Open Access Publications

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Open access publications by faculty, postdocs, and graduate students in the Department of Geography and Spatial Sciences.

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A global open-source dataset of monthly irrigated and rainfed cropped areas (MIRCA-OS) for the 21st century
(Scientific Data, 2025-02-04) Kebede, Endalkachew Abebe; Oluoch, Kevin Ong’are; Siebert, Stefan; Mehta, Piyush; Hartman, Sarah; Jägermeyr, Jonas; Ray, Deepak; Ali, Tariq; Brauman, Kate A.; Deng, Qinyu; Xie, Wei; Davis, Kyle Frankel
Crop production is among the most extensive human activities on the planet – with critical importance for global food security, land use, environmental burden, and climate. Yet despite the key role that croplands play in global land use and Earth systems, there remains little understanding of how spatial patterns of global crop cultivation have recently evolved and which crops have contributed most to these changes. Here we construct a new data library of subnational crop-specific irrigated and rainfed harvested area statistics and combine it with global gridded land cover products to develop a global gridded (5-arcminute) irrigated and rainfed cropped area (MIRCA-OS) dataset for the years 2000 to 2015 for 23 crop classes. These global data products support critical insights into the spatially detailed patterns of irrigated and rainfed cropland change since the start of the century and provide an improved foundation for a wide array of global assessments spanning agriculture, water resource management, land use change, climate impact, and sustainable development.
Swapping rice for alternative cereals can reduce climate-induced production losses and increase farmer incomes in India
(Nature Communications, 2025-03-02) Wei, Dongyang; Castro, Leslie Guadalupe; Chhatre, Ashwini; Tuninetti, Marta; Davis, Kyle Frankel
The rising homogeneity of global crop supply has increased vulnerability to climatic and economic disruptions. While substantial work has examined yield variations in relation to climate variability, little is known about the influence of harvested area on production stability. To investigate this, here we take the example of monsoon cereal production in India, which has steadily shifted towards climate-sensitive rice and away from alternative cereals (finger millet, maize, pearl millet, and sorghum). We find that variations in harvested area are significantly associated with current and past price fluctuations for all cereals except rice. This suggests that farmer decisions based on economic factors may exercise great influence in determining variations in harvested area. We also show that optimized allocations of harvested area can reduce climate-induced production loss by 11% or improve farmer net profit by 11% while maintaining calorie production and cropland area. Such improvements would be possible by reducing harvested areas dedicated to rice and increasing areas allocated to alternative cereals. Our findings show that strategies using harvested area to address cereal yield fluctuations and improve farm profits could complement ongoing efforts to improve alternative cereal yields and stabilize cereal production.
Deepening water scarcity in breadbasket nations
(Nature Communications, 2025-01-28) Deng, Qinyu; Sharretts, Tyler; Ali, Tariq; Ao, Yufei Zoe; Chiarelli, Davide Danilo; Demeke, Betelhem; Marston, Landon; Mehta, Piyush; Mekonnen, Mesfin; Rulli, Maria Cristina; Tuninetti, Marta; Xie, Wei; Davis, Kyle Frankel
Water is crucial for meeting sustainability targets, but its unsustainable use threatens human wellbeing and the environment. Past assessments of water scarcity (i.e., water demand in exceedance of availability) have often been spatially coarse and temporally limited, reducing their utility for targeting interventions. Here we perform a detailed monthly sub-basin assessment of the evolution of blue (i.e., surface and ground) water scarcity (years 1980-2015) for the world’s three most populous countries – China, India, and the USA. Disaggregating by specific crops and sectors, we find that blue water demand rose by 60% (China), 71% (India), and 27% (USA), dominated by irrigation for a few key crops (alfalfa, maize, rice, wheat). We also find that unsustainable demand during peak months of use has increased by 101% (China), 82% (India), and 49% (USA) and that 32% (China), 61% (India), and 27% (US) of sub-basins experience at least 4 months of scarcity. These findings demonstrate that rising water demands are disproportionately being met by water resources in already stressed regions and provide a basis for targeting potential solutions that better balance the water needs of humanity and nature.
Embodied Belonging in the Social Science Lab
(ACME: An International Journal for Critical Geographies, 2025-01-13) Embodiment Lab; Abou Ali, Hanan; Bryan, James Edward; Chennault, Carrie; Grover, Dharni; Haghdadi, Mehrnaz; Islam, Faisal Bin; Kim, Nari; Lucas, Nora; Mohana, Nusrat T.; Naylor, Lindsay; Nixon, Rebecca; Obringer, Kelsey M.; Ramsay, Georgina; Sultana, Naznin Nahar; Thakkar, Kaanan; Thayer, Nathan
The Embodiment Lab, rooted in critical human geography, is grounded in embodiment, belonging, mentorship, care, and temporal dynamics to challenge norms in the neoliberal university. We argue that the Lab serves as a counter-practice within the academy by prioritizing our individual and collective well-being over productivity metrics. Weekly practices cultivate radical vulnerability, creating a foundation for a caring environment. Delving into multifaceted spatial dimensions our experiences suggest that the Lab becomes a living example of a feminist ethic of care. Belonging emerges as an antidote to the exclusions ingrained in academic spaces. The Lab empowers its scholars to challenge uneven power dynamics, fostering inclusion where diverse voices are heard. The Lab's emphasis on collective action and intentional processes of growth contrasts with a conventional fast, metric-driven tempo. In this paper, we offer a model to center care in lab spaces by reflecting on our own experiences in a space that values scholars as whole individuals rather than vessels of productivity. We illustrate the reflexive character of the Lab, acknowledging its adaptability and dynamism over time. Rejecting the neoliberal norms that too often dictate research spaces, the Lab exemplifies the messy and ongoing process of creating care-full academic spaces.
Cropland expansion links climate extremes and diets in Nigeria
(Science Advances, 2025-01-10) Khan, Bhoktear; Mehta, Piyush; Wei, Dongyang; Ali, Hanan Abou; Adeluyi, Oluseun; Alabi, Tunrayo; Olayide, Olawale; Uponi, John; Davis, Kyle Frankel
Climate change threatens smallholder agriculture and food security in the Global South. While cropland expansion is often used to counter adverse climate effects despite ecological trade-offs, the benefits for diets and nutrition remain unclear. This study quantitatively examines relationships between climate anomalies, forest loss from cropland expansion, and dietary outcomes in Nigeria, Africa’s most populous country. Combining high-resolution data on forest cover and climate variables within random forest and panel regression models, we find that 25 to 31% of annual forest loss is linked to climate variability. Using georeferenced household survey data, we then find that changes in forest cover have a significant positive association with changes in child diet diversity—a key proxy of nutritional adequacy—while cropland expansion does not, suggesting that such forest conversions may be an ineffective climate adaptation strategy for improving nutrition. Our findings highlight the potential of nutrition-sensitive climate adaptation to enhance yields, promote nutritious cropping choices, and protect remaining forests.
Improving future agricultural sustainability by optimizing crop distributions in China
(PNAS Nexus, 2025-01-07) Guan, Qi; Tang, Jing; Davis, Kyle Frankel; Kong, Mengxiang; Feng, Lian; Shi, Kun; Schurgers, Guy
Improving agricultural sustainability is a global challenge, particularly for China's high-input and low-efficiency cropping systems with environmental tradeoffs. Although national strategies have been implemented to achieve Sustainable Development Goals in agriculture, the potential contributions of crop switching as a promising solution under varying future climate change are still under-explored. Here, we optimize cropping patterns spatially with the targets of enhancing agriculture production, reducing environmental burdens, and achieving sustainable fertilization across different climate scenarios. Compared with current cropping patterns, the optimal crop distributions under different climate scenarios consistently suggest allocating the planting areas of maize and rapeseed to the other crops (rice, wheat, soybean, peanut, and potato). Such crop switching can consequently increase crop production by 14.1%, with accompanying reductions in environmental impacts (8.2% for leached nitrogen and 24.0% for irrigation water use) across three representative Shared Socio-economic Pathways from 2020 to 2100. The sustainable fertilization rates vary from 148–173 kg N ha−1 in 2030 to 213–253 kg N ha−1 in 2070, significantly smaller than the current rate (305 kg N ha−1). These outcomes highlight large potential benefits of crop switching and fertilizer management for improving China's future agricultural sustainability.
Advances on the Global Human Settlement Layer by joint assessment of Earth Observation and population survey data
(International Journal of Digital Earth, 2024-08-30) Pesaresi, Martino; Schiavina, Marcello; Politis, Panagiotis; Freire, Sergio; Krasnodębska, Katarzyna; Uhl, Johannes H.; Carioli, Alessandra; Corbane, Christina; Dijkstra, Lewis; Florio, Pietro; Friedrich, Hannah K.; Gao, Jing; Leyk, Stefan; Lu, Linlin; Maffenini, Luca; Mari-Rivero, Ines; Melchiorri, Michele; Syrris, Vasileios; Van Den Hoek, Jamon; Kemper, Thomas
The Global Human Settlement Layer (GHSL) project fosters an enhanced, public understanding of the human presence on Earth. A decade after its inception in the Digital Earth 2020 vision, GHSL is an established project of the European Commission’s Joint Research Centre and an integral part of the Copernicus Emergency Management Service. The 2023 GHSL edition, a result of rigorous research on Earth Observation data and population censuses, contributes significantly to understanding worldwide human settlements. It introduces new elements like 10-m-resolution, sub-pixel estimation of built-up surfaces, global building height and volume estimates, and a classification of residential and non-residential areas, improving population density grids. This paper evaluates the key components of the GHSL, including the Symbolic Machine Learning approach, using novel reference data. These data enable a comparative assessment of GHSL model predictions on the evolution of built-up surface, building heights, and resident population. Empirical evidence suggests that GHSL estimates are the most accurate in the public domain today, e.g. achieving an IoU of 0.98 for the water class, 0.92 for the built-up class, and 0.8 for the non-residential class at 10 m resolution. At 100 m resolution, we find that the MAE of built-up surface estimates corresponds to 6% of the grid cell area, the MAE for the building height estimates is 2.27 m, and we find a total allocation accuracy of 83% for resident population. This paper consolidates the theoretical foundation of the GHSL and highlights its innovative features for transparent Artificial Intelligence, facilitating international decision-making processes.
High-Resolution Modeling and Projecting Local Dynamics of Differential Vulnerability to Urban Heat Stress
(Earth's Future, 2024-10-06) Marginean, I.; Cuaresma, J. Crespo; Hoffmann, R.; Muttarak, R.; Gao, J.; Daloz, Anne Sophie
Climate change-induced heat stress has significant effects on human health, and is influenced by a wide variety of factors. Most assessments of future heat-related risks however are based on coarse resolution projections of heat hazards and overlook the contribution of relevant factors other than climate change to the negative impacts on health. Research highlights sociodemographic disparities related to heat stress vulnerability, especially among older adults, women and individuals with low socioeconomic status, leading to higher morbidity and mortality rates. There is thus an urgent need for detailed, local information on demographic characteristics underlying vulnerability with refined spatial resolution. This study aims to address the research gaps by presenting a new population projection exercise at high-resolution based on the Bayesian modeling framework for the case study of Madrid, using demographic data under the scenarios compatible with the Shared Socioeconomic Pathways. We examine the spatial and temporal distribution of population subgroups at the intra-urban level within Madrid. Our findings reveal a concentration of vulnerable populations, as measured by their age, sex and educational attainment level in some of the city's most disadvantaged neighborhoods. These vulnerable clusters are projected to widen in the future unless a sustainable trajectory is realized, driving vulnerability dynamics toward a more uniform and resilient change. These results can guide local adaptation efforts and support climate justice initiatives to protect vulnerable communities in urban environments. Key Points - Population projections by age, sex and education at small-area levels allow for high-resolution heat vulnerability modeling - Vulnerability to heat stress can vary widely between different areas in a city, and even within a single neighborhood - Areas that are vulnerable today are projected to become even more vulnerable in all Shared Socioeconomic Pathway scenarios except for that assuming a sustainable development narrative Plain Language Summary Heat stress is a major risk factor for human health, especially in cities where more people are exposed to increasingly higher temperatures in summer. Cities are usually hotter than their surrounding rural areas due to the predominance of dark, impervious surfaces which absorb more heat. Assessing heat risks for public health requires measurements of the hazard, such as a prolonged period with high temperatures, the population exposed to the hazard and characteristics of populations that make them more vulnerable to heat related diseases or even death. Various approaches and tools for risk assessment have been developed, but most of them focus on the hazard and exposure components. In this paper, we measure and project vulnerability to heat stress in alternative scenarios, using different population characteristics, such as age, sex and education. Our results show that there are compelling differences between areas within the city of Madrid and that areas that are vulnerable today will become even more vulnerable unless we follow a path of sustainable development. Detailed assessments of the spatial distribution of vulnerability within a city are relevant for developing adaptation solutions that target vulnerable populations and are thus more effective in reducing heat-related risks.
El Niño and positive Indian Ocean Dipole conditions simultaneously reduce the production of multiple cereals across India
(Environmental Research Letters, 2024-09-09) Gurazada, Madhulika; McDermid, Sonali; DeFries, Ruth; Davis, Kyle F.; Singh, Jitendra; Singh, Deepti
Natural climate phenomena like El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) influence the Indian monsoon and thereby the region's agricultural systems. Understanding their influence can provide seasonal predictability of agricultural production metrics to inform decision-making and mitigate potential food security challenges. Here, we analyze the effects of ENSO and IOD on four agricultural production metrics (production, harvested area, irrigated area, and yields) for rice, maize, sorghum, pearl millet, and finger millet across India from 1968 to 2015. El Niños and positive-IODs are associated with simultaneous reductions in the production and yields of multiple crops. Impacts vary considerably by crop and geography. Maize and pearl millet experience large declines in both production and yields when compared to other grains in districts located in the northwest and southern peninsular regions. Associated with warmer and drier conditions during El Niño, >70% of all crop districts experience lower production and yields. Impacts of positive-IODs exhibit relatively more spatial variability. La Niña and negative-IODs are associated with simultaneous increases in all production metrics across the crops, particularly benefiting traditional grains. Variations in impacts of ENSO and IOD on different cereals depend on where they are grown and differences in their sensitivity to climate conditions. We compare production metrics for each crop relative to rice in overlapping rainfed districts to isolate the influence of climate conditions. Maize production and yields experience larger reductions relative to rice, while pearl millet production and yields also experience reductions relative to rice during El Niños and positive-IODs. However, sorghum experiences enhanced production and harvested areas, and finger millet experiences enhanced production and yields. These findings suggest that transitioning from maize and rice to these traditional cereals could lower interannual production variability associated with natural climate variations.
Water-Energy-Food (WEF) Nexus and the SDGs in Central and South Asia
(Springer, Cham, 2024-08-04) Akram, Humayoun Akram; Mohazzam, Sardar; Ali, Saleem H.
The international research community has been attracted to the concept of a “water-energy-food” nexus as an approach for more integrated planning for global environmental change. The Sustainable Development Goals may well be approached using such a nexus approach for data gathering and for holistic policy implementation. This chapter considers how Central and South Asia might adopt this approach, particularly in the context of rapid development which is taking place across the region. We focus on energy efficiency and public-private partnerships as two key areas where robust metrics for such a nexus being realized hold promise. We also consider some of the criticism of the nexus approach in terms of research depth and policy implementation and the use of tools such as the Water Energy Food Nexus Index in the context of this region. Overall, we find the concept is appropriate for use in this region, particularly as a means of cross-border and regional development planning.
Sensor-based measurements of NDVI in small grain and corn fields by tractor, drone, and satellite platforms
(Crop and Environment, 2024-02-01) Miller, Jarrod O.; Mondal, Pinki; Sarupria, Manan
The use of sensors for variable rate nitrogen (VRN) applications is transitioning from equipment-based to drone and satellite technologies. However, regional algorithms, initially designed for proximal active sensors, require evaluation for compatibility with remotely sensed reflectance and N-rate predictions. This study observed normalized difference vegetation index (NDVI) data from six small grain and two corn fields over three years. We employed three platforms: tractor-mounted active sensors (T-NDVI), passive multispectral drone (D-NDVI), and satellite (S-NDVI) sensors. Averaged NDVI values were extracted from the as-applied equipment polygons. Correlations between NDVI values from the three platforms were positive and strong, with D-NDVI consistently recording the highest values, particularly in areas with lower plant biomass. This was attributed to D-NDVI's lower soil reflectance and its ability to measure the entire biomass within equipment polygons. For small grains, sensors spaced on equipment booms might not capture accurate biomass in poor-growing and low NDVI regions. Regarding VRN, S-NDVI and D-NDVI occasionally aligned with T-NDVI recommendations but often suggested half the active sensor rate. Final yields showed some correlation with landscape variables, irrespective of N application. This finding suggests the potential use of drone or satellite imagery to provide multiple NDVI maps before application, incorporating expected landscape responses and thereby enhancing VRN effectiveness.
Editorial: Transboundary conservation
(Frontiers in Conservation Science, 2024-01-24) Wang, Lin; Ali, Saleem H.; Thornton, Daniel H.; Farhadinia, Mohammad S.
Transboundary areas often contain critical ecosystems that support rich biodiversity and play important roles in maintaining ecological connectivity. More than half of terrestrial vertebrate species have ranges spanning international borders. Many species may shift their distributions by crossing international borders in response to climate change or human disturbances. Yet species in transboundary regions are in increasing peril due to uncoordinated management among neighboring countries and artificial barriers, such as walls and fences along borders and cross-border roads that result in habitat fragmentation and the loss of ecological connectivity. Transboundary conservation can significantly contribute to ongoing efforts to reduce the risk of future extinctions by expanding protected areas and promoting collaborative management. Therefore, more attention to this topic is urgently needed. The Research Topic of Transboundary Conservation aims to enhance understanding of the potential, patterns, and effects of transboundary conservation by collecting studies that analyze transboundary conservation across different terrestrial and marine landscapes. Simultaneously, it aspires towards broader goals of international environmental governance and security.
Estimating forest extent across Mexico
(Environmental Research Letters, 2024-01-12) Braden, Dustin; Mondal, Pinki; Park, Taejin; Alanís de la Rosa, José Armando; Aldrete Leal, Metzli Ileana; Cuenca Lara, Rubi Angélica; Mayorga Saucedo, Rafael; Paz, Fernando; Salas-Aguilar, Victor Manuel; Soriano-Luna, María De Los Ángeles; Vargas, Rodrigo
Information on forest extent and tree cover is required to evaluate the status of natural resources, conservation practices, and environmental policies. The challenge is that different forest definitions, remote sensing-based (RSB) products, and data availability can lead to discrepancies in reporting total forest area. Consequently, errors in forest extent can be propagated into forest biomass and carbon estimates. Here, we present a simple approach to compare forest extent estimates from seven regional and global land or tree cover RSB products at 30 m resolution across Mexico. We found substantial differences in forest extent estimates for Mexico, ranging from 387 607 km2 to 675 239 km2. These differences were dependent on the RSB product and forest definition used. Next, we compared these RSB products with two independent forest inventory datasets at national (n = 26 220 plots) and local scales (n = 754 plots). The greatest accuracy among RSB products and forest inventory data was within the tropical moist forest (range 82%–95%), and the smallest was within the subtropical desert (range <10%–80%) and subtropical steppe ecological zones (range <10%–60%). We developed a forest extent agreement map by combining seven RSB products and identifying a consensus in their estimates. We found a forest area of 288 749 km2 with high forest extent agreement, and 340 661 km2 with medium forest extent agreement. The high-to-medium forest extent agreement of 629 410 km2 is comparable to the official national estimate of 656 920 km2. We found a high forest extent agreement across the Yucatan Peninsula and mountain areas in the Sierra Madre Oriental and Sierra Madre Occidental. The tropical dry forest and subtropical mountain system represent the two ecological zones with the highest areas of disagreement among RSB products. These findings show discrepancies in forest extent estimates across ecological zones in Mexico, where additional ground data and research are needed. Dataset available at https://doi.org/10.3334/ORNLDAAC/2320.
Half of twenty-first century global irrigation expansion has been in water-stressed regions
(Nature Water, 2024-03-08) Mehta, Piyush; Siebert, Stefan; Kummu, Matti; Deng, Qinyu; Ali, Tariq; Marston, Landon; Xie, Wei; Davis, Kyle Frankel
The expansion of irrigated agriculture has increased global crop production but resulted in widespread stress on freshwater resources. Ensuring that increases in irrigated production occur only in places where water is relatively abundant is a key objective of sustainable agriculture and knowledge of how irrigated land has evolved is important for measuring progress towards water sustainability. Yet, a spatially detailed understanding of the evolution of the global area equipped for irrigation (AEI) is missing. In this study, we used the latest subnational irrigation statistics (covering 17,298 administrative units) from various official sources to develop a gridded (5 arcmin resolution) global product of AEI for the years 2000, 2005, 2010 and 2015. We found that AEI increased by 11% from 2000 (297 Mha) to 2015 (330 Mha), with areas of both substantial expansion, such as northwest India and northeast China, and decline, such as Russia. Combining these outputs with information on green (that is, rainfall) and blue (that is, surface and ground) water stress, we also examined to what extent irrigation has expanded unsustainably in places already experiencing water stress. We found that more than half (52%) of the irrigation expansion has taken place in areas that were already water-stressed in the year 2000, with India alone accounting for 36% of global unsustainable expansion. These findings provide new insights into the evolving patterns of global irrigation with important implications for global water sustainability and food security.
Assessing and addressing the global state of food production data scarcity
(Nature Reviews Earth & Environment, 2024-02-20) Kebede, Endalkachew Abebe; Abou Ali, Hanan; Clavelle, Tyler; Froehlich, Halley E.; Gephart, Jessica A.; Hartman, Sarah; Herrero, Mario; Kerner, Hannah; Mehta, Piyush; Nakalembe, Catherine; Ray, Deepak K.; Siebert, Stefan; Thornton, Philip; Davis, Kyle Frankel
Food production data — such as crop, livestock, aquaculture and fisheries statistics — are critical to achieving multiple sustainable development goals. However, the lack of reliable, regularly collected, accessible, usable and spatially disaggregated statistics limits an accurate picture of the state of food production in many countries and prevents the implementation of effective food system interventions. In this Review, we take stock of national and international food production data to understand its availability and limitations. Across databases, there is substantial global variation in data timeliness, granularity (both spatially and by food category) and transparency. Data scarcity challenges are most pronounced for livestock and aquatic food production. These challenges are largely concentrated in Central America, the Middle East and Africa owing to a combination of inconsistent census implementation and a global reliance on self-reporting. Because data scarcity is the result of technical, institutional and political obstacles, solutions must include technological and policy innovations. Fusing traditional and emerging data-gathering techniques with coordinated governance and dedicated long-term financing will be key to overcoming current obstacles to sustained, up-to-date and accurate food production data collection, foundational in promoting and monitoring progress towards healthier and more sustainable food systems worldwide.
Focus on the future of water-limited agricultural landscapes
(Environmental Research Letters, 2024-01-19) Peterson, Caitlin A.; Davis, Kyle Frankel; Dybala, Kristen E.; Fernández, Francisco J.; Ghimire, Rajan; Nidumolu, Uday; Roche, Rose
Water scarcity and related climate volatility are growing constraints on agricultural production landscapes around the world. While the adaptation options available are often dictated by system context, in many places broad-scale transformations are occurring in response to water-related pressures. We sought contributions from across regions, agricultural system types, and scientific disciplines to examine agricultural land use transitions driven by water scarcity, including the tradeoffs associated with alternative land uses; impacts on food production, environment, and society; innovations that can buffer risk; and considerations for planning and implementation. The research presented in this collection highlights the spectrum of policy and practice changes that are needed to facilitate beneficial land use transitions and system transformations, from quantifying risks, to evaluating multidimensional tradeoffs, to developing socio-technical policy bundles to maximize co-benefits.
The motivations, challenges and needs of small- and medium-scale beginning farmers in the midwestern United States
(Journal of Agriculture, Food Systems, and Community Development, 2023-04-27) Iles, Keri; Nixon, Rebecca; Ma, Zhao; Gibson, Kevin; Benjamin, Tamara
Beginning farmers are increasingly recognized as important agricultural actors in the United States. Efforts to help interested individuals enter agriculture have increased; however, there is still a substantial knowledge gap regarding beginning farmers’ characteristics, motivations to farm, challenges, and information and resource needs, particularly among those who operate small or medium-sized farms. In this research, we collected and analyzed survey data in Indiana to gain a better understanding of small- and medium-scale beginning farmers in the midwestern United States. We found that small- and medium-scale beginning farmers were motivated by their desire for a farming lifestyle and to support local food and agroecological farming systems on a landscape dominated by commodity crops. They relied substantially on off-farm income and faced related challenges including limited access to labor and difficulty balancing their on-farm and off-farm responsibilities. Finding effective marketing strategies also challenged this group of farmers, as they were not well-integrated into existing agricultural programs, and many had limited interactions with agricultural agencies and organizations. Instead, the majority of small- and medium-scale beginning farmers relied heavily on their own internet research and informal interactions with other farmers to learn and obtain help for their farms. Together, our results contribute to a better understanding of small- and medium-scale beginning farmers’ characteristics, motivations, and farming practices, as well as the challenges they face and the support they need to address these challenges. Because beginning farmers often differ from their more established counterparts who operate larger farms, the results of this research can be used to inform tailored agricultural programs and technical assistance that address small- and medium-scale beginning farmers’ specific needs and challenges in order to increase their likelihood of success to not only start but also sustain a small- or medium-scale farm over time.
Effects of forest thinning on sap flow dynamics and transpiration in a Japanese cedar forest
(Science of the Total Environment, 2023-12-20) Iida, Shin'ichi; Noguchi, Shoji; Levia, Delphis F.; Araki, Makoto; Nitta, Kyohei; Wada, Satoru; Narita, Yoshito; Tamura, Hiroki; Abe, Toshio; Kaneko, Tomonori
Historically, forest thinning in Japan was conducted to obtain high-quality timber from plantations. Today, in contrast, thinning is also motivated by forest water balance and climate change considerations. It is in this context that the present study examines the effects of thinning on the ecophysiological responses of remaining trees, which are inadequately understood, especially in relation to changes in the magnitude and duration of transpiration. Sap flux densities were measured in both outer and inner sapwood to obtain stand-scale transpiration for two years in the pre-thinning state and three years post-thinning. The effects of thinning on transpiration were quantitatively evaluated based on canopy conductance models. The larger increases in outer sap flux density were found in the first year after the treatment, while those in inner sap flux density were detected in the second and third years. The remaining trees required a few of years to adjust to improved light conditions of the lower crown, resulting in a delayed response of inner sap flux density. As a result of this lag, transpiration was reduced to 71 % of the pre-thinning condition in the first year, but transpiration recovered to the pre-thinning levels in the second and third years due to compensating contributions from inner sap flow. In terms of more accurately chronicling the thinning effect, the distribution of sap flux density with respect to its radial pattern, is necessary. Such measurements are key to more comprehensively examining the ecophysiological response of forest plantations to thinning and, ultimately, its effect on the forest water balance. Highlights • Transpiration (TR) was measured for two years before and three years post thinning. • Outer sap flux increased immediately, while inner increase was delayed. • TR decreased to 71 % just after thinning, returning to initial levels in 2–3 years. • Delayed but substantial increase of inner sap flow is a main factor for TR variation. • Both outer and inner sap fluxes must be quantified to evaluate thinning effects. Graphical abstract available at: https://doi.org/10.1016/j.scitotenv.2023.169060
Atmospheric Drivers Associated with Extreme Snow Ablation and Discharge Events in the Susquehanna River Basin: A Climatology
(Journal of Applied Meteorology and Climatology, 2023-11-02) Suriano, Zachary J.; Henderson, Gina R.; Arthur, Julia; Harper, Kricket; Leathers, Daniel J.
Extreme snow ablation can greatly impact regional hydrology, affecting streamflow, soil moisture, and groundwater supplies. Relatively little is known about the climatology of extreme ablation events in the eastern United States, and the causal atmospheric forcing mechanisms behind such events. Studying the Susquehanna River basin over a 50-yr period, here we evaluate the variability of extreme ablation and river discharge events in conjunction with a synoptic classification and global-scale teleconnection pattern analysis. Results indicate that an average of 4.2 extreme ablation events occurred within the basin per year, where some 88% of those events resulted in an increase in river discharge when evaluated at a 3-day lag. Both extreme ablation and extreme discharge events occurred most frequently during instances of southerly synoptic-scale flow, accounting for 35.7% and 35.8% of events, respectively. However, extreme ablation was also regularly observed during high pressure overhead and rain-on-snow synoptic weather types. The largest magnitude of snow ablation per extreme event occurred during occasions of rain-on-snow, where a basinwide, areal-weighted 5.7 cm of snow depth was lost, approximately 23% larger than the average extreme event. Interannually, southerly flow synoptic weather types were more frequent during winter seasons when the Arctic and North Atlantic Oscillations were positively phased. Approximately 30% of the variance in rain-on-snow weather type frequency was explained by the Pacific–North American pattern. Evaluating the pathway of physical forcing mechanisms from regional events up through global patterns allows for improved understanding of the processes resulting in extreme ablation and discharge across the Susquehanna basin. Significance Statement The purpose of this study is to better understand how certain weather patterns are related to extreme snowmelt and streamflow events and what causes those weather patterns to vary with time. This is valuable information for informing hazard preparation and resource management within the basin. We found that weather patterns with southerly winds were the most frequent patterns responsible for extreme melt and streamflow, and those patterns occurred more often when the Arctic and North Atlantic Oscillations were in their “positive” configuration. Future work should consider the potential for these patterns, and related impacts, to change over time.
Comparison of Extreme Coastal Flooding Events between Tropical and Midlatitude Weather Systems in the Delaware and Chesapeake Bays for 1980–2019
(Journal of Applied Meteorology and Climatology, 2022-04-26) Callahan, John A.; Leathers, Daniel J.; Callahan, Christina L.
Coastal flooding is one of the most costly and deadly natural hazards facing the U.S. mid-Atlantic region today. Impacts in this heavily populated and economically significant region are caused by a combination of the location’s exposure and natural forcing from storms and sea level rise. Tropical cyclones (TCs) and midlatitude (ML) weather systems each have caused extreme coastal flooding in the region. Skew surge was computed over each tidal cycle for the past 40 years (1980–2019) at several tide gauges in the Delaware and Chesapeake Bays to compare the meteorological component of surge for each weather type. Although TCs cause higher mean surges, ML weather systems can produce surges just as severe and occur much more frequently, peaking in the cold season (November–March). Of the top 10 largest surge events, TCs account for 30%–45% in the Delaware and upper Chesapeake Bays and 40%–45% in the lower Chesapeake Bay. This percentage drops to 10%–15% for larger numbers of events in all regions. Mean sea level pressure and 500-hPa geopotential height (GPH) fields of the top 10 surge events from ML weather systems show a low pressure center west-southwest of “Delmarva” and a semistationary high pressure center to the northeast prior to maximum surge, producing strong easterly winds. Low pressure centers intensify under upper-level divergence as they travel eastward, and the high pressure centers are near the GPH ridges. During lower-bay events, the low pressure centers develop farther south, intensifying over warmer coastal waters, with a south-shifted GPH pattern relative to upper-bay events. Significance Statement Severe coastal flooding is a year-round threat in the U.S. mid-Atlantic region, and impacts are projected to increase in magnitude and frequency. Research into the meteorological contribution to storm surge, separate from mean sea level and tidal phase, will increase the scientific understanding and monitoring of changing atmospheric conditions. Tropical cyclones and midlatitude weather systems both significantly impact the mid-Atlantic region during different times of year. However, climate change may alter the future behavior of these systems differently. Understanding the synoptic environment and quantifying the surge response and subbay geographic variability of each weather system in this region will aid in public awareness, near-term emergency preparation, and long-term planning for coastal storms.

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