- Christopher Beltz
Christopher Beltz – University of Wyoming
The effects of environmental change on carbon cycling across the semi-arid west
Increased availability of nitrogen (N) has the potential to alter many ecosystem functions—and is doing so already. This is largely due to the widespread response of net primary productivity (NPP) and soil respiration to N. Anthropogenic fixation of N has increased inputs into the biosphere from 0.5 kg N ha-1 yr-1 to upwards of 10 kg N ha-1 yr-1. Within semi-arid environments, the relationships between available N and ecosystem processes are especially complex due to strong limitation by low—and highly variable—precipitation. This causes temporally complex co-limitation by water and N. In addition, temperature is known to have significant effects on soil respiration. Given the IPCC projections, in which both N and precipitation are altered, the current development of energy resources in the western US provides an opportunity to ask basic and applied research questions related to the effects of increased nitrogen and water availability on carbon cycling. To better understand these effects, I will examine the interactive effects of nitrogen and water application on the carbon cycle and assess the relative effects of plant and microbial communities on carbon cycling and the carbon budget. METER meteorological stations will allow me to monitor site conditions (i.e., precipitation, air temperature, soil moisture, and soil temperature) with high temporal resolution, increasing the realm of inference of this study.
- Daniel Adamson
Daniel Adamson – University of Wyoming
Degradation of soil-applied herbicides under limited irrigation
Soil-applied herbicides are important for controlling weeds in many crops, as they offer a broadened control spectrum and chemical diversity, especially when fewer POST-applied herbicides are available. However, if soil-applied herbicides persist in the soil too long, there is risk for damage to susceptible rotational crops in succeeding years. As herbicide degradation in the soil is highly dependent on water, imminent needs to reduce agricultural water use in the future could lead to limited herbicide degradation and a greater risk for carryover. This project seeks to understand how limited irrigation affects the efficacy and carryover of soil-applied herbicides in Wyoming’s irrigated crop rotations. A two-part field study is currently being undertaken by applying four soil-applied herbicides to dry beans and four soil-applied herbicides to corn. In 2015, three irrigation treatments (100%, 80%, 69% of crop evapotranspiration) were applied to both crops, and soil moisture was monitored using ten METER Em50 data loggers each with four GS-1 soil moisture sensors. Volumetric soil water content of the three irrigation treatments averaged 22%, 18%, and 17% throughout the growing season. Crop yield decreased as irrigation was reduced. Soil samples collected at regular intervals following herbicide application will be analyzed in 2016 for herbicide level and used to perform a greenhouse bioassay to determine crop response to residual herbicide. Crop response will also be evaluated in the field during the second year when sugar beet, sunflower, and dry bean or corn will be planted over the original plots and assessed for herbicide damage.
- David Sullivan
David Sullivan – Washington State University
Strip tillage and cover cropping for enhanced water use efficiency in western Washington organic vegetable farms
Growing soil health and water use concerns in conventional tillage systems have led to increased interest in reduced tillage practices due to enhanced soil quality, moisture retention, and decreased erosion. A balanced approach utilizing strip tillage and high-residue cover crops has the potential to reduce these negative effects while protecting soil health and conserving water. High residue vegetative mulches created by spring-terminated cover crops have been shown to suppress weeds in organic systems as well as increase soil moisture when compared to conventional tillage systems. This project will investigate how these high-residue cover crop based strip till systems can improve water use efficiency by investigating water dynamics of the flailed mulch layer in comparison to bare ground systems.
A fall-planted cereal rye cover crop terminated during mid-anthesis via flail mowing will be subjected to strip tillage or full tillage prior to transplanting squash. Separate drip irrigation application schedules will be maintained per treatment utilizing the WSU AgWeathernet irrigation scheduler platform, paired with METER 5TM volumetric moisture sensors and monitored in real time with Em50G wireless loggers. Temperature and moisture data will be taken at two soil depths and two locations across the bed. Upon completion, this project will help address the nexus of food, energy, and water with the potential to increase farming system resiliency to climate change by conserving water resources in Washington state.
- Elise Connor
Elise Connor – University of Texas at Austin
Rethinking measurements of plant water status in response to drought
Drought is a primary factor limiting plant productivity, adversely affecting plants from the molecular to the physiological level. Many studies have examined the effects of drought, but few include the effects of fungal symbionts. Yet endophytic fungi that colonize leaves can improve plant drought tolerance by an order of magnitude or more. For instance, fungal endophytes can reduce plant water loss by closing plant stomates and prevent cellular desiccation by accumulating solutes in plant cells. In some cases, the presence of a fungal endophyte completely negates the effects of drought on plant growth and transpiration efficiency. As such, fungal symbionts may lead researchers to incorrectly identify mechanisms of drought tolerance within plants. Furthermore, fungal effects may explain why current conductance models have been unable to predict observed stomatal responses to water stress. Therefore, to better understand plant drought dynamics, I propose to use METER’s SC-1 Leaf Porometer to partition the effects of soil moisture and endophytes on plant stomatal conductance.
- Elizabeth Ernst
Elizabeth Ernst – Michigan Technological University
Understanding soil conditions in Boreal-Taiga ecosystems and how they influence wildfire extent, severity, and distribution
The Arctic-boreal region is experiencing a significant change in climate, trending toward warmer, longer summers. These increased temperatures are expected to dry fuels, causing them to become more susceptible to ignite and burn during extended wildfire seasons. Wildland fires are the number one disturbance in Canada’s Northwest Territories (NWT), and permafrost thaw is the second largest disturbance factor. It is important to understand the relationship between these two disturbances, as they drive and influence each other in a positive feedback loop. These processes are driven by several factors, including weather and climate, topography, and soil composition. In order to understand how the effects of wildfires vary across different ecological zones and permafrost conditions, preseason soil and fuel moisture patterns are being studied both on the ground and with remote sensing technology. Long-term trends in soil moisture patterns leading up to the 2014 fire season near Yellowknife, NWT, will be compared to field measurements taken during summer 2016. METER’s 5TM sensors and Procheck hand-held devices will be used to measure soil conditions, including moisture and organic matter; the SATURO will test the field-saturated hydraulic conductivity to estimate how much water is available for runoff and the regeneration of vegetation. Measurements will be taken at a variety of post-fire conditions (unburned to high burn severity) and permafrost interactions (continuous, discontinuous, and sporadic). These results will contribute to an ongoing effort of understanding the vulnerability of Boreal-Taiga ecosystems to increasing wildfire activity in a changing climate.
- Jessica Stevens
Jessica Stevens – University of Tennessee Knoxville
Corpse decomposition hot spots: monitoring changes in grave soils
Corpse or carcass decomposition has garnered interest from both forensic and ecological perspectives. Our research focuses on the microbial ecology of terrestrial vertebrate mortality decomposition events, with an emphasis on changes in soil biology and chemistry. We plan to use METER soil moisture sensors to predict both soil moisture and fat/lipid content in these decomposition soils in lab and field experiments. This will provide new knowledge about these sensors and their potential applications in forensic science.
- Leander Anderegg
Leander Anderegg – University of Washington
The search for CO2 fertilization
Trees are merchants; they sell water to the atmosphere in exchange for the CO2 they need to photosynthesize sugars. The exchange rate, or ‘water-use efficiency’ that drives the plant carbon-water marketplace is a function of atmospheric CO2 concentrations. Thus, theoretically human carbon emissions, which have increased atmospheric CO2 by 40% since 1850, should increase plant water use efficiency, resulting in “CO2 fertilization” of our forests and crops. However, evidence for CO2 fertilization is extremely mixed. I seek to understand when, where, and why trees experience CO2 fertilization by using METER equipment to quantify the environmental constraints (e.g., the availability of water, light, temperature, relative humidity) experienced by two tree species, Abies lasiocarpa and Populus tremuloides, across their elevation ranges in southwest Colorado. By combining these environmental data with existing tree growth and water-use efficiency records from tree cores, I will use a parameterized forest growth model (3-PG) to determine how environmental constraints determine whether and how much trees benefit from increasing carbon dioxide concentrations.
- Rebecca Sheridan
Rebecca Sheridan – University of Idaho
Hydraulic physiology of planted douglas-fir seedlings in response to water-limiting conditions
This project will measure the hydraulic conductivity of Douglas-fir seedlings, and determine how seedling hydraulic conductivity changes in limiting soil water conditions. Hundreds of thousands of Douglas-fir seedlings are planted each year in the state of Idaho, and are subjected to a wide variety of environmental conditions. Field observations show that planted Douglas-fir seedlings are not surviving; limited soil moisture at the planting sites is one suspected cause of seedling death. The project will address a forestry problem, the failure of planted seedlings to survive, with the tools and mechanisms from the discipline of plant hydraulic physiology, including a high-pressure flow meter, a Sperry apparatus, and METER instruments. We will measure morphological and physiological characteristics of the seedlings before and after planting. Control seedlings will be well-watered throughout the experiment, and treatment seedlings will experience moderate or extreme drought conditions. The results will be analyzed using analysis of variance. The results will elucidate how the hydraulic physiology of the seedlings responds planting, which will help improve survival of seedlings and ensure reforestation and restoration goals are met.
- Thomas Green
Thomas Green – Michigan State University
Effects of gravel layer particle size and sub-grade slope on the magnitude of spatial pattern of soil water in a variable-depth USGA-specification putting green
Uniform distribution of soil water in high-sand content putting greens is a major concern for golf course superintendents. Although gravel is commonly used as a component of a sand-based root zone in order to increase moisture retention, the contour and slope in putting greens significantly affect moisture retention due to gravity. As a result, coarse-textured soils become prematurely dry in higher elevations, and excessively wet in lower elevations. This non-uniform wetting of soil not only could hamper putting green performance, but also, could increase water and labor inputs. The objective of this study is to assess the impact of gravel layer particle size and slope on soil water content in a variable-depth (shallower at the slope apex, yet deeper at the slope base) high-sand content root zone. Due to lack of published research and the United States Golf Association’s (USGA) wide-ranged specification for selection of a gravel based on the root zone material, determining the optimal bridging, filtering, permeability, and uniformity factors capable of increasing root zone soil moisture uniformity across the undulations of a variable-depth, high-sand content putting green is critical. Our objective is to evaluate the effects of gravel layer particle size and sub-grade slope on the magnitude and spatial pattern of soil water in a variable-depth, USGA-specification putting green. Our hypothesis is the following: increasing the particle size difference between the gravel and root zone layers, in combination with a variable-depth root zone, will improve soil moisture uniformity in an undulating putting green.