Master of Science, The Ohio State University, 2021, Environment and Natural Resources

Soil quality is defined as the soil's capacity to function within natural or managed ecosystems to sustain plant-animal-human health. It can be inferred from the quantification of soil properties which can be combined into a soil quality index (SQI). An SQI is a value that combines soil physical, chemical, and biological characteristics and scores the soil's “fitness to function”. Soil management practices (SMP), which differ depending on the landholder's agenda, can increase or decrease soil carbon (C) storage, which is an important parameter used for SQI calculation. Therefore, the objectives of this study were: (1) to evaluate the impact of SMP on physicochemical properties in an avocado orchard (AVO) and a tropical pumpkin/bean (TPB) plot and (2) to develop an SQI for each system. The study was conducted in the Juana Diaz Agricultural Experimental Station located in the south-central coast of Puerto Rico and the predominant soil series was San Anton. Both systems scored 0.55 on the 0 to 1 SQI scale, suggesting that higher soil C content does not imply an improvement in soil physicochemical quality. However, reduced tillage operations and natural ground cover have a positive impact on soil quality indicators, but not on soil physicochemical quality itself for this study. Future research priorities should be directed towards the evaluation of soil taxonomical characterization on soil quality and determine its significance if any.

Committee: Rattan Lal Dr. (Advisor); Jeffory Hattey Dr. (Committee Member); Roger Williams Dr. (Committee Member); David Sotomayor Dr. (Committee Member) Subjects: Agriculture; Agronomy; Environmental Studies; Horticulture; Soil Sciences

Master of Science in Biological Sciences, Youngstown State University, 2022, Department of Biological Sciences and Chemistry

Biological soil crusts are clumped together communities of organisms with soils that play an essential role in arid ecosystems. They have crucial roles in primary roductivity, nitrogen and carbon cycling, mineralization, water retention, and soil stabilization. There is a gap in knowledge for desert crusts from the Cieneguilla Desert of Lima, Peru. This study measures metal concentrations and determines carbon/nitrogen associated with crust communities to characterize the BSC and establish potential biogeochemical relationships. Chapter 2: The importance of monitoring water quality is essential to maintaining healthy aquatic environments for wildlife and human health. This study of Yellow, Creek in Poland, Ohio aims to identify spatial and temporal trends in physicochemical parameters, biological indicators, and benthic community structure. Water quality parameters (temperature, dissolved oxygen, conductivity, total suspended solids, and fecal coliform count) were measured using a YSI Pro 2030 or other standard methods Nitrate, sulfate, and phosphate were measured using LaMotte nutrient kits. Macroinvertebrates were sampled using a 0.3 x 0.3 m Surber sampler. A two-way MANOVA of water quality parameters showed that season had significant influence on water quality. A one-way MANOVA showed that benthic macroinvertebrate community structure (density, diversity, and EPT richness) had a significant site*season interaction. Most physico-chemical and biological parameters were below maximum limits allowed by Ohio administrative code, but fecal coliform levels depended on season.

Committee: Thomas Diggins PhD (Advisor); Gloria Johnston PhD (Committee Member); Felicia Armstrong PhD (Committee Member) Subjects: Biology; Environmental Studies

Doctor of Philosophy, The Ohio State University, 2024, Environment and Natural Resources

Soil physical properties play a crucial role in agricultural productivity and environmental sustainability. This study investigated the seasonal dynamics of soil physical properties under different tillage and drainage practices in poorly drained soils of Ohio, focusing on their interrelationships with soil structure, crop growth, and climate across various agricultural production stages. Soils were sampled under long-term tillage (no-till, NT vs chisel-till, T) and drainage (drained, D vs non-drained, ND) management. Intact soil cores and undisturbed bulk samples were collected at 3 depths in different seasons. The research examined a. soil hydraulic properties, including saturated hydraulic conductivity (Ksat), unsaturated hydraulic conductivity (Ks) and water diffusivity (Ds) at field capacity, field infiltration, and plant available water capacity (AWC), b. soil structure, including bulk density (BD), pore size distribution (PSD), water stable aggregates (WSA), mean weight diameter (MWD), penetration resistance (PR), and aggregate tensile strength (TS), c. soil physical quality index (SQI) with the selected indicators, and d. crop development and climate factors, including crop height, crop yield, ground coverage, air temperature, daily precipitation, and rainfall intensity. Specifically, this thesis aims to: a. Investigate the dynamics of soil hydraulic properties (Ksat, Ks, Ds, field infiltration, AWC) under different tillage and drainage practices. b. Assess the dynamics of soil structure (WSA, MWD, PSD, PR, TS) under different tillage and drainage practices. c. Determine the yield-oriented SQI across different seasons of crop production. In terms of the first objective, results in Chapter 2 showed that NT generally maintained higher Ksat (0.675-0.898 cm/hr vs 0.307-0.572 cm/hr, p=0.001-0.124) in fallowing seasons, especially in surface soils, due to better soil aggregation and ground coverage. However, during growing seasons, NT (0.326-0.774 cm/hr) (open full item for complete abstract)

Committee: Rattan Lal (Advisor); Brian Slater (Advisor); M. Scott Demyan (Committee Member) Subjects: Agriculture; Environmental Science; Natural Resource Management; Soil Sciences; Sustainability

Doctor of Philosophy, The Ohio State University, 2024, Food, Agricultural and Biological Engineering

Worldwide urbanization and the concurrent increase in impermeable surfaces, such as parking lots, driveways, sidewalks, and other structures, have led to challenges managing runoff in cities. Improperly managed stormwater poses threats to public health, private property, and the environment. Countries worldwide are adopting the use of nature-based approaches known as green infrastructure (GI) to holistically treat environmental stressors resulting from urban development. GI is designed to mimic the natural, pre-development hydrology of the developed area while concurrently improving runoff quality. There are several GI approaches, including permeable pavements (PP), bioretention cells (BRC), and constructed stormwater wetlands (CSW), which can reduce runoff volume, delay and extend runoff timing, improve discharge water quality, and mitigate peak runoff rates from highly impervious catchments. PPs have been used worldwide for decades, but these systems remain infrequently implemented for stormwater management because of ambiguity related to maintaining their long-term hydraulic functionality due to clogging which reduces the PP surface infiltration rate (SIR) and therefore its performance. Measurements of the SIR can inform the extent of clogging, but at present there is a dearth of guidance on how to incorporate SIR data into dynamic PP maintenance plans. In the first chapter of my dissertation, I conducted a review of existing guidance documents to describe the current state of practice for SIR measurement methodologies, PP maintenance guidance, and the use of SIR outcomes to inform PP maintenance plans. Standard and alternative SIR assessment methodologies were described and compared, and modifications and recommendations were provided to clarify testing methods, streamline testing efficiency, and reduce the burden of SIR monitoring. Suggested modifications included requiring regular SIR testing, shortening the duration of SIR tests, and allowing for usage of mo (open full item for complete abstract)

Committee: Ryan Winston (Advisor); Jay Dorsey (Committee Member); Jon Witter (Committee Member); Jiyoung Lee (Committee Member); Jay Martin (Committee Member) Subjects: Ecology; Environmental Engineering; Environmental Management; Hydrology; Microbiology; Water Resource Management

Doctor of Philosophy, The Ohio State University, 2023, Environmental Science

Growing annual crops such as corn can lead to considerable nutrient losses through subsurface drainage in agricultural fields, posing a serious threat to surface water quality in the Midwest USA. Perennial crops have the potential to reduce these nutrient losses. However, more comprehensive data are needed on the nutrient loss effect of perennial crops. In the first chapter of my research, we examined the effect of alfalfa (Medicago sativa L.) on nitrate-nitrogen (NO3--N), total nitrogen (TN), dissolved reactive phosphorus (DRP), and total phosphorus (TP) in subsurface drainage using a Before-After-Control-Impact (BACI) experimental design with one control field (annual crops) and one impact field (with alfalfa) each on two farms (site A and B) located in northwest Ohio. The before period (prior to planting alfalfa at the impact field) extended for four years (2013-2017) at site A and six years (2011-2017) at site B, then the after period extended for an additional two years at both sites Reductions in the mean monthly discharge and loads of NO3--N, TN, DRP, and TP were significant at site A, while the only significant change at site B was a reduction in the mean monthly TP load. In the second chapter of my dissertation, we examined the effect of alfalfa on subsurface nitrogen (N) and phosphorus (P) loads across different storm event types. A k-median cluster analysis was employed to classify 462 storm events at site A and 684 storm events at site B that occurred between 2011 and 2019 based on precipitation amount and wet antecedent moisture conditions (AMC). Subsequently, a difference-in-differences analysis was conducted to compare patterns of nutrient loss in tile drainage between fields with alfalfa and fields without alfalfa across three identified storm event types: Moderate-dry storm events (events with precipitation amount ≤ 34 mm, and wet AMC ≤ 27 mm), moderate-wet storm events (events with precipitation amount ≤ 39 mm, and wet AMC > 27 mm), and large st (open full item for complete abstract)

Committee: Jay Martin (Advisor); Margaret Kalcic (Advisor); Marilia Chiavegato (Committee Member); Steven Quiring (Committee Member); Steven Lyon (Committee Member); Kevin King (Committee Member) Subjects: Climate Change; Environmental Science; Hydrology; Water Resource Management

Bachelor of Science, Wittenberg University, 2023, Biology

This study investigates the soil quality and plant diversity of a discontinued golf course in Springfield, Ohio, with the aim of assessing its potential for restoration. Led by the National Trail Parks & Recreation District, the restoration plans for Snyder Park include the establishment of wet meadows, prairies, and woodlands, which can thrive in the natural hydric soils of the former golf course. In this study, baseline soil data was collected using GIS and GPS technologies, analyzing soil texture, carbon content, nitrate nitrogen, phosphorous, potassium, replaceable calcium, humus, and pH. Plant diversity was evaluated through random sampling of quadrats. Initial observations revealed patches dominated by specific plant species, and a comparison of soil and plant characteristics across elevations was conducted. The golf course mainly consisted of the Westland soil series, which supports water retention. However, deficiencies in humus and low levels of potassium and nitrate nitrogen pose challenges for restoration. Limited native plant species adapted to moist conditions were observed, suggesting ongoing recovery from intensive land management. To sustain a natural wetland or floodplain ecosystem, restoration efforts should focus on introducing native wetland species and providing nutrient inputs, mainly nitrogen and potassium. The Snyder Park golf course holds potential for restoration, but additional measures are necessary for a successful habitat transition.

Committee: John Ritter (Advisor); Nona Moskowitz (Committee Member); Matthew Collier (Committee Member) Subjects: Ecology; Environmental Science; Environmental Studies; Horticulture; Soil Sciences

Master of Science, The Ohio State University, 2023, Food, Agricultural and Biological Engineering

Interest in agricultural soil health and quality has encouraged farmers across the world to adopt soil health management practices, such as no-till or reduced tillage and cover crops. In-spite of the growing adoption of soil health practices, few studies have focused on their impact on soil and water quality after long-term adoption. To assess the effects of soil health practices, soil and water samples were collected over two years from three paired sites, each representing three different land use management scenarios: (1) agricultural fields with conventional crop rotation and management, (2) agricultural fields with 15 to 45 years of soil health management adoption, and (3) forest soils near each pair of agricultural fields. A combination of 52 soil health indicators were analysed including: microbial communities, enzyme activities, phospholipid fatty acid (PLFA), soil respiration, bulk density, macronutrients, and micronutrients. Edge-of-field and surface runoff analysis included total nitrogen (TN), total phosphorus (TP), nitrate, and dissolved reactive phosphorous concentrations during dry and wet periods over the course of a year. Results suggest that long-term soil health management had little impact on soil health indicators when compared to conventionally managed farms but did reduce TP, TP, nitrate leaching, and water loss. However, further evaluation of the soil health indicators revealed some promising relationships between soil health and water quality. When compared to the forested systems, both agricultural systems were found to have significantly lower biological quality. These results provide some evidence to support the implementation of soil health practices in agricultural fields and a perspective on long-term agricultural management practices compared to native natural soil health.

Committee: Ryan Winston (Advisor); Vinayak Shedekar (Committee Member); William Osterholz (Committee Member) Subjects: Agriculture; Environmental Engineering; Hydrologic Sciences; Soil Sciences; Water Resource Management

Doctor of Philosophy, The Ohio State University, 2021, Environmental Science

The 2016 revision to the Great Lakes Water Quality Agreement set forth water quality targets for Lake Erie. The revised binational agreement calls for a 40% reduction in Total Phosphorus (TP) and Dissolved Reactive Phosphorus (DRP) from 2008 loads from the Maumee River watershed to be met nine-years-out-of-ten. Previous studies have shown that widespread implementation of agricultural conservation practices (CPs) is needed to reach or approach these targets. Watershed modeling can play an important role in informing policies that aim to increase the adoption rates of agricultural CPs. However, watershed modelling efforts typically exclude important information derived from social science studies, such as farmer surveys (e.g., what factors affect farmers in adopting certain agricultural CPs). This work takes an interdisciplinary and multi-disciplinary approach to examine agricultural CP adoption in the Maumee River watershed to improve the integration between data derived from farmer surveys and watershed modeling and historically examine state efforts aimed to increase agricultural CP adoption across Ohio. Conservation identities, perceived response efficacy of subsurface phosphorus placement, level of education, years of farming experience and other demographic, farm-operational, and psychological characteristics, derived from the farmer survey, were embedded into a SWAT model of the watershed. Modeled farm operations, created with near field-level Hydrologic Response Units (HRUs) within the SWAT model, were assigned a modeled primary operator and assigned demographic, farm-operational, and psychological characteristics informed by the farmer-survey. Integrating the farmer survey data and the SWAT model allowed for novel approaches in targeting the placement of buffer strips and subsurface phosphorus fertilizer placement in the SWAT model. Model results indicate that near optimal water quality results can be obtained for both buffer strips and subsurface phosph (open full item for complete abstract)

Committee: Jay Martin (Advisor); Nicholas Breyfogle (Committee Member); Margaret Kalcic (Committee Member); Douglas Jackson-Smith (Committee Member) Subjects: Agricultural Engineering; Environmental Management; Environmental Science; History

Master of Science in Environmental Science, Youngstown State University, 2021, Department of Physics, Astronomy, Geology and Environmental Sciences

Although frequently overlooked or omitted, ecosystem services provide an environment for the survival of life on earth, including humans. Soil is a critical compartment for ecosystem services composed of solids, gasses, water, and micro and macro flora and fauna. Soil functions include water holding capacity, nutrient holding and cycling, support for microbial life, carbon capture, and other many other unseen benefits. Within society a main use of soil is agriculture for growth of food, fiber, and other necessities for civilization. Agricultural practices can consist of different techniques, two common categories are conventional and conservation methods. Conventional tillage utilizes turning of the soil to prepare the seedbed and remove unwanted plants. In conservation methods the use of no tillage or reduce tillage is used, where the soil is minimally disturbed, and the seeds are inserted into small slits or openings. Aggressive tillage can affect soil ecosystem function and limit the quality of soil health by decreasing porosity, reducing microbial processes, and increasing erosion. Seven farm fields in Trumbull County, OH, were sampled to investigate the connection between agricultural method and soil quality characteristics that contribute to overall soil health and productivity. Composite soil samples consisting of 2.5 cm soil cores separated into top 15 cm layer and bottom layer were evaluated for organic matter, bulk density, soil texture, plant available phosphorus, pH, total nitrogen, salinity, and percent porosity using standard methods. The data composed of 32 samples, with 16 samples from the top layer and 16 from the bottom layer. The fields were ranked one to four, with a ranking of one indicating conventional methods to ranking of four with the highest amount of conservation practices applied. Statistical analyses included descriptive statistics, mean comparison, one-way ANOVA, Principal Component Analysis, and backwards linear regressions using S (open full item for complete abstract)

Committee: Felicia Armstrong PhD (Advisor); Colleen McLean PhD (Committee Member); Albert Sumell PhD (Committee Member); Lee Beers MS (Committee Member) Subjects: Agricultural Economics; Agricultural Education; Agriculture; Agronomy; Earth; Economic Theory; Environmental Economics; Environmental Education; Environmental Health; Environmental Philosophy; Environmental Science; Environmental Studies; Soil Sciences; Sustainability

BS, Kent State University, 2020, College of Arts and Sciences / Department of Biological Sciences

The increasing urbanization of land has produced expansive amounts of impervious surfaces, yielding greater quantities of runoff. This runoff can carry pollutants from the surrounding area into the water system and negatively impact the water quality. A possible solution for reducing runoff from impervious surfaces is green roofs, which can absorb and filter water. To determine a green roof's effects on water quantity and quality, an experimental green roof was studied in Cleveland, Ohio. This site contains 39 test plots that differ in combinations of plant community type (restoration or horticultural), substrate type (quasi-traditional, conventional, or open space), and the presence of mycorrhizal inoculum. From October 2017 to October 2018, water samples were collected bimonthly, along with volumetric measurements of the runoff present. The samples were tested for inorganic phosphorus and total inorganic nitrogen using nutrient assays on a microplate reader. Over the duration of the experiment, total inorganic nitrogen fluxes and concentrations were too low to be of concern. Inorganic phosphorus fluxes and concentrations were initially high, but decreased as the roof aged. Building and collection materials were analyzed for phosphorus leaching, but results rather showed possible phosphorus adsorption to certain materials. Inorganic phosphorus was most heavily influenced by substrate type and may be reduced by the use of natural, non-fertilized substrates. Total inorganic nitrogen was most heavily influenced by the biological components (plant community, mycorrhizae), and may be reduced by the presence of mycorrhizae. Manipulating design aspects of green roofs may increase their potential to be improved and refined into an efficient environmental resource.

Committee: Christopher Blackwood Ph.D. (Advisor); David Costello Ph.D. (Committee Member); Reid Coffman Ph.D. (Committee Member); Mark Kershner Ph.D. (Committee Member) Subjects: Biology; Ecology; Environmental Engineering; Environmental Science; Sustainability

Master of Science, The Ohio State University, 2019, Horticulture and Crop Science

Constructing athletic fields on a sand base allows for more rapid drainage; however, lateral shear strength and traffic tolerance tends to not be as good as that of a native soil field. Hybrid turf systems were developed that intertwine turfgrass with synthetic fibers that are able to improve shear strength. Hybrid systems are used on sports fields ranging from practice fields to competition fields globally. Previous stabilization systems included fibers that were shorter than the intended height of cut of the turfgrass. The purpose of this study was to test a new system which has the natural turf maintained at the same height as the synthetic fibers. The project's main goal was to compare two hybrid turf systems constructed in combination with two different types of sand (round vs angular), and three turf species to determine which leads to the highest performance for elite level soccer matches, while also keeping player safety in mind. Measurements and treatments taken to achieve these goals included Gmax, traffic, quality, soil moisture and shear strength both rotational and lateral. All measurements and data were taken at the project's field site at the Ohio Turfgrass Foundation (OTF) research facility over the course of two years. Results indicated that turf species was ultimately the most significant factor, with both hybrid carpets doing their intended job and sand shape playing a much smaller roll than initially anticipated on overall results. The HERO hybrid system in conjunction with angular sand and ryegrass was the overall best combination for elite level soccer teams to be able to have both safer fields and higher levels of player performance.

Committee: David Gardner Dr. (Advisor) Subjects: Agronomy; Horticulture

Master of Science, The Ohio State University, 2019, Environment and Natural Resources

Conservation practices, such as no-till and diversifying crop rotations are known for their capacity to reduce soil erosion and improve soil properties. However, the impact of these management practices on emerging soil health tests and the ability of these tests to reflect active organic matter dynamics and nutrient cycling, and corn productivity has not been explored. This project focused on determining the effects of half a century of continuous tillage treatments (moldboard plow, chisel till, and no-till) and crop rotations (continuous corn, corn-soybean, and corn-forage-forage) on soil health indicators and its relationship with crop productivity. The forages were alfalfa in Wooster and red clover and oats in Northwest. Soil labile carbon (C) and nitrogen (N) temporal dynamics were quantified with permanganate oxidizable C (POXC), mineralizable carbon (Min C), and soil protein at six key stages in corn (Zea mays) development: before planting (around three weeks before planting), V5, V10, R1, R4, R6 in the 2017 and 2018 growing seasons. Corn leaf chlorophyll, aboveground plant biomass, nutrient uptake, and grain yield were also quantified. The soil health indicators (POXC, Min C, soil protein) and crop parameters (leaf chlorophyll, total nitrogen uptake, and total aboveground biomass) were higher in reduced tillage (chisel and no-till) compared to moldboard plow and higher in the most diverse crop rotation (corn-forage-forage) compared to corn-soybean. Corn yields were not significantly different between tillage treatments but were higher in the more diverse rotations (corn-soybean and corn-forage-forage) compared to corn monoculture. Although the treatment effects varied by site and year, rotation had a consistently larger effect on soil health indicators and corn productivity than tillage, highlighting the importance of including crop rotations in corn production. We conclude that Ohio soils under half a century of continuous tillage and rotation treatments ha (open full item for complete abstract)

Committee: Steve Culman PhD (Advisor); M.Scott Demyan PhD (Committee Member); Peter Thomison PhD (Committee Member) Subjects: Agriculture; Agronomy; Soil Sciences

Master of Science, The Ohio State University, 2018, Environment and Natural Resources

Maize (Zea mays L.) is the principal food source for Eastern Africa's rising populations. In Morogoro Region, Tanzania, 56% of agricultural land is cropped with maize and 90% of its people are smallholder farmers. For these reasons, understanding the relationship between crop management decisions, agricultural soil quality, and maize yield is of critical importance. Field management practices were recorded during the November – January (short) rainy season crop, and the March – June (long) rainy season, and water use during the short rainy season. Soil samples were taken from each field in June 2017 and analyzed for soil quality parameters pH, total nitrogen (TN), soil organic carbon (SOC), bulk density (BD), texture, aggregate stability (AS), and penetration resistance. Analyses indicated that during both the short and long rainy seasons, maize production resulted in a lower pH than in vegetable production, or maize – cowpea intercrop. Fields which were cropped with maize in the long rainy season had higher clay content (Clay) than did those cropped with a maize – cowpea intercrop. Sand content (Sand) appeared to be higher in fields cropped with a maize – cowpea intercrop in maize in the long rainy season. Textural variation was accounted for a spatial gradient in soil series, which likely informed crop choice. Aggregate stability was found to be higher in fields cropped with maize in the short rainy season than with vegetable. TN, SOC, BD, silt content (Silt), and penetration resistance were not found to vary between iii crop management practice. Each soil quality parameter was entered into a linear regression model and a mixed effects model with long rainy season maize yields to determine the property's association with maize production. These analyses indicated that BD and sand concentration were negatively affecting maize yields while silt concentration, and to a lesser extent, SOC and AS were positiv (open full item for complete abstract)

Committee: Rattan Lal PhD (Advisor); Jeffory Hattey PhD (Committee Member); Stephen Culman PhD (Committee Member); Mark Erbaugh PhD (Committee Member) Subjects: Agricultural Chemicals; Agriculture; Agronomy; Soil Sciences

Ph.D., Antioch University, 2018, Antioch New England: Environmental Studies

Climate change and crop intensification are key challenges to the livelihoods and wellbeing of the majority of rural smallholder farmers in developing countries, particularly in human-dominated, climate-sensitive landscapes such as the northern highlands of Rwanda where issues of fluvial floods, soil erosion pose serious threats to the livelihoods of smallholder farmers. In this mixed methods study conducted between August and December 2015, I explored smallholder farmers' perceptions by examining what barriers might hinder the process of agroforestry adoption by smallholder farmers, what socio-economic and physical factors and attitudes influence crop choices, motivations for smallholder farmers' willingness to plant trees within riparian buffer zones and opportunities and challenges to the establishment of riparian buffer zones that maintain ecosystem services. Results indicate that challenges to adoption of agroforestry to support climate change adaptation and food security in Rwanda are related to land scarcity, poverty, limited technological and financial capacity among most smallholder farmers, limited engagement of smallholder farmers in agroforestry research and an inclination for short term benefits that could hinder adoption of agroforestry which has a long term investment. Most smallholder farmers believed that the onset of short rains comes earlier in recent years compared to more than ten years ago. In response, most farmers reported that they plant crops earlier in the season. Results from rainfall analysis, although not conclusive, show a shift in rainy day frequency. Respondents who strongly agreed that soil erosion within farms proximal to streams is a serious threat were more likely to support the idea that establishing a riparian buffer would help entrap sediments and mitigate soil erosion within farmlands adjacent to streams. However, farmers reported that establishing a functional riparian buffer requires engagement with extension services, fi (open full item for complete abstract)

Committee: Beth Kaplin Ph.D. (Committee Chair); James Gruber Ph.D. (Committee Member); Joel Hartter Ph.D. (Committee Member) Subjects: Agriculture; Environmental Management; Environmental Science; Environmental Studies; Forestry; Water Resource Management

MS, Kent State University, 2018, College of Arts and Sciences / Department of Earth Sciences

In urban areas, increased runoff from storm events is a significant concern due to flooding, erosion, ecosystem disturbance, and water quality problems. Phosphorus (P) and nitrogen (N) are key limiting nutrients that lead to eutrophication and harmful algal blooms in Lake Erie and other freshwater systems, and urban landscapes are locally important sources of nutrients to downstream water bodies. Green infrastructure (GI) is one increasingly popular solution being used in urban areas to address the water quantity and quality issues that urban runoff creates. Green roofs and bioretention cells are widely used forms of GI designed to decrease and slow down runoff through evapotranspiration and infiltration. I compared the hydrologic effectiveness of a co-located extensive green roof and two bioretention cells in northeastern Ohio, in order to understand their relative capacities to decrease and slow down stormwater runoff, when subjected to the same weather conditions. I also monitored the green roof to understand its effects on water quality, in terms of P and N. From June 2015 to November 2016, 93 storms from 2.5 to 62 mm, were monitored. To assess the hydrologic performance of each site, I measured rainfall, underdrained outflow, groundwater levels in the bioretention cells, and soil moisture on 1–5 minute intervals. To assess water quality for the green roof, I collected precipitation and samples from the green roof downspout. I measured chloride (Cl-) phosphate (PO43-), total P, nitrate (NO3-), ammonium (NH4+), and total N concentrations using ion chromatography and a colorimetric assay. The bioretention cells performed similarly to each other, despite slightly different designs, and they had superior performance to the green roof. The paved lot bioretention cell showed 77% volumetric and 85% peak flow reduction and the gravel lot bioretention cell showed 78% volumetric and 82% peak flow reduction. The green roof only reduced 59% of its water input and 69% (open full item for complete abstract)

Committee: Anne Jefferson (Advisor); Lauren Kinsman-Costello (Advisor); Elizabeth Herndon (Committee Member) Subjects: Ecology; Environmental Science; Geology; Hydrology; Sustainability; Water Resource Management

Master of Science, The Ohio State University, 2018, Horticulture and Crop Science

In Ohio, many organic farmers use the term `balancing' to express the rationale of using a wide variety of soil amendments to improve soil quality and plant health. Soil balancing or the base cation saturation ratio (BCSR) approach is a method first proposed more than 100 years ago that aims to achieve the `ideal soil'. William Albrecht in the 1970's concluded that if saturation of the major exchangeable cations is 65-85% for Ca, 6-12% for Mg, and 2-5% for K, plant nutrition will be balanced. Research conducted by Zwickle et al. (2011) indicated that many organic farmers believe balanced soils produce higher quality crops and have diminished weed infestations compared to unbalanced soils. For many farmers, soil balancing includes using amendments thought to enhance soil biology and increase the soil's capacity to store and release minerals needed by plants. Combined mineral and these organic/bio-active soil products can be very costly, as much as US $1000-1250/ha in the first year. While farmers believe they are benefiting from these expenditures, there is no objective evidence to confirm their belief. I conducted on-farm studies at six locations in Northeast Ohio, with the overall goal of determining the effect of gypsum, with or without “biological stimulants”, on the soil microbial community, crop quality, weed populations, and soil chemical characteristics. Soil seed bank and soil health/biological properties were measured, including soil respiration, active carbon, protein content, microbial biomass, and complete mineral analysis. Crop foliage for nutrient analysis, and crop quality was determined after harvest. Differences in final soil nutrient levels, base saturation, crop and weed community effects were influenced more by the farm than by the treatments applied. After two years, soil sulfur levels were significantly higher in plots amended with gypsum. Failure to detect treatment response by other mineral amendments suggests the relatively narrow difference (open full item for complete abstract)

Committee: Douglas Doohan (Advisor); Warren DIck (Committee Member); Kleinhenz Matthew (Committee Member); Steve Culman (Committee Member) Subjects: Agriculture; Horticulture; Soil Sciences

Master of Science, The Ohio State University, 2017, Environment and Natural Resources

Soil quality has been defined by Doran and Parkin (1996) as the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health. A multitude of physical, chemical, and biological parameters can be assessed to provide a comprehensive picture of soil quality. The overall objective of this study was to evaluate long term soil restoration and development of manufactured soil dredge blends by using these soil quality parameters. Chapter 1 assessed the soil quality of an urban site treated with biosolids or compost by comparing data collected over years of sampling after one initial application of the treatments. The results show that biosolids-based treatments leads to overall greater long-term soil quality than compost treatments. However, soil phosphorus in the biosolids-treated soils were of concern for runoff and surface water quality harm. Therefore, the study concludes that no treatment was the ideal amendment for overall improved soil quality, and that a blend of compost and biosolids together could be of interest in future research. In Chapter 2, soil quality parameters were used to assess dredge as a main ingredient in manufactured soil blends. With Ohio regulation changing how dredge must be disposed of, research into the beneficial reuse of soil-like dredge material is vital. Blends were designed by incorporating dredge materials, composts and clay then followed by a bioassay growing rye grass. Interestingly, the smaller size fraction dredge material, which is believed to be unsuitable for reuse, resulted in greater soil quality for the majority of the parameters. The addition of a compost material improved the blends, while clay and fertilizer additions did not result in greater soil quality or plant yield. Dredge showed to be a suitable material in manufactured soil blends for beneficial reuse.

Committee: Nicholas Basta PhD (Advisor); Brian Slater PhD (Committee Member); G. Matthew Davies PhD (Committee Member) Subjects: Environmental Science; Environmental Studies; Soil Sciences

Doctor of Philosophy, The Ohio State University, 2017, Environmental Science

Carbon dioxide concentration is increasing in the atmosphere. This has encouraged the world community to change its energy usages from a fossil resource-based that currently dominates to a renewable bio-based in the future. This opened the door for “solutions from the land” which has led to exploration of land used in the Conservation Reserve Program (CRP) with mixed prairie plant genomes. CRP, a massive public-private partnership program was instituted in 1985 and has reached a total enrolment of about ~10 million hectares that has not been harvested during the past 30 years. Much of the CRP land has degraded, resulting in reduced land cover and a net loss of primary productivity. This research is based on the premise that CRP lands can be harvested for to supply biofuel feedstocks or forage for livestock without long term harmful effects on the plant community and soil environment and without compromising wildlife habitats. This may lead to a Win-Win situation where lignocellulosic materials can be harvested from the CRP lands while at the same time protecting wildlife habitat. In 2009, CRP land located near Piketon, OH was selected for this study. The site was planted in 1999 with nine different warm-season perennials in a prairie mix that had not been harvested for ten years. The site was burned once in 2009 to get rid of weeds and brambles. Treatments imposed on this land in 2009 were designed to test the effect of N fertilization and harvest timing and frequency on the response of CRP land. Five levels of N (0, 10, 20, 40 and 80 kg N ha-1) and three management strategies (A: Harvest in March or April; B: 1st harvest in May, and 2nd harvest in March or April; and C: Multiple harvests during May through October) with four replications in a factorial randomized complete block design with a strip-block restriction on treatment randomization. Energy yields (GJ ha-1 yr-1) increased from 96.0 in 2009 to 287.0 in 2014 with Management-A, 83.0 in 2009 to 202 in 2014 (open full item for complete abstract)

Committee: R. Mark Sulc Ph.D. (Advisor); Warren Dick Ph.D. (Committee Co-Chair); Richard Moore Ph.D. (Committee Member); Norman Fausey Ph.D. (Committee Member) Subjects: Environmental Science; Natural Resource Management; Soil Sciences

Doctor of Philosophy, The Ohio State University, 2016, Environmental Science

Over 70% of Tanzanians live on less that $2 per day and over 75% of the population is involved in agriculture. Increasing agricultural productivity is seen as a way to decrease poverty and stimulate the economy. Sustainable Intensification (SI) is widely promoted as a means to sustainably increase agricultural production for smallholder farmers. Practices considered being SI should increase productivity on the same land with more efficient use of resources, in a way that minimizes negative effects on the environment. The objectives of these studies were to evaluate SI practices for their effect on agronomic productivity and soil quality for smallholder farmers in Tanzania. Further, these studies sought to identify the impact that these practices have on smallholder farmer profitability and water management within an irrigation scheme. These objectives were achieved through experiments carried out at three locations over three growing seasons within the Lower Moshi Irrigation Scheme (LMIS) in Mabogini Village, Kilimanjaro Region, United Republic of Tanzania. The studies each evaluated improved cropping systems that are appropriate for various areas within the scheme. The first three studies evaluated the System of Rice Intensification (SRI), crop rotations and nutrient management strategies, and reduced tillage for their effect on agronomic productivity and soil quality. Two further studies evaluated the profitability of SRI and the occurrence of dry spells in the region and the implications this has for rainfed maize (Zea mayes) production. Within continuous rice (Oryza sativa), SRI and conventional had similar yields to those under conventional practices in the region except for during the last season, in which SRI systems yielded on average 1.25 Mg ha-1 higher than conventional systems. If SRI is adopted throughout the LMIS, there is potential to increase rice production by 4,173 Mg due to increased water use efficiency and the ability to increase the area unde (open full item for complete abstract)

Committee: Lal Rattan (Advisor) Subjects: Agronomy; Soil Sciences

Master of Science, The Ohio State University, 2016, Environmental Science

The west-central region of Ohio is one of the most productive agricultural regions of the state and has notable economic importance. Past and projected climatic changes bring a significant amount of variability into the future productivity of this specific region and place an importance on protecting soil resources. The objectives of this study were to examine the effects of common management practices, including Best Management Practices (BMPs), in West-Central Ohio on key soil properties supporting overall soil quality, the productivity of soils under such practices, and the feasibility of using the Soil Management and Assessment Framework (SMAF) to evaluate soil quality in the region. On-farm study sites were established representing examples of conventional tillage (CT), no-till (NT), no-till with manure application (NT-M), and no-till with cover crops (NT-CC) common to the region. Significant differences were found among all measured soil properties, except available water capacity (AWC), steady state infiltration, and water stable aggregation (WSA). Despite this, evidence was found to support improved aggregate stability under cover crops. The NT and NT-CC sites were shown to have increased large pore formation, mean weight diameter (MWD), and saturated hydraulic conductivity (Ks) even though they possessed higher bulk density in the upper soil profile. The distribution and concentration of soil organic carbon (SOC) were both affected under the BMPs studied. Particularly at the NT site, an increase in the SOC concentration and stock was seen in the 0-10 cm depth but below this point the CT site had equal to greater SOC concentrations and stock when compared to the no-till sites. The NT-CC site was found to have the lowest overall SOC stock but conclusions concerning the results from the lower soil depths were limited due to variability within the subsoil or past management at the NT-CC site. Differences were found in yield and calculated harvest index (HI) fo (open full item for complete abstract)

Committee: Rattan Lal (Advisor); Dick Warren (Committee Member); Phausey Norman (Committee Member) Subjects: Agriculture; Agronomy; Natural Resource Management; Soil Sciences