Center-pivot irrigation systems started in the United States in the mid-20th century as an irrigation method which surpassed the traditional surface irrigation methods. At that time, they had the potential to bring about higher irrigation efficiencies with less water consumption although their requirements in energy were higher too. Among their benefits, it is highlighted the feasibility to control water management as well as the application of agro-chemicals dissolved in the irrigation water and thus, center-pivot irrigation systems have spread worldwide. Nevertheless, since the last decade of the 20th century, they are facing actual concerns regarding ecosystem sustainability and water and energy efficiencies. Likewise, the 21st century has brought about the cutting edge issue “precision irrigation” which has made feasible the application of water, fertilizers, and chemicals as the plant demands taking into account variables such as: sprinkler´s pressure, terrain topography, soil variability, and climatic conditions. Likewise, it could be adopted to deal with the current key issues regarding the sustainability and efficiency of the center-pivot irrigation to maintain the agro-ecosystems but still, other issues such as the organic matter incorporation are far to be understood and they will need further studies.
Article
Environmental Benefits and Concerns of Center-Pivot Irrigation
Leonor Rodriguez Sinobas
Article
Environmental Impacts and Benefits of Agroforestry
Shibu Jose
Agroforestry systems, the planting of perennial trees and/or shrubs with annual agronomic crops or pasture, have been proposed as more environmentally benign, alternative systems for agricultural production in both temperate and tropical regions of the world. Agroforestry provides a number of environmental benefits as confirmed by scientific literature. The four major environmental benefits of agroforestry are (1) climate change mitigation through carbon sequestration, (2) biodiversity conservation, (3) soil health enrichment, and (4) air and water quality improvement. In addition to environmental benefits, the economic benefits of multiple crops within agroforestry systems have also generated interest in their adoption by farmers the world over. The major negative impacts come from conversion or degradation of forests following certain traditional practices, which may not fit in the definition of modern agroforestry. Challenges remain for widespread adoption of agroforestry, particularly in the temperate world; however, a new resurgence of interest in this land-use practice among small-scale farmers has shed light on a path toward its possible success. Past evidence clearly indicates that agroforestry, as part of a multifunctional working landscape, can offer not only economic return, but also a number of ecosystem services and environmental benefits for a sustainable society.
Article
Environmental Impacts of Tropical Soybean and Palm Oil Crops
Kimberly M. Carlson and Rachael D. Garrett
Oil crops play a critical role in global food and energy systems. Since these crops have high oil content, they provide cooking oils for human consumption, biofuels for energy, feed for animals, and ingredients in beauty products and industrial processes. In 2014, oil crops occupied about 20% of crop harvested area worldwide. While small-scale oil crop production for subsistence or local consumption continues in certain regions, global demand for these versatile crops has led to substantial expansion of oil crop agriculture destined for export or urban markets. This expansion and subsequent cultivation has diverse effects on the environment, including loss of forests, savannas, and grasslands, greenhouse gas emissions, regional climate change, biodiversity decline, fire, and altered water quality and hydrology. Oil palm in Southeast Asia and soybean in South America have been identified as major proximate causes of tropical deforestation and environmental degradation. Stringent conservation policies and yield increases are thought to be critical to reducing rates of soybean and oil palm expansion into natural ecosystems. However, the higher profits that often accompany greater yields may encourage further expansion, while policies that restrict oil crop expansion in one region may generate secondary “spillover” effects on other crops and regions. Due to these complex feedbacks, ensuring a sustainable supply of oil crop products to meet global demand remains a major challenge for agricultural companies, farmers, governments, and civil society.
Article
Evolution of Agricultural Practices and the Transformation of the English Landscape
Tom Williamson
Agriculture has been the principal influence on the physical structure of the English landscape for many thousands of years. Driven by a wider raft of demographic, social, and economic developments, farming has changed in complex ways over this lengthy period, with differing responses to the productive potential and problems of local environments leading to the emergence of distinct regional landscapes. The character and configuration of these, as much as any contemporary influences, have in turn structured the practice of agriculture at particular points in time. The increasing complexity of the wider economy has also been a key influence on the development of the farmed landscape, especially large-scale industrialization in the late 18th and 19th centuries; and, from the late 19th century, globalization and increasing levels of state intervention. Change in agricultural systems has not continued at a constant rate but has displayed periods of more and less innovation.
Article
The Family of HYDRUS Models
Jiří Šimůnek, Giuseppe Brunetti, Martinus Th. van Genuchten, and Miroslav Šejna
HYDRUS is a Windows-based modeling software package that can be used to analyze water flow and heat and solute transport in variably saturated porous media (e.g., soils or the vadose zone). The HYDRUS software includes an interactive graphics-based interface for data preprocessing, soil profile discretization, and graphic presentation of the results. Historically, HYDRUS consisted of two independent software packages. While HYDRUS-1D simulated flow and transport processes in one dimension and was a public domain software, HYDRUS (2D/3D; and earlier HYDRUS-2D) extended the simulation capabilities to the second and third dimensions and was distributed commercially. These two previously independent software packages were merged in 2023 into a single software package called HYDRUS.
The capabilities of the HYDRUS software packages have been significantly expanded by various standard and nonstandard specialized add-on modules. The standard add-on modules are fully incorporated and supported by the HYDRUS graphical user-friendly interfaces (GUIs) and documented in detail in the technical and user manuals. This is not the case for several additional nonstandard modules, which require additional work outside the GUI. A commonality of all HYDRUS add-on modules is that they simulate variably saturated water flow and heat and solute transport in porous media. The specialized add-on modules provide additional capabilities, such as considering general reactive transport (in the HPx models) or reactive transport with specific chemistry (notably the Wetland and UNSATCHEM modules). Other modules provide additional flow and/or transport modeling processes, such as to account for preferential flow (the DualPerm module), colloid-facilitated solute transport (the C-Ride module), or the transport of polyfluoroalkyl substances (PFAS; the PFAS module) or fumigant (the Fumigant module) compounds.
The HYDRUS models are among the most widely used numerical models for simulating processes in the subsurface. There are many thousands of HYDRUS users worldwide, with many applications (also several thousand) appearing in peer-reviewed international literature and many technical reports.
Article
Field-Level Irrigation
Kiril Manevski and Mathias Neumann Andersen
Field irrigation is the largest consumer of freshwater in the world covering 63 million hectares in the 1900s to 300 million hectares in the early 2000s to provide a multitude of benefits and ecosystem services to people around the globe, such as consistent food supply, higher crop productivity, and shared resource collectivism. Field irrigation intensifies land use mostly in the arid and the semiarid regions where precipitation cannot fully satisfy human and crop water demands. Climate change impacts the distribution and the timing of water availability into humid regions as well through increases in drought frequency and intensity, further augmenting the demand for irrigation. However, designing and operating irrigation infrastructure and scheduling practices for an agricultural region requires sound contemporary and historical knowledge of the local circumstances vis-à-vis humans, crops, soils, hydrology, and climate. Sub-Saharan Africa stands as a large-scale narrative of poorly performing field irrigation against decades of investments due to designs exclusive to the socioeconomic ecosystems. Optimal water allocation in the water–energy–environment–food nexus to achieve the greatest social and economic benefit for the region invariably a task of continuous cocreation between many actors. Therefore, field irrigation remains a challenging project and most of the agricultural water use worldwide—both from groundwater and surface water—remains suboptimal in terms of design, water allocation, and monitoring for farmers, communities, and regulators. Many diversions of surface water for irrigation in both economically developed and developing countries are small-scale temporary infrastructures in and outside official plans and permits, which altogether results in severe aquifer depletion worldwide with negative impacts on food safety, economy, environment, and society.
Traditional surface flooding is the dominant mode of irrigation globally and mostly applied on new agricultural fields, whereas water-saving irrigation methods are practiced on fewer and older fields. Water-saving technologies involve either scheduling of regulated deficit irrigation or local water storage to optimize crop water supply, which may be combined with drip irrigation, biodegradable soil amendments to retain soil water, and plastic mulches to minimize evaporation, whereas the use of partial root zone drying and biochar mostly remain at the experimental stage. Global analyses over the late 20th and early 21st century find no water saving by water-saving technologies at field scale because increased return flow from newly irrigated fields surpasses the reduced soil evaporation from old, irrigated fields, whereas regionally, return flow to fresh aquifers is a benefit rather than a loss, which results in some water savings. At the same time, increased crop transpiration exceeds regional water savings, which explains the paradox between the wide application of water-saving technologies and more severe regional water shortage.
With nonscientific decisions on when and where to irrigate practiced by most farmers worldwide, scheduling remains the top priority task in field irrigation, as both too little and too much water leads to yield decreases and loss of nutrients to the environment. Where water is abundant, scheduling aims to keep crop transpiration and yield at a maximum with minimum use of irrigation water. In dryer areas, this luxury can rarely be sustained unless the irrigation area and therefore production is reduced. Instead, regulated deficit irrigation may be practiced on drought-tolerant crops and cultivars. Regulated deficit irrigation seeks to limit crop transpiration to a fraction of the maximum during less drought-sensitive growth stages. In this way, crop water use efficiency increases, and yield per m3 of water rather than m2 of land is maximized. Remote sensing of soil and crops through satellite and aerial multispectral and thermal products have the potential to enhance irrigation scheduling by precisely quantifying and distinguishing crop transpiration (beneficial water consumption) from soil evaporation (nonbeneficial water loss) in space and time and to facilitate regulated deficit irrigation and other water-saving measures. However, irrigation management significantly falls behind in adapting state of the art information and communication technologies.
With a global rise in frequency and duration of droughts, the lack of irrigation infrastructure in humid regions and of water availability in semiarid regions induces enormous losses in agricultural production and social well-being and unveils an urgent need for a macrolevel drought governance approach in order to strengthen multisectoral water management and mitigate climate change damage to human and natural assets.
Article
Food Safety in a Global Economy: Policies and Social Issues
Tomiko Yamaguchi and Shun-Nan Chiang
Food safety has been a critical issue from the beginning of human existence, but more recently the nature of concerns over food safety has changed. Further, in terms of both scale and impact, the modern problems of food safety are very different from the issues that confronted the past. For example, especially since the late 1990s, society has faced food safety crises and scares arising from threats as diverse as bovine spongiform encephalitis (BSE), dioxin contamination, melamine-tainted infant milk formula, and so forth. These phenomena show that an ever-increasing variety of contaminants such as chemical and microbial agents can potentially find their way into the food supply, while novel foods such as GM foods and cultured meat add new challenges when it comes to certifying food safety.
Food safety has become a particularly complex issue in the context of the global economy because the governance of food safety is entangled with several larger trends at the global scale, including (a) trade liberalization in the 1980s; (b) the adoption of a risk analysis framework by global and national food safety administrations; and (c) the spread of food quality management regimes throughout the entire food industry, from food production to processing and retail. Furthermore, there are vast differences between developed and developing countries with respect to both food safety regulations and prominent food safety issues. These facts, combined with the borderless nature of sociotechnical food systems, contribute to a situation in which it is extremely challenging for any individual country to manage food safety issues within its jurisdiction. This observation underscores the importance of global food safety governance, a goal which is in itself difficult to achieve.
Two especially significant dilemmas have emerged within the existing situation vis-à-vis global food safety governance. The first is the challenges arising from the tensions inherent in a “modern” food safety governance approach, a model that combines a science-based strategy of dealing with food safety problems, on one hand, and the ideal of participatory democracy, on the other hand, in trying to deal with food safety issues. Problems arise from the contradictions between the science-based risked management approach, focused narrowly on monitoring and mitigation of hazards, and the wide-ranging complexity of the social, political, and interpersonal factors that shape people’s real-world concerns about food safety. The second is cross-border application of risk management to food imports in the Global North and its implications for exporting countries in the Global South. Problems arise from disparities in approaches and expectations regarding food safety between the Global North and the South. These two dilemmas have one thing in common: Each inherently contains challenges arising from internal contractions, as when the goal of achieving sound and consistent solutions to food safety issues is pursued alongside the goal of building a broad consensus across varying actors whose values, norms, needs, and interests differ and who are situated in differing socioeconomic and political contexts. Drawing insights from the sociology of agriculture and food and from social studies of science, an attempt is made to unpack the societal and policy challenges of food safety governance in a globalized economy.
Article
Food Sovereignty
Mieke van Hemert
Food sovereignty is a paradigm on food system transformation advanced by peasant organizations worldwide in response to the commoditization of food through free trade agreements, deteriorating environmental and livelihood conditions in rural areas, and marginalization of the peasantry. Food sovereignty is an alternative to the current global, industrial corporate food regime and involves changes at all levels of the food system with relocalization, regaining control over territories, and agroecological production as key strivings. Food is viewed as a basic human right, as opposed to a commodity. Domestic consumption and food self-sufficiency have priority over long-distance trade. Food is regarded as a part of culture, heritage, and cosmovision. Agroecological practices that restore agrobiodiversity and lessen dependence and indebtedness of farmers are to replace monocultures, which are highly dependent on external inputs and harmful to the environment. There is a central role for smallholders and rural peoples in food production, who should (re)gain control over land and territories, individually and collectively, especially women. This is to be realized through forms of agrarian reform that go beyond land redistribution. Societal change toward peaceful coexistence, equality, and care for the earth is an ultimate goal.
Food sovereignty is a research topic in a wide range of disciplines, including sociology, anthropology, geography, law, philosophy, history, agronomy, and ecology, alongside transdisciplinary research on food systems. While first advanced as a mobilizing concept by the transnational agrarian movement La Vía Campesina in 1996, food sovereignty has become a policy framework adopted by various governments and international organizations. The movement has successfully lobbied the United Nations and the Food and Agriculture Organization to adopt new rights and guidelines that bring obligations for governments to protect rural peoples against transnational corporations undermining their access to land, water, forests, and seeds. The movement itself has diversified, and its definition of food sovereignty has evolved and become more inclusive.
The food sovereignty paradigm has been criticized for being too expansive, complex, and unclear. Analyses of the competing discourses of food sovereignty and food security reveal contrasts and complementarities. Scholarly debate has also focused on the position of both peasants and farm workers in the capitalist economy and on processes of de- and repeasantization.
Societal and scholarly debate on the various dimensions of food sovereignty is ongoing. Academic research foregrounds fundamental questions, including what role the state is expected to play, what forms of trade are envisaged, how the rights approach functions, the interplay of different transformative processes, changing economic and ecological contexts, tensions between different social groups, and power-related challenges. The number of case studies on the struggle for food sovereignty is growing and exhibits wide geographical diversity.
Article
Food Waste and Biomass Recovery
Wun Jern Ng, Keke Xiao, Vinay Kumar Tyagi, Chaozhi Pan, and Leong Soon Poh
Agriculture waste can be a significant issue in waste management as its impact can be felt far from its place of origin. Post-harvest crop residues require clearance prior to the next planting and a common practice is burning on the field. The uncontrolled burning results in air pollution and can adversely impact the environment far from the burn site. Agriculture waste can also include animal husbandry waste such as from cattle, swine, and poultry. Animal manure not only causes odors but also pollutes water if discharged untreated. However, agricultural activities, particularly on a large scale, are typically at some distance from urban centers. The environmental impacts associated with production may not be well recognized by the consumers. As the consumption terminal of agricultural produce, urban areas in turn generate food waste, which can contribute significantly to municipal solid wastes. There is a correlation between the quantity of food waste generated and a community’s economic progress.
Managing waste carries a cost, which may illustrate cost transfer from waste generators to the public. However, waste need not be seen only as an unwanted material that requires costly treatment before disposal. The waste may instead be perceived as a raw material for resource recovery. For example, the material may have substantial quantities of organic carbon, which can be recovered for energy generation. This offers opportunity for producing and using renewable and environment-friendly fuels. The “waste” may also include quantities of recoverable nutrients such as nitrogen and phosphorus.
Article
The Forest Transition
Thomas Rudel
Forest transitions take place when trends over time in forest cover shift from deforestation to reforestation. These transitions are of immense interest to researchers because the shift from deforestation to reforestation brings with it a range of environmental benefits. The most important of these would be an increased volume of sequestered carbon, which if large enough would slow climate change. This anticipated atmospheric effect makes the circumstances surrounding forest transitions of immediate interest to policymakers in the climate change era. This encyclopedia entry outlines these circumstances. It begins by describing the socio-ecological foundations of the first forest transitions in western Europe. Then it discusses the evolution of the idea of a forest transition, from its introduction in 1990 to its latest iteration in 2019. This discussion describes the proliferation of different paths through the forest transition. The focus then shifts to a discussion of the primary driver of the 20th-century forest transitions, economic development, in its urbanizing, industrializing, and globalizing forms. The ecological dimension of the forest transition becomes the next focus of the discussion. It describes the worldwide redistribution of forests toward more upland settings. Climate change since 2000, with its more extreme ecological events in the form of storms and droughts, has obscured some ongoing forest transitions. The final segment of this entry focuses on the role of the state in forest transitions. States have become more proactive in managing forest transitions. This tendency became more marked after 2010 as governments have searched for ways to reduce carbon emissions or to offset emissions through more carbon sequestration. The forest transitions by promoting forest expansion would contribute additional carbon offsets to a nation’s carbon budget. For this reason, the era of climate change could also see an expansion in the number of promoted forest transitions.
Article
From Plows, Horses, and Harnesses to Precision Technologies in the North American Great Plains
David E. Clay, Sharon A. Clay, Thomas DeSutter, and Cheryl Reese
Since the discovery that food security could be improved by pushing seeds into the soil and later harvesting a desirable crop, agriculture and agronomy have gone through cycles of discovery, implementation, and innovation. Discoveries have produced predicted and unpredicted impacts on the production and consumption of locally produced foods. Changes in technology, such as the development of the self-cleaning steel plow in the 18th century, provided a critical tool needed to cultivate and seed annual crops in the Great Plains of North America. However, plowing the Great Plains would not have been possible without the domestication of plants and animals and the discovery of the yoke and harness. Associated with plowing the prairies were extensive soil nutrient mining, a rapid loss of soil carbon, and increased wind and water erosion. More recently, the development of genetically modified organisms (GMOs) and no-tillage planters has contributed to increased adoption of conservation tillage, which is less damaging to the soil. In the future, the ultimate impact of climate change on agronomic practices in the North American Great Plains is unknown. However, projected increasing temperatures and decreased rainfall in the southern Great Plains (SGP) will likely reduce agricultural productivity. Different results are likely in the northern Great Plains (NGP) where higher temperatures can lead to increased agricultural intensification, the conversion of grassland to cropland, increased wildlife fragmentation, and increased soil erosion. Precision farming, conservation, cover crops, and the creation of plants better designed to their local environment can help mitigate these effects. However, changing practices require that farmers and their advisers understand the limitations of the soils, plants, and environment, and their production systems. Failure to implement appropriate management practices can result in a rapid decline in soil productivity, diminished water quality, and reduced wildlife habitat.
Article
Geography and Chronology of the Transition to Agriculture
Peter Bogucki
After millennia of hunting and gathering, prehistoric human societies around the world made the transition to food production using domesticated plants and animals. Several key areas for the initial domestication of plants and animals can be identified: southwestern Asia, Mesoamerica, China, Neotropical South America, eastern North America, Highland New Guinea, and sub-Saharan Africa. In the Old World, wheat, barley, millet, rice, sheep, goats, cattle, and pigs were the major founding crops, while in the New World, maize, squashes, beans, and many other seed and tuber plants were brought into cultivation. Although each area had its own distinct pathway to agriculture, it typically followed a standard path from resource management by hunter-gatherers, incipient cultivation (and livestock herding in some areas), domestication, to commitment to agriculture. Many theories to explain the transition to agriculture have been proposed. Early single-factor hypotheses have been largely discarded in favor models drawn from human evolutionary biology that emphasize the interplay between humans and the species targeted for domestication. Although within the long span of human history, the transition from hunting and gathering to farming in the last 10,000 years can be considered extraordinarily rapid, usually this process took decades, centuries, or even millennia when considered from the perspective of the human factors involved. From these core areas, agricultural practices dispersed, both through their integration into the plant and animal economies of hunter-gatherer societies and through the spread of farming populations. The transition to agriculture had consequences on a global scale, leading to social complexity and, in many cases, urban societies that would be impossible to imagine without agriculture.
Article
History of Agriculture in the United States
Pamela Riney-Kehrberg
Agriculture is at the very center of the human enterprise; its trappings are in evidence all around, yet the agricultural past is an exceptionally distant place from modern America. While the majority of Americans once raised a significant portion of their own food, that ceased to be the case at the beginning of the 20th century. Only a very small portion of the American population today has a personal connection to agriculture. People still must eat, but the process by which food arrives on their plates is less evident than ever. The evolution of that process, with all of its many participants, is the stuff of agricultural history. The task of the agricultural historian is to make that past evident, and usable, for an audience that is divorced from the production of food. People need to know where their food comes from, past and present, and what has gone into the creation of the modern food system.
Article
How Environmental Degradation Impoverishes the Poor
Edward B. Barbier
Globally, around 1.5 billion people in developing countries, or approximately 35% of the rural population, can be found on less-favored agricultural land (LFAL), which is susceptible to low productivity and degradation because the agricultural potential is constrained biophysically by terrain, poor soil quality, or limited rainfall. Around 323 million people in such areas also live in locations that are highly remote, and thus have limited access to infrastructure and markets. The households in such locations often face a vicious cycle of declining livelihoods, increased ecological degradation and loss of resource commons, and declining ecosystem services on which they depend. In short, these poor households are prone to a poverty-environment trap. Policies to eradicate poverty, therefore, need to be targeted to improve the economic livelihood, productivity, and income of the households located on remote LFAL. The specific elements of such a strategy include involving the poor in paying for ecosystem service schemes and other measures that enhance the environments on which the poor depend; targeting investments directly to improving the livelihoods of the rural poor, thus reducing their dependence on exploiting environmental resources; and tackling the lack of access by the rural poor in less-favored areas to well-functioning and affordable markets for credit, insurance, and land, as well as the high transportation and transaction costs that prohibit the poorest households in remote areas to engage in off-farm employment and limit smallholder participation in national and global markets.
Article
Human-Environmental Interrelationships and the Origins of Agriculture in Egypt and Sudan
Simon Holdaway and Rebecca Phillipps
Northeast Africa forms an interesting case study for investigating the relationship between changes in environment and agriculture. Major climatic changes in the early Holocene led to dramatic changes in the environment of the eastern Sahara and to the habitation of previously uninhabitable regions. Research programs in the eastern Sahara have uncovered a wealth of archaeological evidence for sustained occupation during the African Humid Period, from about 11,000 years ago. Initial studies of faunal remains seemed to indicate early shifts in economic practice toward cattle pastoralism. Although this interpretation was much debated when it was first proposed, the possibility of early pastoralism stimulated discussion concerning the relationships between people and animals in particular environmental contexts, and ultimately led to questions concerning the role of agriculture imported from elsewhere in contrast to local developments. Did agriculture, or indeed cultivation and domestication more generally (sensu Fuller & Hildebrand, 2013), develop in North Africa, or were the concepts and species imported from Southwest Asia? And if agriculture did spread from elsewhere, were just the plants and animals involved, or was the shift part of a full socioeconomic suite that included new subsistence strategies, settlement patterns, technologies, and an agricultural “culture”? And finally, was this shift, wherever and however it originated, related to changes in the environment during the early to mid-Holocene?
These questions refer to the “big ideas” that archaeologists explore, but before answers can be formed it is important to consider the nature of the material evidence on which they are based. Archaeologists must consider not only what they discover but also what might be missing. Materials from the past are preserved only in certain places, and of course some materials can be preserved better than others. In addition, people left behind the material remains of their activities, but in doing so they did not intend these remains to be an accurate historical record of their actions. Archaeologists need to consider how the remains found in one place may inform us about a range of activities that occurred elsewhere for which the evidence may be less abundant or missing. This is particularly true for Northeast Africa where environmental shifts and consequent changes in resource abundance often resulted in considerable mobility. This article considers the origins of agriculture in the region covering modern-day Egypt and Sudan, paying particular attention to the nature of the evidence from which inferences about past socioeconomies may be drawn.
Article
Hunter-Gatherer Economies in the Old World and New World
Christopher Morgan, Shannon Tushingham, Raven Garvey, Loukas Barton, and Robert L. Bettinger
At the global scale, conceptions of hunter-gatherer economies have changed considerably over time and these changes were strongly affected by larger trends in Western history, philosophy, science, and culture. Seen as either “savage” or “noble” at the dawn of the Enlightenment, hunter-gatherers have been regarded as everything from holdovers from a basal level of human development, to affluent, ecologically-informed foragers, and ultimately to this: an extremely diverse economic orientation entailing the fullest scope of human behavioral diversity. The only thing linking studies of hunter-gatherers over time is consequently simply the definition of the term: people whose economic mode of production centers on wild resources. When hunter-gatherers are considered outside the general realm of their shared subsistence economies, it is clear that their behavioral diversity rivals or exceeds that of other economic orientations. Hunter-gatherer behaviors range in a multivariate continuum from: a focus on mainly large fauna to broad, wild plant-based diets similar to those of agriculturalists; from extremely mobile to sedentary; from relying on simple, generalized technologies to very specialized ones; from egalitarian sharing economies to privatized competitive ones; and from nuclear family or band-level to centralized and hierarchical decision-making. It is clear, however, that hunting and gathering modes of production had to have preceded and thus given rise to agricultural ones. What research into the development of human economies shows is that transitions from one type of hunting and gathering to another, or alternatively to agricultural modes of production, can take many different evolutionary pathways. The important thing to recognize is that behaviors which were essential to the development of agriculture—landscape modification, intensive labor practices, the division of labor and the production, storage, and redistribution of surplus—were present in a range of hunter-gatherer societies beginning at least as early as the Late Pleistocene in Africa, Europe, Asia, and the Americas. Whether these behaviors eventually led to the development of agriculture depended in part on the development of a less variable and CO2-rich climatic regime and atmosphere during the Holocene, but also a change in the social relations of production to allow for hoarding privatized resources. In the 20th and 21st centuries, ethnographic and archaeological research shows that modern and ancient peoples adopt or even revert to hunting and gathering after having engaged in agricultural or industrial pursuits when conditions allow and that macroeconomic perspectives often mask considerable intragroup diversity in economic decision making: the pursuits and goals of women versus men and young versus old within groups are often quite different or even at odds with one another, but often articulate to form cohesive and adaptive economic wholes. The future of hunter-gatherer research will be tested by the continued decline in traditional hunting and gathering but will also benefit from observation of people who revert to or supplement their income with wild resources. It will also draw heavily from archaeology, which holds considerable potential to document and explain the full range of human behavioral diversity, hunter-gatherer or otherwise, over the longest of timeframes and the broadest geographic scope.
Article
An Image Reconnaissance: Agricultural Patterns and Related Environmental Impacts Viewed From Space
Richard W. Hazlett and Joshua Peck
Satellite reconnaissance of the Earth’s surface provides critical information about the state of human interaction with the natural environment. The strongest impact is agricultural, reflecting land-use approaches to food production extending back to the dawn of civilization. To variable degrees, depending upon location, regional field patterns result from traditional farming practices, surveying methods, regional histories, policies, political agendas, environmental circumstances, and economic welfare. Satellite imaging in photographic true or false color is an important means of evaluating the nature and implications of agricultural practices and their impacts on the surrounding world. Important platforms with publicly accessible links to satellite image sets include those of the European Space Agency, U.S. National Aeronautics and Space Administration, the Centre D’etudes Spatiales, Airbus, and various other governmental programs. Reprocessing of data worldwide in scope by commercial concerns including Digital Globe, Terrametrics, and GoogleEarth in the 21st century enable ready examination of most of the Earth’s surface in great detail and natural colors. The potential for monitoring and improving understanding of agriculture and its role in the Earth system is considerable thanks to these new ways of viewing the planet.
Space reconnaissance starkly reveals the consequences of unique land surveys for the rapid development of agriculture and political control in wilderness areas, including the U.S. Public Land Survey and Tierras Bajas systems. Traditional approaches toward agriculture are clearly shown in ribbon farms, English enclosures and medieval field systems, and terracing in many parts of the world. Irrigation works, some thousands of years old, may be seen in floodplains and dryland areas, notably the Maghreb and the deep Sahara, where center-pivot fields have recently appeared in areas once considered too dry to cultivate. Approaches for controlling erosion, including buffer zones, shelter belts, strip and contour farming, can be easily identified. Also evident are features related to field erosion and soil alteration that have advanced to crisis stage, such as badland development and widespread salinization. Pollution related to farm runoff, and the piecemeal (if not rapid) loss of farmlands due to urbanization can be examined in ways favoring more comprehensive evaluation of human impacts on the planetary surface. Developments in space technologies and observational platforms will continue indefinitely, promising ever-increasing capacity to understand how humans relate to the environment.
Article
Indigenous American Agricultural Contributions to Modern Global Food Systems
Maria C. Bruno
World food systems in the 21st century comprise domesticated plant and animal species that originated from nearly every continent on the globe, spread through exchange and trade, and have been taken up by farmers and cooks worldwide. The indigenous inhabitants of the Americas domesticated several of the worlds’ most important food crops, including maize, potatoes, chili peppers, and quinoa. They also domesticated several animal species, two of which, llamas and alpacas, have become important as alternative herd animals outside of their native Andes. While maize, potatoes, and chili peppers became important globally in the 16th and 17th centuries as part of the Columbian Exchange, llamas/alpacas and quinoa have only gained worldwide prominence in the 20th and 21st centuries.
Unraveling the history of how, where, when, and why these species were domesticated requires the expertise of researchers in the fields of biology, genetics, and archaeology. Domestication is the process by which humans transform wild plant or animal populations into forms that can only be maintained with human intervention. Humans build upon the natural variation in these species but select traits that while desirable for humans, would not be beneficial to survival without them. Using a range of evidence from the remains of ancient plants and animals recovered from archaeological sites to the study of the genetic relationships of living and ancient plant and animal populations, these researchers are revealing how ancient American populations created some of the world’s most important food sources.
Article
Indigenous Polynesian Agriculture in Hawaiʻi
Noa Kekuewa Lincoln and Peter Vitousek
Agriculture in Hawaiʻi was developed in response to the high spatial heterogeneity of climate and landscape of the archipelago, resulting in a broad range of agricultural strategies. Over time, highly intensive irrigated and rainfed systems emerged, supplemented by extensive use of more marginal lands that supported considerable populations. Due to the late colonization of the islands, the pathways of development are fairly well reconstructed in Hawaiʻi. The earliest agricultural developments took advantage of highly fertile areas with abundant freshwater, utilizing relatively simple techniques such as gardening and shifting cultivation. Over time, investments into land-based infrastructure led to the emergence of irrigated pondfield agriculture found elsewhere in Polynesia. This agricultural form was confined by climatic and geomorphological parameters, and typically occurred in wetter, older landscapes that had developed deep river valleys and alluvial plains. Once initiated, these wetland systems saw regular, continuous development and redevelopment. As populations expanded into areas unable to support irrigated agriculture, highly diverse rainfed agricultural systems emerged that were adapted to local environmental and climatic variables. Development of simple infrastructure over vast areas created intensive rainfed agricultural systems that were unique in Polynesia. Intensification of rainfed agriculture was confined to areas of naturally occurring soil fertility that typically occurred in drier and younger landscapes in the southern end of the archipelago. Both irrigated and rainfed agricultural areas applied supplementary agricultural strategies in surrounding areas such as agroforestry, home gardens, and built soils. Differences in yield, labor, surplus, and resilience of agricultural forms helped shape differentiated political economies, hierarchies, and motivations that played a key role in the development of sociopolitical complexity in the islands.
Article
Industrial Fertilizers in Agriculture
Gregory L. Willoughby
Agriculture has been said to be the key to civilization development. The longevity of the production of the soils which sustained the population development influenced, in fact caused, the rise and often the collapse of those ancient cultures. Furthermore, the fertilization of those soils, if by new sediment or by other means, enabled some civilizations to survive longer than others. It was only with the development of more consistent fertilization and newer, higher-analysis materials that crop production entered an era where it could reliably feed beyond the family unit but feed the city, and then the whole country. This modern industrial fertilization required fewer people to be devoted to food production so that their efforts could be directed to more secondary and tertiary careers. The growth of the use of fertilizer by over 200% in 40 years has led to an increased scrutiny of its environmental aspect in the early 21st century, and this has led to a revaluation of application procedures and to an increase in research and development of new forms of fertilizer and into ways to change modern fertilizers’ environmental footprints to better steward food production and remedy systems that are off target environmentally. These technologies are sometimes very basic, such as including combinations of elements which help stabilize each other (e.g. sulfur and nitrogen or phosphorus and sulfur). Other technologies include polymer-coating (e.g. slow-release coatings) and impregnatable coatings (e.g. nitrapyrin, NBPT). In other cases, new materials have been developed (e.g. methylated urea) and in yet others progress has come from a mixing of other compounds with the fertilizer (e.g. gypsum to phosphorus fertilizer, or humic acids to nitrogen formulations). Lastly, there has been a rise in the importance of micronutrients as production has increased (e.g. zinc, manganese, and boron) especially as yield levels have increased.
