Dateline East Arkansas: Ag Engineer Works Alongside Energy Department to Ensure Quality and Consistency
Benjamin Runkle and his research team are seeking ways to reduce water consumption and carbon emissions in rice fields to make rice production more environmentally sound and economically efficient. Runkle, an assistant professor of biological and agricultural engineering, is working in eastern Arkansas this summer, setting up and monitoring instruments to measure water, soil and water chemistry and methane levels in rice fields. This is the third in a series of his research dispatches from the field.
Last week’s field visit contained an extra degree of best scientific practice. Our measurement system that gathers data on carbon dioxide and methane emissions from the rice field to the atmosphere is a complex and expensive version of a meteorological station. There are more than 600 of these measurement systems in operation around the world. To ensure comparability and high-quality data collection across these sites, the Department of Energy has established the AmeriFlux Network (ameriflux.lbl.gov). This network encourages connections among different sites, collects and archives data, and performs quality control measures. Last Thursday, the AmeriFlux Technical Team arrived at our site to provide a site assessment. They have a portable measurement system that they move around the country each summer to help all these sites stay on the same page. Their QA/QC scientist, Stephen Chan, arrived to the site on Thursday with a tower to install and advice to give.
Stephen’s instrument tower is about 20 feet from ours and provides a comparison dataset for the length of his 10-day visit. This tower has near-identical instrumentation to ours and also has some new devices so he can assess whether changing from one instrument type to another requires calibration. The portability of these instruments is an asset. They can be configured to draw low amounts of power, such that a bank of solar panels or a small diesel generator is sufficient to charge them. Other groups have even put the instruments on a truck to move it between several field sites, which is helpful in determining whether the field chosen is representative of regional growing conditions.
In addition to providing a comparison dataset, Stephen’s visit also allows us the opportunity to discuss different configurations of equipment. Our micrometeorological instruments need to be close together – to measure the same parcels of air – but also far enough apart to avoid disturbing each other. Our solar radiation sensors should be south of the tower so the tower does not shade the sensors. The data should be logged at appropriate and synchronized time points. Stephen has helped guide us towards better sensor placement, has approved our data logging strategy, and discussed ways to improve our site. We’re more and more confident that our data will be well-received by the research community when it gets released.