University of Arkansas, Fayetteville ScholarWorks@UARK Theses and Dissertations 12-2018 Assessment of Soil Properties and Vegetation in a Mounded Native Tallgrass Prairie with an Aquic and Udic Soil Moisture Regime in the Ozark Highlands Region of Northwest Arkansas Tyler Joseph Durre University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/etd Part of the Environmental Indicators and Impact Assessment Commons, Environmental Monitoring Commons, and the Soil Science Commons Recommended Citation Durre, Tyler Joseph, "Assessment of Soil Properties and Vegetation in a Mounded Native Tallgrass Prairie with an Aquic and Udic Soil Moisture Regime in the Ozark Highlands Region of Northwest Arkansas" (2018). Theses and Dissertations. 3072. https://scholarworks.uark.edu/etd/3072 This Thesis is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ScholarWorks@UARK. For more information, please contact [email protected], [email protected]. Assessment of Soil Properties and Vegetation in a Mounded Native Tallgrass Prairie with an Aquic and Udic Soil Moisture Regime in the Ozark Highlands Region of Northwest Arkansas A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Crop, Soil, and Environmental Science by Tyler Durre University of Arkansas Bachelor of Science in Environmental, Soil, and Water Science, 2016 December 2018 University of Arkansas This thesis is approved for recommendation to the Graduate Council. ________________________________ Kristofor R. Brye, Ph.D. Thesis Director ________________________________ _________________________________ David M. Miller, Ph.D. Lisa S. Wood, Ph.D. Committee Member Committee Member ________________________________ Edward E. Gbur, Ph.D. Committee Member Abstract Native tallgrass prairies were once considered to be the dominant pre-settlement vegetation type in the eastern third of the Great Plains, but are now designated as America’s most endangered ecosystem due to conversion to agricultural land. Prairie mounds are unique soil features still present in remnant native tallgrass prairies across the United States. The main objective was to determine the effects of soil moisture regime (i.e., aquic and udic), mound position, (i.e., mound summit, backslope, toeslope, inter-mound), soil depth (i.e., 10-cm intervals from 0 to 90 cm), and their interactions on soil physical, chemical, and hydraulic properties in a mounded native tallgrass prairie in the Ozark Highlands region of northwest Arkansas. The secondary objective was to evaluate the effects of soil depth (i.e., 10, 20, 30, and 50 cm), mound position (i.e., mound summit and inter-mound), soil moisture regime (i.e., udic and aquic), and their interactions over time and to quantify the effects of soil moisture regime (i.e., udic and aquic), mound position (i.e., mound summit and inter-mound), sample date, and their interactions on prairie vegetation. Soil samples were collected in mid-April 2017, volumetric water content measurements were collected continuously from April 2017 – June 2018, and vegetation was sampled in June and August 2017 and in May and August 2018. Soil clay concentrations in the mound summits roughly doubled from 0-90 cm while the clay concentrations in the backslope, toeslope, and inter-mound increased by three to six times from 0-90 cm. The maximum soil volumetric water content for selected rainfall events was approximately 2.5 times greater at the 10-cm depth in the aquic inter-mound compared to the udic mound at 30 cm. Total aboveground dry matter was numerically largest (8489 kg ha-1) at the aquic summit in August 2018 and numerically smallest (1280 kg ha-1) at the aquic inter-mound in May 2018. The results of this study provide insight regarding soil nutrient contents and water dynamics of prairie mounds and inter-mound areas, which are important for plant growth. Results clearly demonstrate that prairie restoration/management activities need to account for mound topography and differing soil moisture regimes to be most successful. Acknowledgements I would like to thank the members of my Thesis Committee, Dr. Kristofor R. Brye, Dr. David M. Miller, Dr. Lisa S. Wood, and Dr. Edward E. Gbur for providing guidance throughout my research and the preparation of this thesis. I would like to thank Dr. Kristofor R. Brye for his guidance throughout my graduate career. I am thankful for the professional development opportunities Dr. Brye has provided over the last two years. I appreciate Dr. Brye’s commitment to teaching me how to conduct research and report my findings scientifically. I would like to thank Dr. David M. Miller for inspiring me to pursue soil science. After completing Introductory Soils, I knew I wanted to specialize in soil science. I thank Dr. Miller for answering questions and providing insight throughout my research. I would like to thank Dr. Lisa S. Wood for providing me the opportunity to serve as a Teaching Assistant throughout graduate school and serving as a mentor throughout my academic career. The advice and encouragement provided by Dr. Wood contributed to my success academically. I would like to thank Dr. Edward E. Gbur for assisting me with statistics throughout my research. Dr. Gbur’s thorough explanation of statistical procedures was instrumental to the completion of my thesis. I would like to thanks my parents for their support throughout my time at the University of Arkansas. My parents constant support and encouragement allowed me to succeed academically, and in all aspects of my life. Dedication This thesis is dedicated to my family and friends who supported and encouraged me throughout my academic career Table of Contents Introduction ................................................................................................................................... 1 References ...................................................................................................................................... 2 Chapter 1: Literature Review ...................................................................................................... 3 Tallgrass Prairie Distribution and Loss........................................................................................ 4 Climate ......................................................................................................................................... 4 Tallgrass Prairie Vegetation ......................................................................................................... 5 General Plant Composition ..................................................................................................... 5 Disturbance .................................................................................................................................. 6 Fire .......................................................................................................................................... 6 Soil Physical Properties .......................................................................................................... 7 Soil Chemical Properties......................................................................................................... 8 Soil Fertility ............................................................................................................................ 8 Vegetation ............................................................................................................................. 10 Native Grassland Soils ............................................................................................................... 11 Carbon ................................................................................................................................... 11 Nitrogen ................................................................................................................................ 14 Bulk Density ......................................................................................................................... 16 Organic Matter ...................................................................................................................... 17 Soil pH .................................................................................................................................. 19 Electrical Conductivity ......................................................................................................... 20 Soil Properties of Native Grasslands in the Ozark Highlands ................................................... 21 Overview ............................................................................................................................... 21 Analysis of Soil Physical and Chemical Properties .............................................................. 22 Mima Mound Distribution ......................................................................................................... 23 Mound Morphology ................................................................................................................... 23 Mound Formation Theories ....................................................................................................... 24 Fossorial Formation Hypotheses........................................................................................... 25 Erosion and Deposition ........................................................................................................