Current Projects
Soil Carbon and Greenhouse Gas Dynamics in a Vegetable Production System
As a member of the Sihi Lab, I have had the opportunity to lead a project to implement an autochamber system on a working organic farm to better understand real-time impacts of land use decisions on greenhouse gas emissions. We have been fortunate to collaborate with Daniel Parson, manager of the Oxford Organic Farm, to locate a mobile lab on site and coordinate soil sampling campaigns through the growing season. The lab consists of a Picarro G2508 and a custom multiplexer designed with help from the Emory Physics Machine Shop to allow the automated closing of 16 "auto-chambers". These chambers allow a sealed gas flux measurement of each plot once every 4 hours. Custom R scripts are then used to merge datasets, trim to times of importance, and fit flux curves. These instruments are run 24/7 to build a high resolution picture of gas flux dynamics throughout the growing season. Individual soil moisture and temperature probes are buried alongside each chamber to help understand how rainfall and irrigation events trigger fluxes of interest. We aim to use our targeted soil sampling campaigns to track how amendments change microbial biomass, community diversity, carbon use efficiency, and nitrogen speciation throughout the season. For this year, the cash crop of interest was okra. We implemented three amendment treatments (control, compost, biochar+compost) and two incorporation strategies (shallow tillage, deep tillage) that are readily available to an organic land manager. Results will be used to guide future experimentation and management decisions on the farm.
Dr. Debjani Sihi, Dr. Biswanath Dari, and Milon Barmon have been co-leads on this project, helping with experimental design, labor, and troubleshooting as we deployed this system for the first time in Spring of 2023.
Dr. Debjani Sihi, Dr. Biswanath Dari, and Milon Barmon have been co-leads on this project, helping with experimental design, labor, and troubleshooting as we deployed this system for the first time in Spring of 2023.
Multiplexer Construction for the Terrestrial-Aquatic Interface Project
As a collaborator on a DOE-funded project led by Dr. Alex Cory, I have built a multiplexer system to extend the capabilities of the Sihi Lab Picarro G2508. This instrument allows the programmed measurement of up to 32 sample cores for CO2, N2O, CH4, and NH3 gas fluxes. I followed the schematics as outlined by Berry et al., 2021 to create this set-up for our lab. Using a relatively inexpensive software (CommOperator), we are able to drive our relay board according to a custom script and and record relay status for use in later data merger with the recorded Picarro signal. This allows the switching of flow lines to samples (cores, jars, or even chambers) and the closed-circuit measurement over desired time windows. Similar to the multiplexer deployed at Oxford Farm, this approach allows flux estimates when paired with a custom R script I devised for use with the system.
Currently, the multiplexer is being used to measure fluxes of samples from the COMPASS project before, during, and after simulated flooding events. Dr. Alex Cory has created a column design using a modified optode approach to measure spatial distributions of O2 concentrations following disturbances. The project aims to pair these spatial datasets with porewater samples and flux estimates to build better predictive models to capture what happens at the terrestrial-aquatic interace.
Building this setup was a great learning experience for me and something that I hope will be useful for future environmental scientists in the Sihi Lab. It took ~4 weeks to complete and another week to test and validate function. I spent countless hours soldering and even more refining the communication link between the relay drivers and our lab PC. I'd like to especially thank Lowel Ramsey (Emory Physics - Electronic Coordinator) for building my confidence in multiplexer creation and encouraging me to take on and complete the project.
Currently, the multiplexer is being used to measure fluxes of samples from the COMPASS project before, during, and after simulated flooding events. Dr. Alex Cory has created a column design using a modified optode approach to measure spatial distributions of O2 concentrations following disturbances. The project aims to pair these spatial datasets with porewater samples and flux estimates to build better predictive models to capture what happens at the terrestrial-aquatic interace.
Building this setup was a great learning experience for me and something that I hope will be useful for future environmental scientists in the Sihi Lab. It took ~4 weeks to complete and another week to test and validate function. I spent countless hours soldering and even more refining the communication link between the relay drivers and our lab PC. I'd like to especially thank Lowel Ramsey (Emory Physics - Electronic Coordinator) for building my confidence in multiplexer creation and encouraging me to take on and complete the project.
Sihi Lab Infrastructure
Another part of my responsibilities as a Research Scientist has been building out the infrastructure and analytical capacity of the Sihi Lab at Emory University. This has included the purchasing of essential instrumentation to operate a lab centered around soil health as well as set-up, maintenance, and training of students on proper instrument operation. Instrumentation has included an FlashSmart Elemental Analyzer (CE Elantech - NC Soil Argon), Shimadzu TOC-L, Spex Mill/Grinder, Qsonix Sonicator, Tecan Infinite 200 Plate Reader, Lindbergh Muffle Furnace, Sorvall Legend Centrifuge, Precision Incubators, and a Shel Lab Drying Oven. Beyond building the physical infrastructure of the lab, I have led efforts to standardize data processing using open source software (RStudio) and reproducible project folders and processing templates. This approach maintains raw datasets and allows all future users to reproduce analytical processing steps with transparency.