Grant A. Harris fellowship (2011 recipients)


  • 2011 recipients

  • Michelle Newcomer

    Michelle Newcomer, San Francisco University

    Recharge rates beneath low-impact design rain gardens and the influence of El Niño southern oscillation on urban coastal groundwater resources

    Global groundwater resources in urban, coastal environments are highly vulnerable to increased human pressures and climate variability. Impervious surfaces, such as buildings, roads, and parking lots prevent infiltration, reduce recharge to underlying aquifers, and increase contaminants in surface runoff that often overflow sewage systems.

    To mitigate these effects, cities worldwide are adopting low impact design (LID) approaches that direct runoff into natural vegetated systems, such as rain gardens that reduce, filter, and slow storm water runoff and are hypothesized to increase infiltration and recharge rates to aquifers. The effects of LID on recharge rates and quality is unknown, particularly during intense precipitation events for cities along the Pacific coast in response to inter-annual variability of the El Niño Southern Oscillation (ENSO).

    Using METER water potential and soil moisture sensors, I will collect and monitor soil, hydraulic, and geochemical data to quantify the rates and quality of infiltration and recharge to the California Coastal aquifer system beneath a LID rain garden and traditional turf-lawn setting in San Francisco, CA.

    The data will be used to calibrate a HYDRUS-1D model to simulate recharge rates under historical and future variability of ENSO. Understanding these processes has important implications for managing groundwater resources in urban, coastal environments.

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  • Erik Landry

    Erik Landry, Washington State University
    Cover crop influences on nitrate leaching over winter

    Potato production in Skagit Valley, Washington requires the use of fertilizer inputs to be profitable. Winter rainfall may leach labile nutrients leading to environmental issues. Cover crops hold promise in their ability to decrease nutrient leaching by increasing organically bound elements.

    This research will employ 5TE soil moisture, temperature and EC sensors in conjunction with FullStop Wetting Front Detectors to measure water and solute flux for soils sown with or without winter cover crop mixtures. Our mission is to provide local organic and conventional producers with site-specific and sustainable production options. Characterizing which cover crops are best as catch crops will address grower apprehension and facilitate effective utilization.

  • Sara Baguskas

    Sara Baguskas, University of California, Santa Barbra
    Understanding processes underlying tree mortality in a Californian coastal pine forest

    Forests along the foggy coastline of California are likely to experience a warmer and possibly less foggy future.  Because summertime fog augments the water supply to forests during a time of year when conditions are otherwise warm and dry, less fog water input will likely place trees at higher risk of water stress and drought-induced mortality.

    This study seeks to understand how variation in fog-water inputs impacts the physiological state of trees in a Bishop pine (Pinus muricata D.Don) stand located on Santa Cruz Island in Channel Islands National Park.  Sara will conduct a field-based experiment where she alters plant-available soil water to these trees by manipulating fog drip to the soil surface.  The goal of this study is to better understand how fog-water inputs influence the water budget of coastal forests and thus to enhance our ability to predict how coastal forests may respond to climate change.

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  • Carrie Woods

    Carrie Woods, Clemson University
    Physiological and morphological responses of an epiphytic fern to nutrient supply

    The availability of nutrients and water can largely determine the distribution of plants.  Plants that can thrive under a variety of nutrient and water levels have higher morphological and physiological plasticity and thus a wider distribution than plants that are more specialized to particular conditions.  Pleopeltis polypodioides is an epiphytic fern (i.e., a plant that lives non-parasitically in the canopy of trees) whose distribution includes the hardwood forests of the southeastern  United States and the tropical rain forests of Central and South America.  The ability of this plant to span such a wide distribution may reside in its ability to tolerate varying levels of nutrient and water supply.

    I propose to examine the morphological and physiological characteristics of P. polypodioides to varying degrees of nutrients and moisture in both South Carolina and Costa Rica.  From previous experiments, I found that when P. polypodioides was grown in high water without added nutrients, plants showed evidence of photoinhibition resulting in lowered growth and photosynthetic rates.  When nutrients were added, there was no evidence of photoinhibition; rather, there was an increase in the photosynthetic and growth rates.

    I am proposing to test the hypothesis that in wet environments, P. plypodioides is restricted to habitats in the canopy with high nutrient content such as in canopy soil in order to mitigate the effects of photoinhibition.  I will measure morphological and physiological characteristics of P. plypodioides to varying nutrient and water supplies such as stomatal conductance, specific leaf area, and the concentration of nitrogen and phosphorus in leaf tissue.  Given that P. polypodioides can inhabit a diversity of habitats from oak trees in South Carolina to emergent canopy trees in Costa Rica suggests a potentially unique ability among ferns to tolerate a wide variety of environmental conditions.

  • Peter Bumpus

    Peter Bumpus, University of South Florida
    Assessing intermittent flow in sinkholes and recharge patterns in covered-karst terrain

    A better understanding of groundwater flow is critical for improved water resource management in complex covered-karst environments.  Flow volume through vertical sand-filled collapse columns can determine whether a wetland will drain or whether lake levels and water tables will fall, especially where aquifers are heavily pumped.  Conflict rages over the competition for water resources, thus better understanding of sinkhole behavior and effective monitoring methods of near-surface groundwater flow are extremely desirable.  It is hypothesized that self-potential measurements reflect transitions between three flow regimes: fast-flowing, deeply plugged at shallow depths that behave as though no sand column is present.

    Testing this intermittent flow hypothesis requires measuring moisture movement and matric potential changes during SP fluctuations.  An effective protocol for using hydrological sensors and SP to monitor sinkhole-associated flow will be established.  In addition, soil moisture sensors at conduits and at key hydrological, topographical, vegetative, and insolation locations will separate signals due to streaming potential from ET, root suction, and anisotropic terrain effects and confirm or deny usefulness of SP for analyzing groundwater movement.

    Understanding water movement is as important in the 21st century as finding oil was in the 20th.  It is not just a matter of protecting wetlands, lakes, and streams but managing a resource that will be used competitively for transportation (fuel cell), nourishment, and recreation.  This work also addresses locating drain fields and well fields and may help distinguish sinkholes from shrink-swell soils as subsidence sources.  This study will practically assess SP as a tool for mapping vadose zone flow.

  • Adam Howard

    Adam Howard, North Carolina State University
    Environmental and physiological responses to stress induction in two V. vinifera cultivars in North Carolina

    As North Carolina wine grape production intensifies, the importance of water management must be addressed.  Grape yield and composition, and consequently wine quality, are profoundly influenced by the water regime under which the grapes were produced.

    Despite the importance of water management, little research pertinent to this topic has been carried out in North Carolina’s primary wine grape region, the Yadkin Valley Appellation.  This region has unique soils and climate and may differ considerably from other established wine regions where water management research has been completed.  While preliminary findings suggest that precipitation amounts exceed evapotranspirative demand in this region, some water stress is desirable for quality grapes, as excess available water negatively affects grape quality.

    The primary objective of this research is to determine the status of key environmental and physiological variables at which desirable stress levels are attained in two hydraulically dissimilar v. vinifera cultivars, Grenach and Syrah.  We will exclude water from vines in these two cultivars, and use METER’s water content sensors, data loggers, and steady-state porometer to monitor soil and plant parameters as water stress is induced.  This information will assist growers in water management decisions and will be used to assess the feasibility of attaining adequate stress levels for quality grape production in this region.

  • Natalie Lounsbury

    Natalie Lounsbury, University of Maryland College Park
    Low-residue winterkilled cover crops for no-till vegetable planting

    Despite the known soil quality and environmental benefits of both cover crops and reduced tillage, integrating cover crops and eliminating tillage for the earliest spring vegetables remains problematic in the Northeast and Mid-Atlantic United States.  Many traditional, high-residue cover crops exacerbate the problem of cool, wet soils in spring and can immobilize nitrogen for the subsequent crop.  Alternative, low-residue winter killed crops have the potential to provide environmental and soil quality benefits such as nutrient capture, erosion prevention and organic matter addition while facilitating early planting in spring without necessitating tillage.

    This research will investigate the use of alternative cover crops such as forage radish, phacelia, black oats and lablab bean for no-till spring planting of vegetables.  Using METER 5TE sensors, we will monitor soil moisture and temperature to determine appropriate planting dates and we work to establish a relationship between pore water EC and nitrate concentrations to monitor the decomposition of cover crops and their ability to provide N to the subsequent crop.

  • Felipe Barrios Masias

    Honorable Mention – Felipe Barrios Masias, University of California, Davis
    Testing innovative irrigation methods to increase water use efficiency

    Alternative irrigation methods that use less water but produce high yields contribute to agricultural sustainability. This project focuses on the promising partial root drying (PRD) technique used in practice as alternate furrow irrigation to reduce water applied and increase crop water-use efficiency (yield/water applied, WUE) of processing tomatoes in California.

    Information is now available on general crop physiological responses to the PRD technique, but strategies for reliable management need to be tested for individual crops. Alternate furrow irrigation consists of selectively watering only every other furrow. Each bed receives water on just one side and alternates the sides/furrow at each irrigation. Using half of the furrows in a field can reduce the volume of water applied, potentially without a decrease in yield.

    Soil moisture and plant water status monitoring become crucial in timing each irrigation to prevent severe water stress and yield reduction but are limited by the capacity to take frequent measurements in a non-destructive fashion. Using the METER EC-5 soil moisture sensors at different growers’ fields, instant readings will be taken often enough to monitor soil water availability at two different depths. These data will be related to leaf conductance measurements from the SC-1 leaf porometer to show irrigation treatments that are water-use efficient and produce high yields. We will also analyze how soil moisture affects nitrogen leaching, canopy growth and light interception, WUE, yield, and fruit quality in every or alternate furrow irrigation regimes.