Learning by doing

Amidst the daily chaos of running a research farm, one industrious intern—with help from his mentors—finds time for his own experiment.

By Bart Renner

Interns come to Rodale very curious about a lot of things. Since most of us have already been through at least four years of college, some of life’s major curiosities have been checked off the list and we’re ready to focus on the burning questions of science. We want to know what it’s like to work at the “cutting edge” of organic farming research. With my experiences at Ball State University and a few research summers with the U.S. Forest Service, I knew that research in any field involves a lot of tedious work and attention to detail before you finally get those precious numbers known as results. I joined the Rodale Institute excited to get back into the research world and, if possible, get my hands on my own little experiment. After talking with Richard Bernard at Seeds of Change, and with my supervisor Paul Hepperly, Ph.D., I was given the chance to measure the emergence of seven sweet corn varieties that Richard was testing for next year’s catalog. Half of the seeds were covered with a standard anti-microbial treatment and the other half was left untreated. Our experiment would be designed to test all these seeds in both conventionally and organically farmed soils from the Farming Systems Trial (also known as FST, a long-term trial that compares the productivity of organic and conventional farming systems) at Rodale. It was a great chance for Seeds of Change to test sweet corn varieties and for Rodale to compare its conventional and organically farmed soils.

So, before I knew it I had a big pile of corn seed bags sitting on my desk (alongside another pile of bags of dead moths I had been collecting for the cutworm moth experiment we’re doing… it’s not weird, its entomology). I talked with Dr. Hepperly and Matt Ryan (research agroecologist at Rodale) about the best way to set up the experiment. I then transferred what was in our brains into written protocols, diagrams and Excel spreadsheets--the way all good scientists need to see things in order for it to make sense (even if it only makes sense to the scientist who made it). The experiment was a standard complete block random design with four replications.

To compare emergence we used both the organically and conventionally farmed soils from FST, expecting this would simulate natural soil conditions for the seed in organic and non-organic circumstances. After planting and carefully labeling the seeds, they were subjected to the Standard Iowa Cold Germination Test, slightly modified to control for the treated and untreated seeds. The idea behind this test is to place the freshly planted and well-watered seed trays at 50°F (the temperature where corn germination shuts down) for a week, which creates a soil environment ideal for fungal growth (similar to cold spring conditions when most farmers like to plant) and rigorously tests the vigor of the seed.

We had several hypotheses about what would happen in this test. Seeds of Change was obviously interested in which of its seed varieties would do best, so I did a regular germination test in the lab (sterile lab conditions, ideal for the seed, only looking to see if a root sprouts from the seed) and found that most varieties did well with a few exceptions. What was really interesting is that the treated seeds did worse than the untreated seeds in a few cases. As far as our soil comparison, longtime Rodale Institute gardener/groundskeeper April Johnson told me she thought the organic soils would fare better since they are not as compact, are spongier, and allow for better drainage, which is critical when looking at damping off and soil fungus.

Both seed rot and seedling disease can cause poor stands of sweet corn. In cold soils, the seeds decay and the seedlings may die before they reach the soil surface. In warmer soils, it is more typical that you will have emergence, but then have rotten roots and stems at the soil line. Cool, wet soils typically slow seed germination and the development of young seedlings, so seeds and seedlings are exposed to fungi for a longer period of time. Additionally, low quality seed often produces seedlings that are weak and survive poorly in cold wet soils. Pythium spp., Macrophomina phaseolina, Gibberella zeae, Penicilllium oxalicum and others are typical fungi that may infect the seeds and seedlings. To avoid these fungi, sweet corn should be planted after the soil temperature climbs above 55°F.

After a week of 50°F torture, I took the trays to plant-germination heaven: a Rodale Institute greenhouse. I watered them every day, making sure they stayed moist and all got the same amount of water. After about 10 days in the greenhouse, I counted the number of seeds that had emerged. I treated all emergence the same, whether the plant was already 3-inches tall or was just barely poking through the soil.

During the next month, thanks to Dave Wilson (research agronomist at Rodale) and Matt Ryan, I slowly learned all the things I should have learned in college about analyzing data with Microsoft Excel. Rita Seidel (lead FST researcher at Rodale) also felt my pain and showed me some shortcuts to get the statistical analysis done in about 1/100th the time it would have taken me. I was so proud of how small my p-values were.

So what happened? The organic soil had more than 100 percent better emergence than the conventional soil. Soil organic matter, commonly higher in organic systems, may be a big contributor to this phenomenon, since organic matter not only holds moisture in the soil but also helps to drain the excess more effectively, creating a more balanced environment that gives the seed enough moisture for germination, but not enough to cause an infestation of fungus that might prevent emergence.

The anti-microbial seed treatment had no significant effect on seed germination and resulting emergence. There was a great deal of difference in how each seed variety fared in the harsh soil climates, with the ‘Sweet Ice’ variety, among others, doing quite well in some cases.

What does this mean? Well, first of all, this study needs to be done a few more times to see if we get these results again. If we do, this study lends further credence to the fact that we need to focus on building and improving our soil, not on costly chemical inputs. We also need to continue to investigate and promote vigorous new seed varieties that are adapted to the local soil conditions (instead of just trying to kill the soil conditions).

Intern time seems to be a very precious and limited resource for all my supervisors who already have a fantastic amount of work they are trying to cram into the only growing season we’ll see this year. Dave Wilson is usually only half joking when he talks about just setting up camp and staying there in his little cubicle (I personally think the only thing stopping him is that the tent wouldn’t fit). I owe all my supervisors—Matt, Dave, Rita and Paul, and Richard Bernard from Seeds of Change—a big thanks for letting me take on this project when we already had plenty. It’s been one of many great learning experiences here at the Rodale Institute.