Underground pipelines have been dubbed the safest means of transporting liquid energy, and they span all across the United States. However, the construction and continued existence of these lines have dramatic effects on the soil they are placed in. Theresa Brehm, a second-year master’s student in soil science, investigated these effects and recently presented her research findings with the Ohio State Energy Outreach Program.
Brehm and her advisor Steve Culman wanted to specifically determine the impact of pipeline installation on crop yields and soil properties in Ohio. Previous studies have explored similar effects across the globe, but Brehm’s is one of the first to dive deep into Ohio’s agricultural context. The team sampled 24 sites across 7 counties around the Rover, Utopia and Nexus pipelines. The samples contained grain crops such as soybean, corn grain and corn silage that had been planted throughout.
Brehm had five major categories of interest variables she wanted to measure. The first category, physical, consists of penetration resistance, aggregate stability and texture. The second, chemical, includes cation exchange capacity (how many cations a soil particle can hold on its surface) and nutrient level. Category three, biological, looks at active carbon level, proteins and respiration. The fourth group evaluates yield, both hand-harvested and remotely measured. The final category focuses on farmer experience, using surveys to obtain data for analysis.
The results of the study corresponded with the initial prediction. Corn and corn silage yield both decreased by over 20% while soybean yield decreased by roughly seven percent. The corn ears also tended to be smaller and misshapen. Soil compaction levels were higher than average, and in some locations, the researchers couldn’t even break ground because the particles were so tightly packed together. Mean aggregate weight, soil protein, soil carbon and soil nitrogen all decreased as well.
In her overview, Brehm surmised that average crop yields are lower in row after pipeline installation due to altered soil physical, chemical and biological properties, especially penetration resistance and aggregate size and stability. The new field season begins in September 2021, and Brehm and Culman are excited to continue their work.