Date of Award

Fall 2026

Abstract

Climate change is threatening the stability of Earth’s food systems. Global temperatures are expected to rise by up to 4.8 °C by the end of the century, leading to a reduction in crop yields. This climate crisis is driven in part by emissions of carbon dioxide (CO2) and nitrous oxide (N2O) from agricultural systems. In order to face this challenge, we will need to employ agricultural management practices that allow for climate adaptation while also mitigating agriculture’s impact on the climate. Cover cropping is an emerging practice that has the potential to both improve soil health and offset greenhouse gas emissions from agricultural systems. However, cover crops also have the potential to increase soil greenhouse gas emissions under certain conditions. Further research is needed to better understand how greenhouse gas emissions from agricultural soils will be impacted by increasing temperatures and the use of cover cropping.In Chapter One, I introduce open-top chambers (OTCs) as a tool for simulating warming in agroecosystems. OTCs are a simple and versatile method for increasing air temperature in the field; however, their design poses some limitations. I use temperature and light data to examine how factors such as light intensity, season, and time of day may influence the magnitude of warming produced by the OTC. The results show a positive relationship between light intensity and difference in temperature (ΔT); however, the strength of this relationship varies by season. Additionally, the magnitude of warming is affected by a combination of month and time of day. Daytime ΔT is highest in the summer, while nighttime ΔT is highest in the winter. Despite producing a consistent warming effect in the winter, OTCs fall short of the magnitude of winter warming predicted by future climate models. OTCs show potential as a tool for simulating warming in agroecosystems, but may need to be paired with another warming method during the winter. In Chapter Two, I use OTCs as a tool to simulate warming during the fallow period in a silage corn agroecosystem. Three cover crop treatments were applied to the field: a no-cover control (NCC), winter rye (RYE), and an interseeded mix (MIX). Winter rye is a cold-tolerant cover crop commonly planted throughout the Northeast. Interseeded mix consists of two species of clover, annual ryegrass, and tillage radish. It was sown using a practice known as interseeding, in which cover crops are sown between rows of a cash crop during the growing season. I used the static chamber method for sampling greenhouse gas fluxes to capture emissions of CO2 and N2O from each of the treatments in spring of 2024 and 2025. The results show that warming significantly increases emissions of CO2 across the growing season and increases N2O emissions during specific “hot moments” of N2O production. Cover crop choice also plays an important role in controlling greenhouse gas emissions. The RYE treatment increases CO2 emissions on several dates, and one date shows higher N2O emissions under the MIX. While cover crops can increase direct greenhouse gas emissions, they offer other benefits to soil health and fertility which may indirectly offset greenhouse gas emissions, making it difficult to calculate their net impact.

Document Type

Master's Thesis

First Advisor

Richard Smith

Second Advisor

Alexandra Contosta

Department or Program

Natural Resources

Degree Name

Master of Science

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