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Chad Higgins
Department of Biological and Ecological Engineering, College of Agricultural Science, Oregon State University, Corvallis, OR 97331, USA

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Journal article
Published: 13 April 2021 in Sustainability
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Expanding populations, the impacts of climate change, availability of arable land, and availability of water for irrigation collectively strain the agricultural system. To keep pace and adapt to these challenges, food producers may adopt unsustainable practices that may ultimately intensify the strain. What is a course of technological evolution and adoption that can break this cycle? In this paper we explore a set of technologies and food production scenarios with a new, reduced-order model. First the model is developed. The model combines limitations in the sustainable water supply, agricultural productivity as a function of intensification, and rising food demands. Model inputs are derived from the literature and historical records. Monte Carlo simulation runs of the model are used to explore the potential of existing and future technologies to bring us ever closer to a more sustainable future instead of ever farther. This is the concept of a moving sustainability horizon (the year in the future where sustainability can be achieved with current technological progress if demand remains constant). The sustainability gap is the number of years between the present and the sustainability horizon. As demand increases, the sustainability horizon moves farther into the future. As technology improves and productivity increases, the sustainability horizon is closer to the present. Sustainability, therefore, is achieved when the sustainability horizon collides with the present, closing the sustainability gap to zero. We find one pathway for water management technology adoption and innovation that closes the sustainability gap within the reduced-order model’s outputs. In this scenario, micro-irrigation adoption, minimal climate change impacts, reduced food waste, and additional transformative innovations such as smart greenhouses and agrivoltaic systems are collectively needed. The model shows that, in the absence of these changes, and continuing along our current course, the productivity of the agricultural system would become insufficient in the decade following 2050.

ACS Style

Hadi Al-Agele; Lloyd Nackley; Chad Higgins. A Pathway for Sustainable Agriculture. Sustainability 2021, 13, 4328 .

AMA Style

Hadi Al-Agele, Lloyd Nackley, Chad Higgins. A Pathway for Sustainable Agriculture. Sustainability. 2021; 13 (8):4328.

Chicago/Turabian Style

Hadi Al-Agele; Lloyd Nackley; Chad Higgins. 2021. "A Pathway for Sustainable Agriculture." Sustainability 13, no. 8: 4328.

Journal article
Published: 06 March 2021 in Sustainability
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The challenge of meeting growing food and energy demand while also mitigating climate change drives the development and adoption of renewable technologies ad approaches. Agrivoltaic systems are an approach that allows for both agricultural and electrical production on the same land area. These systems have the potential to reduced water demand and increase the overall water productivity of certain crops. We observed the microclimate and growth characteristics of Tomato plants (Solanum lycopersicon var. Legend) grown within three locations on an Agrivoltaic field (control, interrow, and below panels) and with two different irrigation treatments (full and deficit). Total crop yield was highest in the control fully irrigated areas a, b (88.42 kg/row, 68.13 kg/row), and decreased as shading increased, row full irrigated areas a, b had 53.59 kg/row, 32.76 kg/row, panel full irrigated areas a, b had (33.61 kg/row, 21.64 kg/row). Water productivity in the interrow deficit treatments was 53.98 kg/m3 greater than the control deficit, and 24.21 kg/m3 greater than the panel deficit, respectively. These results indicate the potential of Agrivoltaic systems to improve water productivity even for crops that are traditionally considered shade-intolerant.

ACS Style

Hadi Al-Agele; Kyle Proctor; Ganti Murthy; Chad Higgins. A Case Study of Tomato (Solanum lycopersicon var. Legend) Production and Water Productivity in Agrivoltaic Systems. Sustainability 2021, 13, 2850 .

AMA Style

Hadi Al-Agele, Kyle Proctor, Ganti Murthy, Chad Higgins. A Case Study of Tomato (Solanum lycopersicon var. Legend) Production and Water Productivity in Agrivoltaic Systems. Sustainability. 2021; 13 (5):2850.

Chicago/Turabian Style

Hadi Al-Agele; Kyle Proctor; Ganti Murthy; Chad Higgins. 2021. "A Case Study of Tomato (Solanum lycopersicon var. Legend) Production and Water Productivity in Agrivoltaic Systems." Sustainability 13, no. 5: 2850.

Journal article
Published: 20 January 2021 in Agriculture
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This research presents a new variable rate drip irrigation (VRDI) emitter design that can monitor individual water drops. Conventional drip systems cannot monitor the individual water flow rate per emitter. Application uniformity for conventional drip emitters can be decreased by clogged emitters, irregular emitter orifices, and decreases in pressure. A VRDI emitter can overcome the irrigation challenges in the field by increasing water application uniformity for each plant and reducing water losses. Flow rate is affected by the diameter of the delivery pipe and the pressure of the irrigation delivery system. This study compares the volumetric water flow rate for conventional drip emitters and new VRDI emitters with variable diameters inner (1 mm, 1.2 mm, 1.4 mm, and 1.6 mm) and outside (3 mm, 3.5 mm, 4 mm, and 4.5 mm) with three pressures (34 kPa, 69 kPa, and 103 kPa). The tests revealed that the new VRDI emitter had flow rates that increased as the operating pressure increased similar to a conventional drip tube. The flow rate was slightly increased in the VRDI with pressure, but even this increase did not show large changes in the flow rate. The flow rate of the conventional drip tube was 88% larger than the VRDI emitter for all pressures (p < 0.05). However, operating pressure did not affect the drop sizes at the VRDI emitter, but the generalized linear mixed models (GLM) results show that volume per drop was impacted by the outside diameter of the VRDI outlet (p < 0.05). The interaction between the inner and outside diameter was also significant at p < 0.01, and the interaction between outside diameter and pressure was statistically significant at p < 0.01. The electronic components used to control our VRDI emitter are readily compatible with off-the-shelf data telemetry solutions; thus, each emitter could be controlled remotely and relay data to a centralized data repository or decision-maker, and a plurality of these emitters could be used to enable full-field scale VRDI.

ACS Style

Hadi Al-Agele; Lloyd Nackley; Chad Higgins. Testing Novel New Drip Emitter with Variable Diameters for a Variable Rate Drip Irrigation. Agriculture 2021, 11, 87 .

AMA Style

Hadi Al-Agele, Lloyd Nackley, Chad Higgins. Testing Novel New Drip Emitter with Variable Diameters for a Variable Rate Drip Irrigation. Agriculture. 2021; 11 (2):87.

Chicago/Turabian Style

Hadi Al-Agele; Lloyd Nackley; Chad Higgins. 2021. "Testing Novel New Drip Emitter with Variable Diameters for a Variable Rate Drip Irrigation." Agriculture 11, no. 2: 87.

Journal article
Published: 25 December 2020 in Sustainability
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Agrivoltaic systems combine solar photovoltaic energy production with agriculture to improve land-use efficiency. We provide an upper-bound reduced-order cost estimate for widespread implementation of Agrivoltaic systems in the United States. We find that 20% of the US’ total electricity generation can be met with Agrivoltaic systems if less than 1% of the annual US budget is invested into rural infrastructure. Simultaneously, Agrivoltaic systems align well with existing Green New Deal goals. Widescale installation of Agrivoltaic systems can lead to a carbon dioxide (CO2) emissions reduction equivalent to removing 71,000 cars from the road annually and the creation of over 100,000 jobs in rural communities. Agrivoltaics provide a rare chance for true synergy: more food, more energy, lower water demand, lower carbon emissions, and more prosperous rural communities.

ACS Style

Kyle Proctor; Ganti Murthy; Chad Higgins. Agrivoltaics Align with Green New Deal Goals While Supporting Investment in the US’ Rural Economy. Sustainability 2020, 13, 137 .

AMA Style

Kyle Proctor, Ganti Murthy, Chad Higgins. Agrivoltaics Align with Green New Deal Goals While Supporting Investment in the US’ Rural Economy. Sustainability. 2020; 13 (1):137.

Chicago/Turabian Style

Kyle Proctor; Ganti Murthy; Chad Higgins. 2020. "Agrivoltaics Align with Green New Deal Goals While Supporting Investment in the US’ Rural Economy." Sustainability 13, no. 1: 137.

Journal article
Published: 02 October 2020 in Sustainability
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The nexus between water, energy, and food has recently evolved as a resource-management concept to deal with this intimately interwoven set of resources, their complex interactions, and the growing and continuously changing internal and external set of influencing factors, including climate change, population growth, habits and lifestyles alternations, and the dynamic prices of water, energy, and food. While an intriguing concept, the global research community is yet to identify a unifying conceptual and mathematical framework capable of adapting to integrate gathered knowledge and ensuring inclusivity by accounting for all significant interactions and feedbacks (including natural processes and anthropogenic inputs) within all nexus domains. We present an organizing roadmap for a conceptual and mathematical representation of the nexus. Our hope is that this representation will organize the nexus research and formalize a way for a generalizable framework that can be used to advance our understanding of those complex interactions, with hope that such an approach will lead to a more resilient future with sustained resources for the future generations.

ACS Style

Chad Higgins; Majdi Abou Najm. An Organizing Principle for the Water-Energy-Food Nexus. Sustainability 2020, 12, 8135 .

AMA Style

Chad Higgins, Majdi Abou Najm. An Organizing Principle for the Water-Energy-Food Nexus. Sustainability. 2020; 12 (19):8135.

Chicago/Turabian Style

Chad Higgins; Majdi Abou Najm. 2020. "An Organizing Principle for the Water-Energy-Food Nexus." Sustainability 12, no. 19: 8135.

Preprint content
Published: 23 March 2020
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Numerical weather prediction models rely heavily on boundary-layer theories, which poorly capture the interactions between the Earth’s heterogeneous surface and the internal boundary layers aloft. Further, in relation to these theories, there remains outstanding questions that still require new understanding, such as the closure of the surface energy balance, advection quantification, and surface-flux interaction. We hypothesize that under certain conditions of unstable and neutral stratification, surface thermal heterogeneities can significantly influence the flow structure and alter momentum and scalar transport. To be able to access this hypothesis, we designed the Idealized horizontal Planar Array experiment for Quantifying Surface heterogeneity (IPAQS). IPAQS took place during the summers of 2018 and 2019 at the Great Salt Lake Desert playa in western Utah at the U.S. Army Dugway Proving Ground’s Surface Layer Turbulence and Environmental Test (SLTEST) facility. The site is characterized by a long uninterrupted fetch with uniform surface roughness and large thermal and moisture heterogeneities covering a wide range of scales. Observations were made with an array of 2-m high, temporally-synchronized, fast-response sonic anemometers, and finewire thermocouples, which were deployed on a coarse grid covering an area of 800 m x 800 m with 200-m spacing. Results provide valuable insight into the spatial and temporal evolution of the flow. Fine-scale turbulence was measured using Nano-Scale Thermal Anemometry Probes (NSTAP). Meanwhile, larger-scale turbulence was captured with Doppler wind LiDARs. Presented is an overview of the experiment and initial results.

ACS Style

Travis Morrison; Marc Calaf; Eric Pardyjak; Marcus Hultmark; Chad Higgins; Giacomo Iungo; Stephan Drake; Sebastian Hoch; Dragan Zajic; Alexei Perelet; Alex Bingham; Claudia Brunner; Thomas Debell; Nipun Gunawardena; Yi-Chun Huang; Gabe Mogollon; Behzad Najafi; Yajat Pandya; Matteo Puccioni; Dhiraj Kumar Singh Sr. An atmospheric surface layer study: The Idealized horizontal Planar Array experiment for Quantifying Surface Heterogeneity (IPAQS). 2020, 1 .

AMA Style

Travis Morrison, Marc Calaf, Eric Pardyjak, Marcus Hultmark, Chad Higgins, Giacomo Iungo, Stephan Drake, Sebastian Hoch, Dragan Zajic, Alexei Perelet, Alex Bingham, Claudia Brunner, Thomas Debell, Nipun Gunawardena, Yi-Chun Huang, Gabe Mogollon, Behzad Najafi, Yajat Pandya, Matteo Puccioni, Dhiraj Kumar Singh Sr. An atmospheric surface layer study: The Idealized horizontal Planar Array experiment for Quantifying Surface Heterogeneity (IPAQS). . 2020; ():1.

Chicago/Turabian Style

Travis Morrison; Marc Calaf; Eric Pardyjak; Marcus Hultmark; Chad Higgins; Giacomo Iungo; Stephan Drake; Sebastian Hoch; Dragan Zajic; Alexei Perelet; Alex Bingham; Claudia Brunner; Thomas Debell; Nipun Gunawardena; Yi-Chun Huang; Gabe Mogollon; Behzad Najafi; Yajat Pandya; Matteo Puccioni; Dhiraj Kumar Singh Sr. 2020. "An atmospheric surface layer study: The Idealized horizontal Planar Array experiment for Quantifying Surface Heterogeneity (IPAQS)." , no. : 1.

Journal article
Published: 07 August 2019 in Scientific Reports
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Solar energy has the potential to offset a significant fraction of non-renewable electricity demands globally, yet it may occupy extensive areas when deployed at this level. There is growing concern that large renewable energy installations will displace other land uses. Where should future solar power installations be placed to achieve the highest energy production and best use the limited land resource? The premise of this work is that the solar panel efficiency is a function of the location’s microclimate within which it is immersed. Current studies largely ignore many of the environmental factors that influence Photovoltaic (PV) panel function. A model for solar panel efficiency that incorporates the influence of the panel’s microclimate was derived from first principles and validated with field observations. Results confirm that the PV panel efficiency is influenced by the insolation, air temperature, wind speed and relative humidity. The model was applied globally using bias-corrected reanalysis datasets to map solar panel efficiency and the potential for solar power production given local conditions. Solar power production potential was classified based on local land cover classification, with croplands having the greatest median solar potential of approximately 28 W/m2. The potential for dual-use, agrivoltaic systems may alleviate land competition or other spatial constraints for solar power development, creating a significant opportunity for future energy sustainability. Global energy demand would be offset by solar production if even less than 1% of cropland were converted to an agrivoltaic system.

ACS Style

Elnaz H. Adeh; Stephen P. Good; M. Calaf; Chad W. Higgins. Solar PV Power Potential is Greatest Over Croplands. Scientific Reports 2019, 9, 1 -6.

AMA Style

Elnaz H. Adeh, Stephen P. Good, M. Calaf, Chad W. Higgins. Solar PV Power Potential is Greatest Over Croplands. Scientific Reports. 2019; 9 (1):1-6.

Chicago/Turabian Style

Elnaz H. Adeh; Stephen P. Good; M. Calaf; Chad W. Higgins. 2019. "Solar PV Power Potential is Greatest Over Croplands." Scientific Reports 9, no. 1: 1-6.

Proceedings article
Published: 01 January 2018
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ACS Style

Holly Jayne Oldroyd; Eric R. Pardyjak; Chad W. Higgins; Marc B. Parlange. LAND-ATMOSPHERE COUPLING MECHANISMS OVER STEEP TERRAIN: TURBULENT TRANSPORT AND MODELING CHALLENGES. 2018, 1 .

AMA Style

Holly Jayne Oldroyd, Eric R. Pardyjak, Chad W. Higgins, Marc B. Parlange. LAND-ATMOSPHERE COUPLING MECHANISMS OVER STEEP TERRAIN: TURBULENT TRANSPORT AND MODELING CHALLENGES. . 2018; ():1.

Chicago/Turabian Style

Holly Jayne Oldroyd; Eric R. Pardyjak; Chad W. Higgins; Marc B. Parlange. 2018. "LAND-ATMOSPHERE COUPLING MECHANISMS OVER STEEP TERRAIN: TURBULENT TRANSPORT AND MODELING CHALLENGES." , no. : 1.

Journal article
Published: 28 June 2013 in Geophysical Research Letters
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ACS Style

Chad W. Higgins; Gabriel G. Katul; Martin Froidevaux; Valentin Simeonov; Marc B. Parlange. Are atmospheric surface layer flows ergodic? Geophysical Research Letters 2013, 40, 3342 -3346.

AMA Style

Chad W. Higgins, Gabriel G. Katul, Martin Froidevaux, Valentin Simeonov, Marc B. Parlange. Are atmospheric surface layer flows ergodic? Geophysical Research Letters. 2013; 40 (12):3342-3346.

Chicago/Turabian Style

Chad W. Higgins; Gabriel G. Katul; Martin Froidevaux; Valentin Simeonov; Marc B. Parlange. 2013. "Are atmospheric surface layer flows ergodic?" Geophysical Research Letters 40, no. 12: 3342-3346.

Journal article
Published: 06 October 2012 in Geophysical Research Letters
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[1] The residual of the surface energy budget is represented as the linearized sum of energy losses due to storage, advection and flux underestimation. Individual contributions to the residual can be quantified through constrained multiple linear regression which identifies the site specific processes that are responsible for the lack of energy budget closure. This residual decomposition approach is applied to energy balance data from the Surface Layer Turbulence and Environmental Science Test (SLTEST) site at the Dugway Proving Grounds in the Utah Salt Flats. In this case, energy storage in the soil and underestimation of the soil heat flux accounted for 89% of the residual variance. Underestimation of the sensible and latent heat fluxes had no apparent contribution to the residual, and the contribution of advection to the residual was not statistically significant.

ACS Style

Chad W. Higgins. A-posteriori analysis of surface energy budget closure to determine missed energy pathways. Geophysical Research Letters 2012, 39, 1 .

AMA Style

Chad W. Higgins. A-posteriori analysis of surface energy budget closure to determine missed energy pathways. Geophysical Research Letters. 2012; 39 (19):1.

Chicago/Turabian Style

Chad W. Higgins. 2012. "A-posteriori analysis of surface energy budget closure to determine missed energy pathways." Geophysical Research Letters 39, no. 19: 1.

Journal article
Published: 10 February 2012 in Boundary-Layer Meteorology
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Taylor’s frozen turbulence hypothesis is the central assumption invoked in most experiments designed to investigate turbulence physics with time resolving sensors. It is also frequently used in theoretical discussions when linking Lagrangian to Eulerian flow formalisms. In this work we seek to quantify the effectiveness of Taylor’s hypothesis on the field scale using water vapour as a passive tracer. A horizontally orientated Raman lidar is used to capture the humidity field in space and time above an agricultural region in Switzerland. High resolution wind speed and direction measurements are conducted simultaneously allowing for a direct test of Taylor’s hypothesis at the field scale. Through a wavelet decomposition of the lidar humidity measurements we show that the scale of turbulent motions has a strong influence on the applicability of Taylor’s hypothesis. This dependency on scale is explained through the use of dimensional analysis. We identify a ‘persistency scale’ that can be used to quantify the effectiveness of Taylor’s hypothesis, and present the accuracy of the hypothesis as a function of this non-dimensional length scale. These results are further investigated and verified through the use of large-eddy simulations.

ACS Style

Chad W. Higgins; Martin Froidevaux; Valentin Simeonov; Nikki Vercauteren; Caitlin Barry; Marc Parlange. The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer. Boundary-Layer Meteorology 2012, 143, 379 -391.

AMA Style

Chad W. Higgins, Martin Froidevaux, Valentin Simeonov, Nikki Vercauteren, Caitlin Barry, Marc Parlange. The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer. Boundary-Layer Meteorology. 2012; 143 (2):379-391.

Chicago/Turabian Style

Chad W. Higgins; Martin Froidevaux; Valentin Simeonov; Nikki Vercauteren; Caitlin Barry; Marc Parlange. 2012. "The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer." Boundary-Layer Meteorology 143, no. 2: 379-391.

Journal article
Published: 25 August 2009 in Water Resources Research
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ACS Style

Hendrik Huwald; Marc-Olivier Boldi; Marc B. Parlange; Elie Bou-Zeid; Chad W. Higgins; Michael Lehning. Albedo effect on radiative errors in air temperature measurements. Water Resources Research 2009, 45, 1 .

AMA Style

Hendrik Huwald, Marc-Olivier Boldi, Marc B. Parlange, Elie Bou-Zeid, Chad W. Higgins, Michael Lehning. Albedo effect on radiative errors in air temperature measurements. Water Resources Research. 2009; 45 (8):1.

Chicago/Turabian Style

Hendrik Huwald; Marc-Olivier Boldi; Marc B. Parlange; Elie Bou-Zeid; Chad W. Higgins; Michael Lehning. 2009. "Albedo effect on radiative errors in air temperature measurements." Water Resources Research 45, no. 8: 1.

Journal article
Published: 01 October 2003 in Boundary-Layer Meteorology
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Field experimental data in the atmospheric surface layer are analyzed using toolsfrom statistical geometry. The data consist of velocity measurements from sonicanemometer arrays. In the context of large eddy simulations (LES), these arrayspermit the spatial filtering needed to separate large from small scales. Time seriesof various quantities relevant to LES are evaluated from the data. Results show thatthe preferred filtered fluid deformation is axisymmetric extension and the preferredsubgrid stress state is axisymmetric contraction. The filtered fluctuating vorticityshows preferred alignments with the mean vorticity, with the streamwise direction,and with the intermediate strain-rate eigenvector. The alignment between eigenvectorsof the subgrid-scale stress and filtered strain rate is used to test eddy viscosity andmixed model formulations. In qualitative agreement with prior laboratory measurements at much lower Reynolds numbers, a bimodal distribution is observed, which can be reduced to good alignment with eddy viscosity closure using the mixed model.

ACS Style

Chad W. Higgins; Marc B. Parlange; C. Meneveau. Alignment Trends of Velocity Gradients and Subgrid-Scale Fluxes in the Turbulent Atmospheric Boundary Layer. Boundary-Layer Meteorology 2003, 109, 59 -83.

AMA Style

Chad W. Higgins, Marc B. Parlange, C. Meneveau. Alignment Trends of Velocity Gradients and Subgrid-Scale Fluxes in the Turbulent Atmospheric Boundary Layer. Boundary-Layer Meteorology. 2003; 109 (1):59-83.

Chicago/Turabian Style

Chad W. Higgins; Marc B. Parlange; C. Meneveau. 2003. "Alignment Trends of Velocity Gradients and Subgrid-Scale Fluxes in the Turbulent Atmospheric Boundary Layer." Boundary-Layer Meteorology 109, no. 1: 59-83.