in the sunlight, but outside was not ready until the next week. When that week came around, we transplanted the rice plants, fertilized the field. The rice were soon happy again. In the third week of June, we planned to do measurements.

The weather app showed that it was supposed to be raining that week, but it was as if they had hired a new sun. This new sun did not come to play any games, it took it's job too seriously. It was hot! Scratch that... it was HOT. Skins were burning, shoes were on fire, and our vehicles had been replaced with furnaces. We came to the field at 5:30 in the morning, then began measurements at 6. We used our LI-6400XT and the MultispeQ devices, to obtain information which would inform us about the photosynthetic capabilities of the rice which we planted. MultispeQ takes measurements in 12 to 15 seconds, however using the Li-6400XT, meant that we would take about 3 hours to complete the measurements of the 80 rice plants...on a good day. We measured 3 times for the day, with a break at 10 AM, and at 1 PM. My lab mate and I laughed a lot, sang very loudly, danced a little bit, and learned about each other's cultures... all while doing science! It was fun, call it fun in the sun. 

On the 9th day of measurement, on the 1st of July, we ran into difficulties. We had a makeshift underwater battery, which lasted the whole day without changing (which was sweet because the batteries which came with the device lasts about 2 hours), connected to our LI-COR machine. We connected the battery via some make-shift wiring and high physics connections (real scientist business). On the 9th day, the pin, where the battery was connected to the Li-6400XT, broke off. It could not power on, until we could change the pins. We needed just one more day of measurement to have nine points to construct our temperature and light curves. We were able to obtain a LI-COR from another department, and after our minor set back, the first phase of measurements was over.