Discipline: Ecology Environmental and Earth Sciences
Subcategory: Plant Research
Jessica Brar - Heritage University
Co-Author(s): Ryan Christian, Richard Sharpe, and Amit Dhingra, Washington State University, Pullman, WA Corbin Schuster, Heritage University, Toppenish, WA
Biochar has recently drawn interest as a soil amendment, with many largely unsubstantiated and sometimes contradictory claims of its efficacy. Biochar is a form of activated charcoal that is created from organic material through pyrolysis: a process of thermal decomposition in the absence of oxygen. Current research indicates that, when used as a soil amendment, biochar can aid in water retention and nutrient binding capacity. Since biochar is largely recalcitrant, this additional porosity and holding capacity can potentially last for hundreds of years. This has led to claims that biochar can reduce the need for both fertilizer and water while increasing productivity and growth in crops. However, these claims are not rigorously tested, and biochar’s chemical properties may vary greatly depending on the feedstock used in pyrolysis and the concentration of biochar that is applied. This research seeks to create a controlled study to evaluate these claims and to provide more specific recommendations for the agricultural community. It also establishes methods that will be used to test additional biochar-soil compositions. In this experiment, ‘Oregon Spring’ tomatoes were subjected to six concentrations of biochar, ranging from zero percent to twenty-five percent in a base of SunShine mix #2 potting media. As the tomatoes grew in the greenhouse, high resolution images were recorded every 48 hours to track growth. The images were analyzed using ImageJ to quantify growth of each tomato plant. Growth rates were then compared across treatment types. Additionally, soil moisture probes measured water content of the different treatments every fifteen minutes. Upon conclusion of this study, eighteen plants were removed to collect biomass data. During the early stages of growth, the tomatoes that were treated with biochar experienced significant stunting. Within twenty-seven days, both the 1% biochar and 2.5% biochar treatment plants demonstrated an accelerated growth rate surpassing the rate of growth of control plants while the remaining plants were stunted. The soil moisture data showed that treatments with higher concentrations of biochar had higher volumetric water content and the rate of water loss was slower compared to soil with lower biochar concentrations. Biomass data exhibited similar trends of decreasing mass with increasing biochar concentration. The results obtained so far indicate that there is a need to evaluate lower concentrations of biochar. The concentrations tested may indicate presence of toxic byproducts or fertilizer burn. While the addition of biochar may have increased water retention of the soil, the results seen are more likely due to the variation in plant size. Evaluation with lower biochar concentrations and additional genotype of tomato needs to be done to evaluate the effects of biochar on plant growth.
Funder Acknowledgement(s): Jessica Brar was supported by the National Science Foundation with a Heritage University REU grant, project number DBI 1460733. This research was supported by ARC Hatch funds to Amit Dhingra.
Faculty Advisor: Amit Dhingra, firstname.lastname@example.org
Role: I executed the experiment, monitored the treatments, collected all data, and analyzed all data. The methods of the experiment were set forth by my mentor, but we all worked as a team to decide the best ways to monitor and collect data as the trial proceeded.