Ecology and Evolutionary Biology Commons^™

Evaluation Of Evapotranspiration Estimates Using An Existing Hybrid Machine Learning Model In A Natural And A Managed Dryland Site, Katya Esquivel Herrera

Open Access Theses & Dissertations

Evapotranspiration (ET) is a critical component of the hydrologic cycle, encompassing both evaporative water loss from surfaces and transpiration through plant stomata. The environmental factors influencing ET include water and energy availability, atmospheric capacity for water uptake, and various meteorological variables. ET serves as a unique climate variable linking water, energy, and carbon cycles. In agroecosystems, accurate ET quantification is vital for optimizing water use efficiency, irrigation management, and crop yield. Traditional methods for ET estimation involve direct measurements and indirect models, with both presenting limitations.

Recent years have witnessed the integration of remote sensing and machine learning (ML) algorithms …

Using Machine Learning And Distributed Hydrologic Modeling To Predict Soil Texture, Surface Soil Moisture And Evapotranspiration In Jornada Experimental Range, Southwestern U.S., Jorge Andres Mayo

Open Access Theses & Dissertations

In water-limited ecosystems, detailed knowledge of the soil, vegetation, and atmosphere interactions is critical to understand the processes that control the partitioning of energy, water fluxes, and biogeochemical cycles within the critical zone. This Master's thesis is divided into two main contributing sections. The first, is on the use of machine learning to reconstruct missing soil type information, and the second, on the calibration and validation of a physically-based distributed hydrological model to estimate soil moisture and evapotranspiration within the Jornada Experimental Range of the U.S. in southern New Mexico. For the first contribution, three explainable, shallow machine-learning techniques are …

Temporal Trends In Dryland Soil Carbon Fluxes In Response To Artificial And Natural Pulsed Moisture Events, Briana Alyce Salcido

Open Access Theses & Dissertations

Critical zone processes in drylands play a crucial role in the global carbon cycle, and one of the most important processes is soil CO2 efflux at the interface between soils and the atmosphere, which represents a main pathway for loss of carbon. Predicting the carbon dynamics at this interface is challenging due to the complexity of belowground processes, which include both biotic (soil respiration) and abiotic (calcite precipitation) production of CO2, as well as transport processes that include both diffusive and advective components. In this study, we aimed to investigate the contribution of soil air displacement to soil CO2 efflux …

Characterizing Spatial Variability In Soil Co2 Fluxes In The Chihuahuan Desert Using Geostatistical Techniques, Viridiana Orona

Open Access Theses & Dissertations

Spatial variability in soil CO2 efflux across landscapes is an important feature of the â??Critical Zoneâ?? within dryland ecosystems. In dryland critical zones, resources are often distributed in patches or resource islands. Although this is particularly true in natural settings, the significance of spatial variability in CO2 efflux and its patterns also extends to dryland agriculture. In both irrigated and unirrigated systems, human management practices can significantly impact both organic and inorganic carbon cycling processes, highlighting the importance of studying CO2 efflux in these systems. We examined the spatial patterns of soil CO2 efflux and quantified the magnitude and scale …

Biologically Available Phosphorus In Biocrust-Dominated Soils Of The Chihuahuan Desert, Grace Margaret Crain

Open Access Theses & Dissertations

In desert soils, phosphorus (P) is an important limiting nutrient and its cycling characteristics are less understood compared to nitrogen and carbon. Phosphorus cycling is controlled by both geochemical and biological factors. Traditionally, P availability has been characterized via sequential extraction analyses such as Hedley fractionation, but newly developed extraction methods allow for the examination of more biologically relevant P fractions, providing insight on mechanisms of P acquisition by plants and microbes. We examined these P cycling features in the context of biological soil crusts (biocrusts), which have been found to be important drivers of nutrient cycling and have the …