KBS research associate Neville Millar and intern Karma Hassell spent the day pounding plastic buckets into the ground. They intend to use these to measure greenhouse gas emissions from the soil. There are no wires, no gauges, no tubes. Just a plastic bucket and a syringe to take a gas sample.

Four times an hour, Millar and Hassell will take their samples to check levels of not only the well-known greenhouse gas carbon dioxide, but also it’s more potent counterpart, nitrous oxide. According to Millar, one nitrous oxide molecule is equivalent to 300 of carbon dioxide, therefore if you can prevent one ton of nitrous oxide from being emitted into the air, it’s the same as stopping 300 tons of carbon dioxide, or roughly the equivalent of driving an average size car around the Earth almost 30 times.

Nitrous oxide is most commonly emitted from agricultural practices, such as nitrogen fertilizer and manure applications. Millar’s study looks at several plots of soybean crops, some of which were fertilized in previous years when corn and winter wheat were growing and others that have never been fertilized. The object of the study this year is to determine if leftover nitrogen residues from fertilizer still contribute to nitrous oxide emissions into the atmosphere, even after application has ceased.

Beside the plastic buckets encircling one or two soybean plants are metal boxes complete with a handful of colorful wires sprouting from the cages. Millar calls this contraption the high-tech version whereas the buckets are called low-tech, yet both mechanisms essentially do the same thing. The boxes are fully sealed with the gases emitted from the soil being sucked through the tubing into a nearby trailer where the samples are collected and analyzed and the data is stored. The buckets, or “chambers”, are considered low-tech since they require humans to extract the samples.

This specific study has been ongoing since 2007. The overall aim of the work is to look at the tradeoffs between varying nitrogen fertilizer rates, crop yields and nitrous oxide emissions to help determine the amounts of fertilizer which are needed to achieve an environmental and economic balance.

Excess nitrogen fertilizer use has long been criticized but due to its low cost little has been done to significantly curb its use. The results of the experiment will be important for promoting reduced fertilizer use in the Midwest, the ‘bread basket’ of the US.