Water is essential to life and development in terms of both quantity and quality. Water resources continue to face various pressures brought about by climate change, growing population, and increased economic demand for water. Managing this unique and precious resource has become a global challenge. The conflicts over water issues often arise not only among stakeholders facing limited water resources but also from social and political aspects of the design, operation, and management of water supply projects. A fair and sustainable system of sharing water resources, therefore, is one of the greatest challenges we face in the 21st century. In the absence of negotiation and lack of clear property rights, water is a source for human conflicts.
Game theory as strategic analysis has provided powerful tools and been applied to many fields, including water resources management. The basic assumptions of game theory emphasize that rational players who pursue well-defined objectives and assume knowledge of others would accordingly form expectations of other decision makers’ behavior. Hence, game theory is used to predict agents’ behaviors toward fulfilling their own interests during the interactive decision-making process with other agents.
Since the 1950s, game theory has become an important tool for analyzing important aspects of water resource management. Yet despite the rapid increase in the application of game theoretical approaches to water resource management, many challenges remain. The challenges of the early 21st century, including resource constraints, financial instability, inequalities within and between countries, and environmental degradation, present opportunities to address and reach resolutions on how water is governed and managed to ensure that everyone has sufficient access to water.
41-60 of 312 Results
Article
Kim Hang Pham Do
Article
Vic Adamowicz and Diane Dupont
A number of challenges are faced by practitioners seeking to elicit values associated with water in a world of global change. These values are needed to assist in decision-making around the use of water as a country’s key asset. Five different pathways show the complexity of the relationship between global change and environmental valuation of water: a climate change pathway, ecosystem infrastructure pathway, population/demographics pathway, income pathway, and technological change/innovation pathway. The challenges are most acute for water when it is related to ecosystem services since values need to be elicited through the use of non-market survey-based valuation techniques. In addition, environmental valuation will be important to inform the determination of water quality standards associated with different uses of water (drinking, recreation, etc.) and the allocation of resources to provide these different services. Several case studies illustrate issues and solutions. The article concludes with an appreciation of future challenges and opportunities.
Article
Lang Wang and Zong-Liang Yang
The terms “land cover” and “land use” are often used interchangeably, although they have different meanings. Land cover is the biophysical material at the surface of the Earth, whereas land use refers to how people use the land surface. Land use concerns the resources of the land, their products, and benefits, in addition to land management actions and activities. The history of changes in land use has passed through several major stages driven by developments in science and technology and demands for food, fiber, energy, and shelter.
Modern changes in land use have been increasingly affected by anthropogenic activities at a scale and magnitude that have not been seen. These changes in land use are largely driven by population growth, urban expansion, increasing demands for energy and food, changes in diets and lifestyles, and changing socioeconomic conditions. About 70% of the Earth’s ice-free land surface has been altered by changes in land use, and these changes have had environmental impacts worldwide, ranging from effects on the composition of the Earth’s atmosphere and climate to the extensive modification of terrestrial ecosystems, habitats, and biodiversity. A number of different methods have been developed give a thorough understanding of these changes in land use and the multiple effects and feedbacks involved. Earth system observations and models are examples of two crucial technologies, although there are considerable uncertainties in both techniques. Cross-disciplinary collaborations are highly desirable in future studies of land use and management. The goals of mitigating climate change and maintaining sustainability should always be considered before implementing any new land management strategies.
Article
Mental and behavioral disorders account for approximately 7.4% of the global burden of disease, with depression now the world’s leading cause of disability. One in four people in the world will suffer from a mental health problem at some point in their life. City planning and design holds much promise for reducing this burden of disease, and for offering solutions that are affordable, accessible and equitable. Increasingly urban green space is recognized as an important social determinant of health, with the potential to protect mental health – for example, by buffering against life stressors - as well as relieving the symptom severity of specific psychiatric disorders. Pathways linking urban green space with mental wellbeing include the ability of natural stimuli – trees, water, light patterns – to promote ‘involuntary attention’ allowing the brain to disengage and recover from cognitive fatigue. This article brings together evidence of the positive effects of urban green space on common mental health problems (i.e. stress, anxiety, depression) together with evidence of its role in the symptom relief of specific psychiatric disorders, including schizophrenia and psychosis, post-traumatic stress disorder (PTSD), dementia, attention deficit/hyperactivity Disorder (ADHD) and autism. Urban green space is a potential force for building mental health: city planners, urban designers, policy makers and public health professionals need to maximize the opportunities in applying green space strategies for both health prevention and in supporting treatment of mental ill health.
Article
Sander Turnhout and Wessel Ganzevoort
Citizen science can be understood as an approach to scientific research in which volunteer contributors undertake work in one or more phases of the research process. Citizen science projects can be initiated by volunteers or institutional actors (e.g., scientists in academia), and volunteers often work together with professional researchers. In citizen science, participants are not just objects of research (e.g., interviewee or survey respondent) but also research subjects—that is, taking an active role in collecting data, analyzing data sets, contributing to study design, or disseminating results (or combinations of these tasks). Participants may have little background knowledge on the topic under study, or they might be amateur enthusiasts with a great deal of existing expertise. Citizen science projects aim for genuine science outcomes, which can include scientific data sets and publications, new discoveries, or policy or management action.
Although citizen science projects are currently being developed and carried out in a wide variety of scientific fields, including medical biology (e.g., self-monitoring of disease symptoms), environmental science (e.g., monitoring air or water quality), history (e.g., archive transcription), and “citizen social science,” the field of biology especially has a long history of amateur involvement in research. Citizen science in this field often takes the form of collecting data on the natural world and submitting these data to biodiversity databases (e.g., reporting bird observations). In addition to collecting data, citizen scientists take up a large part of taxonomy, describing new species and rearranging, merging, and splitting species groups. Furthermore, citizen scientists are heavily involved in the verification process, checking on observations done by other citizen scientists and giving feedback, acting not only as gatekeepers toward data quality but also as authorities, educating the community.
Biodiversity citizen science projects may involve monitoring of the natural world initiated by communities of natural history enthusiasts, but research institutes in the field of biology and ecology also increasingly mobilize volunteers to collect data about the natural environment. Compared to many other domains in which citizen science is being applied, biodiversity monitoring especially stands out for its long history of amateur involvement in natural history. Because initiating biodiversity citizen science projects will thus often mean that research and policy actors engage with volunteer-driven networks, understanding these networks aids effective and just design of biodiversity citizen science.
Although engaging with these long-standing networks of natural history offers many opportunities, perspectives of professional ecological research and communities of practice can differ markedly. In the current state of affairs, scientific literature shows tensions between volunteers operating in their communities of practice and scientists operating in theirs. Among others, these differences involve the meaning of observations: Whereas in research these are given meaning by gathering them up and statistically analyzing the resulting data sets, within a community of practice observations predominantly reflect human–nature relationships and are shared with expectations of respectful use for the protection of nature. Not only can the meaning of observations differ but also the act of validation can refer to very different activities as well as to different aspects of quality of information. In the community of practice of observers in the field, validation plays an important role in establishing relations of trust and authority within the network, with a strong emphasis on correct observations and volunteers’ motivation for learning and belonging. Conversely, validation in the scientific practice of research concerns the structure of the monitoring protocol and the statistical demands placed on the data.
For scientists and policymakers, respectful cooperation with networks of amateur biodiversity recorders requires taking their perspectives seriously and respecting their way of working and the communities they have built. It also requires citizen science organizers to think carefully about whose questions are being answered. For citizen scientists, understanding the (statistical) needs of scientists and the relevance for policy allows their network to grow through funding and training.
Article
Paolo Inglese and Giuseppe Sortino
In May, every year since 1857, in the great park of Sans-Souci in Potsdam just outside Berlin—a park begun in 1745 by Emperor Frederick II of Hohenzollern and expanded a century later by Frederick William IV—the doors of the great Orangerie open in and a Renaissance-style garden called Sizilianischer Garten is set up. On horse-drawn carriages, large olive and citrus trees are brought outdoors, and are then raised in masters.
For the young European who, in the second half of the 18th century and in the first decades of the following, traveled to Italy to see and study Renaissance culture and the remains of Greek civilization, the citrus species and fruits and groves of southern Italy became the ultimate symbol of beauty and a sort of status symbol of wealth, particularly that of landowners. Nothing is more expressive of the fascination of their fruit than Abu-l-Hasan Ali’s 12th-century writings: “Come on, enjoy your harvested orange: happiness is present when it is present. / Welcome the cheeks of the branches, and welcome the stars of the trees! / It seems that the sky has lavished gold and that the earth has formed some shiny spheres.”
Indeed, Citrus spp. are among the most important crops and consumed fruit worldwide. Their co-evolution due to a millennial agricultural utilization resulted in a complexity of species and cultivated varieties derived by natural or induced mutations, crossing and breeding the “original” species (Citrus medica, Citrus maxima, Citrus reticulate, Fortunella japonica) and their main progenies (C. aurantium, C. sinensis, Citrus limon, Citrus paradisi, Citrus clementina, etc.). Citrus spread from the original tropical and subtropical regions of southeast Asia toward the Mediterranean countries of Europe and North Africa and, after 1492, in the Americas, not to mention South Africa and Australia, where they still have a very important role. Citrus species, wherever they have been cultivated, quickly became the protagonists of the letters and the arts, as well as the markets and gastronomy, and can even be found in religious ceremonies, such as for Feast of Tabernacles (Sukkot). Studies on Citrus botany, cultivation, and utilization have been pursued since the early stages of the fruit’s domestication and grew following their introduction in Europe, the Americas, Africa, and Australia. Citrus research involves many different aspects: such as the study of citrus origin and botanical classification; citrus growing, propagation, and orchard management; citrus fruit quality, utilization and industry; citrus gardening and ornamentals; citrus in arts and manufacturing.
Article
Soil salinity has been causing problems for agriculturists for millennia, primarily in irrigated lands. The importance of salinity issues is increasing, since large areas are affected by irrigation-induced salt accumulation. A wide knowledge base has been collected to better understand the major processes of salt accumulation and choose the right method of mitigation. There are two major types of soil salinity that are distinguished because of different properties and mitigation requirements. The first is caused mostly by the large salt concentration and is called saline soil, typically corresponding to Solonchak soils. The second is caused mainly by the dominance of sodium in the soil solution or on the soil exchange complex. This latter type is called “sodic” soil, corresponding to Solonetz soils. Saline soils have homogeneous soil profiles with relatively good soil structure, and their appropriate mitigation measure is leaching. Naturally sodic soils have markedly different horizons and unfavorable physical properties, such as low permeability, swelling, plasticity when wet, and hardness when dry, and their limitation for agriculture is mitigated typically by applying gypsum. Salinity and sodicity need to be chemically quantified before deciding on the proper management strategy. The most complex management and mitigation of salinized irrigated lands involves modern engineering including calculations of irrigation water rates and reclamation materials, provisions for drainage, and drainage disposal. Mapping-oriented soil classification was developed for naturally saline and sodic soils and inherited the first soil categories introduced more than a century ago, such as Solonchak and Solonetz in most of the total of 24 soil classification systems used currently. USDA Soil Taxonomy is one exception, which uses names composed of formative elements.
Article
Sarah E. Scales, Julia Massi, and Jennifer A. Horney
Climate change is affecting every region of the world and is accelerating at an alarming rate. International efforts for mitigating climate change, like the Paris Agreement, through reductions in greenhouse gases are vital for slowing the global increase in temperatures. However, these mitigation measures will not have immediate impact, so urgent action is needed to address negative impacts currently posed by climate change. Adaptation measures are central to this response now, and will continue to be critical for protecting human health as temperatures rise and climate-related disasters increase in both frequency and severity. To maximize the effectiveness of adaptation measures, the health impacts of disasters should be well-characterized at the global, regional, national, and local levels. Surveillance and early warning systems are vital tools for early identification and warning of hazards and their potential impacts. Increasing global capacity to identify causes of morbidity and mortality directly and indirectly attributable to disasters are in line with the objectives of the Sustainable Development Goals and Bangkok Principles of the Sendai Framework for Disaster Risk Reduction. Both improving data collected in disaster settings and more effectively using that information in real time are central to reducing the human-health impacts of disasters. The human-health impacts of climate change and associated disasters are interrelated. Climate change and commensurate changes in environmental suitability, vector viability, and human migration strongly influence the prevalence and seasonality of infectious and communicable diseases. Both drought and flood contribute to food and water insecurity, leading to a higher prevalence of undernourishment and malnourishment, especially in children. Compromised nutritional status, in conjunction with resulting human migration, leave individuals immunocompromised and populations at a high risk for spread of infectious disease. Extreme heat exposure likewise compromises individuals’ ability to regulate their physiological response to external stressors. Disasters of all classifications can result in exposure to environmental hazards, decrease air quality, and negatively affect mental health. Accordingly, health adaptation measures to climate change must be equally interrelated, addressing needs across disciplines, at both individual and community levels, and incorporating the many facets of the health needs of affected populations.
Article
Ariel R. Angeli, Federico E. Bert, Sandro Díez-Amigo, Yuri Soares, Jaquelina M. Chaij, Gustavo D. Martini, F. Martín Montané, Alejandro Pardo Vegezzi, and Federico Schmidt
During the past two decades, extensive agriculture, particularly soybean production, has progressively replaced other crops in Argentina. This transformation was driven by economic, technological, environmental, and organizational factors, such as the increasing demand for agricultural commodities, technological advances, organizational innovations, and climate fluctuations. The expansion of soybean production has brought a substantial increase in agricultural revenue for Argentina. However, the predominance of soybean cultivation poses significant challenges, such as diminished soil fertility, reduction and increased variability in crop yields, ecological imbalance, increased greenhouse gas (GHG) emissions, and vulnerability to climate change.
Crop rotation, particularly balanced crop rotation, may result in very large positive impacts on soybean yields, especially in unfavorable climatic conditions such as those experienced during the La Niña ENSO phase in Argentina. In addition to this positive impact on agricultural productivity and climate adaptation, in some contexts crop rotation may also contribute to the reduction of GHG emissions, increased input energy efficiency, and improved environmental outcomes.
The 2018 Argentinian Association of Regional Consortia for Agricultural Experimentation and Inter-American Development Bank (AACREA-IADB) Integrated Crop Rotation Database compiled and harmonized the information from agricultural diaries kept by Regional Consortia for Agricultural Experimentation (CREA) members in Argentina from 1998 to 2016. This new consolidated data set has replaced previous regional templates, and it is expected to continue to be expanded with new information periodically, offering opportunities for further research on the impact of crop rotation on climate adaptation and on other topics in agricultural and environmental economics.
Article
Laura Pereira
Confidence in the projected impacts of climate change on agricultural systems has increased substantially since the first Intergovernmental Panel on Climate Change (IPCC) reports. In Africa, much work has gone into downscaling global climate models to understand regional impacts, but there remains a dearth of local level understanding of impacts and communities’ capacity to adapt. It is well understood that Africa is vulnerable to climate change, not only because of its high exposure to climate change, but also because many African communities lack the capacity to respond or adapt to the impacts of climate change. Warming trends have already become evident across the continent, and it is likely that the continent’s 2000 mean annual temperature change will exceed +2°C by 2100. Added to this warming trend, changes in precipitation patterns are also of concern: Even if rainfall remains constant, due to increasing temperatures, existing water stress will be amplified, putting even more pressure on agricultural systems, especially in semiarid areas. In general, high temperatures and changes in rainfall patterns are likely to reduce cereal crop productivity, and new evidence is emerging that high-value perennial crops will also be negatively impacted by rising temperatures. Pressures from pests, weeds, and diseases are also expected to increase, with detrimental effects on crops and livestock.
Much of African agriculture’s vulnerability to climate change lies in the fact that its agricultural systems remain largely rain-fed and underdeveloped, as the majority of Africa’s farmers are small-scale farmers with few financial resources, limited access to infrastructure, and disparate access to information. At the same time, as these systems are highly reliant on their environment, and farmers are dependent on farming for their livelihoods, their diversity, context specificity, and the existence of generations of traditional knowledge offer elements of resilience in the face of climate change. Overall, however, the combination of climatic and nonclimatic drivers and stressors will exacerbate the vulnerability of Africa’s agricultural systems to climate change, but the impacts will not be universally felt. Climate change will impact farmers and their agricultural systems in different ways, and adapting to these impacts will need to be context-specific.
Current adaptation efforts on the continent are increasing across the continent, but it is expected that in the long term these will be insufficient in enabling communities to cope with the changes due to longer-term climate change. African famers are increasingly adopting a variety of conservation and agroecological practices such as agroforestry, contouring, terracing, mulching, and no-till. These practices have the twin benefits of lowering carbon emissions while adapting to climate change as well as broadening the sources of livelihoods for poor farmers, but there are constraints to their widespread adoption. These challenges vary from insecure land tenure to difficulties with knowledge-sharing.
While African agriculture faces exposure to climate change as well as broader socioeconomic and political challenges, many of its diverse agricultural systems remain resilient. As the continent with the highest population growth rate, rapid urbanization trends, and rising GDP in many countries, Africa’s agricultural systems will need to become adaptive to more than just climate change as the uncertainties of the 21st century unfold.
Article
Marc Dourojeanni
In 1945 the Amazon biome was almost intact. Marks of ancient cultural developments in Andean and lowland Amazon had cicatrized and the impacts of rubber and more recent resources exploitation were reversible. Very few roads existed, and only on the Amazon’s periphery. However, from the 1950s, but especially in the 1960s, Brazil and some Andean countries launched ambitious road-building and colonization processes. Amazon occupation heavily intensified in the 1970s when forest losses began to raise worldwide concern. More roads continued to be built at a geometrically growing pace in every following decade, multiplying correlated deforestation and forest degradation. A no-return point was reached when interoceanic roads crossed the Brazilian-Andean border in the 2000s, exposing remaining safe havens for indigenous people and nature. It is commonly estimated that today no less than 18% of the forest has been substituted by agriculture and that over 60% of that remaining has been significantly degraded.
Theories regarding the importance of biogeochemical cycles have been developed since the 1970s. The confirmation of the role of the Amazon as a carbon sink added some international pressure for its protection. But, in general, the many scientific discoveries regarding the Amazon have not helped to improve its conservation. Instead, a combination of new agricultural technologies, anthropocentric philosophies, and economic changes strongly promoted forest clearing.
Since the 1980s and as of today Amazon conservation efforts have been increasingly diversified, covering five theoretically complementary strategies: (a) more, larger, and better-managed protected areas; (b) more and larger indigenous territories; (c) a series of “sustainable-use” options such as “community-based conservation,” sustainable forestry, and agroforestry; (d) financing of conservation through debt swaps and climate change’s related financial mechanisms; and (e) better legislation and monitoring. Only five small protected areas have existed in the Amazon since the early 1960s but, responding to the road-building boom of the 1970s, several larger patches aiming at conserving viable samples of biological diversity were set aside, principally in Brazil and Peru. Today around 22% of the Amazon is protected but almost half of such areas correspond to categories that allow human presence and resources exploitation, and there is no effective management. Another 28% or more pertains to indigenous people who may or may not conserve the forest. Both types of areas together cover over 45% of the Amazon. None of the strategies, either alone or in conjunction, have fully achieved their objectives, while development pressures and threats multiply as roads and deforestation continue relentlessly, with increasing funding by multilateral and national banks and due to the influence of transnational enterprises.
The future is likely to see unprecedented agriculture expansion and corresponding intensification of deforestation and forest degradation even in protected areas and indigenous land. Additionally, the upper portion of the Amazon basin will be impacted by new, larger hydraulic works. Mining, formal as well as illegal, will increase and spread. Policymakers of Amazon countries still view the region as an area in which to expand conventional development while the South American population continues to be mostly indifferent to Amazon conservation.
Article
John A. Sorrentino
Carbon has been part of the Earth since its beginning, and the carbon cycle is well understood. However, its abundance in the atmosphere has become a problem. Those who propose solutions in decentralized market economies often prefer economic incentives to direct government regulation. Carbon cap-and-trade programs and carbon tax programs are the prime candidates to rein in emissions by altering the economic conditions under which producers and consumers make decisions. Under ideal conditions with full information, they can seamlessly remove the distortion caused by the negative externality and increase a society’s welfare. This distortion is caused by overproduction and underpricing of carbon-related goods and services. The ideal level of emissions would be set under cap-and-trade, or be the outcome of an ideally set carbon tax. The ideal price of carbon permits would result from demand generated by government decree meeting an ideal fixed supply set by the government. The economic benefit of using the ideal carbon tax or the ideal permit price occurs because heterogeneous decision-makers will conceptually reduce emissions to the level that equates their marginal (incremental) emissions-reduction cost to the tax or permit price. When applying the theory to the real world, ideal conditions with full information do not exist. The economically efficient levels of emissions, the carbon tax, and the permit price cannot be categorically determined. The targeted level of emissions is often proposed by non-economists. The spatial extent and time span of the emissions target need to be considered. The carbon tax is bound to be somewhat speculative, which does not bode well for private-sector decision-makers who have to adjust their behavior, and for the achievement of a particular emissions target. The permit price depends on how permits are initially distributed and how well the permit market is designed. The effectiveness of either program is tied to monitoring and enforcement. Social justice considerations in the operation of tax programs often include the condition that they be revenue-neutral. This is more complicated in the permit scheme as much activity after the initial phase is among the emitters themselves.
Based on global measurement of greenhouse gases, several models have been created that attempt to explain how emissions transform into concentrations, how concentrations imply radiative forcing and global warming potential, how the latter cause ecological and economic impacts, and how mitigation and/or adaptation can influence these impacts. Scenarios of the uncertain future continue to be generated under myriad assumptions in the quest for the most reliable. Several institutions have worked to engender sustained cooperation among the parties of the “global commons.” The balance of theory and empirical observation is intended to generate normative and positive policy recommendations. Cap-and-trade and carbon tax programs have been designed and/or implemented by various countries and subnational jurisdictions with the hope of reducing carbon-related emissions. Many analysts have declared that the global human society will reach a “tipping point” in the 21st century, with irreversible trends that will alter life on Earth in significant ways.
Article
Adaptation of cropping systems to weather uncertainty and climate change is essential for resilient food production and long-term food security. Changes in climate result in substantial temporal modifications of cropping conditions, and rainfall and temperature patterns vary greatly with location. These challenges come at a time when global human population and demand for food are both increasing, and it appears to be difficult to find ways to satisfy growing needs with conventional systems of production. Agriculture in the future will need to feature greater biodiversity of crop species and appropriate design and management of cropping and integrated crop/animal systems. More diverse and longer-cycle crop rotations will need to combine sequences of annual row crops such as maize and soybean with close-drilled cereals, shallow-rooted with deep-rooted crops, summer crops with winter crops, and annuals with perennials in the same fields. Resilience to unpredictable weather will also depend on intercropping, with the creative arrangement of multiple interacting crop species to diversify the field and the landscape. Other multiple-cropping systems and strategies to integrate animals and crops will make more efficient use of natural resources and applied inputs; these include systems such as permaculture, agroforestry, and alley cropping. Future systems will be spatially diverse and adapted to specific fields, soil conditions, and unique agroecozones. Production resilience will be achieved by planting diverse combinations of species together in the same field, and economic resilience through producing a range of products that can be marketed through different channels. The creation of local food webs will be more appropriate in the future, as contrasted with the dominance of global food chains today. Materials considered “waste” from the food system, including human urine and feces, will become valuable resources to be cycled back into the natural environment and into food production. Due to the increasing scarcity of fertile land, the negative contributions of chemicals to environmental pollution, the costs of fossil fuels, and the potential for the economic and political disruption of supply chains, future systems will increasingly need to be local in character while still achieving adaptation to the most favorable conditions for each system and location. It is essential that biologically and economically resilient systems become productive and profitable, as well as environmentally sound and socially equitable, in order to contribute to stability of food production, security of the food supply, and food sovereignty, to the extent that this is possible. The food system cannot continue along the lines of “business as usual,” and its path will need to radically diverge from the recognized trends toward specialization and globalization of the early 21st century. The goal needs to shift from exploitation and short-term profits to conservation of resources, greater equity in distribution of benefits, and resilience in food supply, even with global climate change.
Article
Faisal Nadeem, Ahmad Nawaz, and Muhammad Farooq
Planned crop rotation offers a pragmatic option to improve soil fertility, manage insect pests and diseases, and offset the emission of greenhouse gases. The inclusion of legume crops in crop rotations helps to reduce the use of external nitrogen inputs for legumes and other crops because legumes may fix the atmospheric nitrogen. This also helps to reduce the environmental pollution caused by volatilization and leaching of applied nitrogen. The inclusion of allelopathic crops in rotation may be useful to suppress noxious weeds due to release of the allelochemicals in the rhizosphere. The rotation of tap-rooted crops with shallow rooted crops may result in efficient and productive use of nutrient resources and conservation of soil moisture. Continuous monoculture systems may cause the loss of biodiversity. Land fallowing is an efficient agricultural management technique mostly practiced in arid regions to capture rainwater and store it in the soil profile for later use in crop production. During fallowing, tillage operations are practiced to enhance moisture conservation in the soil. Keeping soil fallow for a season or more restores soil fertility through nutrient deposits; increases organic matter, microbial carbon, and soil microbial diversity; and improves the soil’s physical properties, including aggregation stability and reduced soil compaction due to decreased traffic. In addition, fallowing of land provides biological means of pest (weeds and insects) control by disrupting the life cycle of pests and decreasing reliance on pesticides. Land fallowing can help offset the emission of greenhouse gases from agricultural fields by reducing traffic and increasing carbon sequestration within the soil. Summer fallowing may help to preserve moisture in diverse soil types in the rainfed regions of the world, although it may reduce the carbon sequestration potential of soils over the long term. Energy resources are decreasing, and the inclusion of energy crops in crop rotation may be highly beneficial. Many of the processes, factors, and mechanisms involved in crop rotation and land fallowing are poorly understood and require further investigation.
Article
Emerson Nafziger
Corn ranks first among crops in quantity produced globally, owing to its high yield and to its value as a food for humans and domestic animals. While its water-use efficiency is high compared to that of other crops, the production of high corn yields requires a great deal of water; the availability of water largely determines where the crop is grown. As a high-yielding grass species, corn also requires a substantial supply of nutrients (especially nitrogen) from external sources, including manufactured fertilizers and organic materials such as animal or green manures. This, along with the need to manage soils, weeds, insects, and diseases, makes corn production environmentally consequential.
Corn captures large quantities of sunlight energy through photosynthesis, but its production requires large external inputs of energy, coming mostly (in mechanized production) from fossil fuels. So even though the crop’s high yields moderates the environmental cost per unit of grain produced, minimizing the external environmental consequences of large-scale corn production is an important goal in the quest for greater sustainability of production of this important crop.
Article
Shu Ting Chang and Solomon P. Wasser
The word mushroom may mean different things to different people in different countries. Specialist studies on the value of mushrooms and their products should have a clear definition of the term mushroom. In a broad sense, “Mushroom is a distinctive fruiting body of a macrofungus, which produce spores that can be either epigeous or hypogeous and large enough to be seen with the naked eye and to be picked by hand.” Thus, mushrooms need not be members of the group Basidiomycetes, as commonly associated, nor aerial, nor fleshy, nor edible. This definition is not perfect, but it has been accepted as a workable term to estimate the number of mushrooms on Earth (approximately 16,000 species according to the rules of International Code of Nomenclature). The most cultivated mushrooms are saprophytes and are heterotrophic for carbon compounds. Even though their cells have walls, they are devoid of chlorophyll and cannot perform photosynthesis. They are also devoid of vascular xylem and phloem. Furthermore, their cell walls contain chitin, which also occurs in the exoskeleton of insects and other arthropods. They absorb O2 and release CO2. In fact, they may be functionally more closely related to animal cells than plants. However, they are sufficiently distinct both from plants and animals and belong to a separate group in the Fungi Kingdom. They rise up from lignocellulosic wastes: yet, they become bountiful and nourishing. Mushrooms can greatly benefit environmental conditions. They biosynthesize their own food from agricultural crop residues, which, like solar energy, are readily available; otherwise, their byproducts and wastes would cause health hazards. The spent compost/substrate could be used to grow other species of mushrooms, as fodder for livestock, as a soil conditioner and fertilizer, and in environmental bioremediation. The cultivation of mushrooms dates back many centuries; Auricularia auricula-judae, Lentinula edodes, and Agaricus bisporus have, for example, been cultivated since 600 ad, 1100 ad, and 1650 ad, respectively. During the last three decades, there has been a dramatic increase in the interest, popularity, and production of mushrooms through farming worldwide. The cultivation methods can involve a relatively simple farming activity, as with Volvariella volvacea and Pleurotus pulmonarius var. stechangii (=P. sajor-caju), or a high-technology industry, as with Agaricus bisporus, Flammulina velutipes, and Hypsizygus marmoreus. In each case, however, continuous production of successful crops requires both practical experience and scientific knowledge.
Mushrooms can be used as food, tonics, medicines, cosmeceuticals, and as natural biocontrol agents in plant protection with insecticidal, fungicidal, bactericidal, herbicidal, nematocidal, and antiphytoviral activities. The multidimensional nature of the global mushroom cultivation industry, its role in addressing critical issues faced by humankind, and its positive contributions are presented. Furthermore, mushrooms can serve as agents for promoting equitable economic growth in society. Since the lignocellulose wastes are available in every corner of the world, they can be properly used in the cultivation of mushrooms, and therefore could pilot a so-called white agricultural revolution in less developed countries and in the world at large. Mushrooms demonstrate a great impact on agriculture and the environment, and they have great potential for generating a great socio-economic impact in human welfare on local, national, and global levels.
Article
Reiner Wassmann
Assessing the environmental footprints of modern agriculture requires a balanced approach that sets the obviously negative effects (e.g., incidents with excessive use of inputs) against benefits stemming from increased resource use efficiencies. In the case of rice production, the regular flooding of fields comprises a distinctive feature, as compared to other crops, which directly or indirectly affects diverse impacts on the environment. In the regional context of Southeast Asia, rice production is characterized by dynamic changes in terms of crop management practices, so that environmental footprints can only be assessed from time-dependent developments rather than from a static view. The key for the Green Revolution in rice was the introduction of high-yielding varieties in combination with a sufficient water and nutrient supply as well as pest management. More recently, mechanization has evolved as a major trend in modern rice production. Mechanization has diverse environmental impacts and may also be instrumental in tackling the most drastic pollution source from rice production, namely, open field burning of straw. As modernization of rice production is imperative for future food supplies, there is scope for developing sustainable and high-yielding rice production systems by capitalizing on the positive aspects of modernization from a local to a global scale.
Article
Peter Shewry
Wheat is the most widely grown food crop in the world and the dominant staple crop in temperate countries where it contributes between about 20% and 50% of the total energy intake. About 95% of the wheat grown is hexaploid bread wheat, with tetraploid durum wheat being grown in the hot dry Mediterranean climate and very small volumes of ancient species. About 80% of the dry weight of the mature grain is starchy endosperm. This is the major grain storage tissue, which is separated by milling to give white flour, the outer layers and germ together forming the bran. However, white flour and bran differ significantly in their compositions, with white flour being rich in starch (about 80% dry wt) and protein (about 10% dry wt) and the bran rich in fiber, minerals, vitamins, and phytochemicals.
Most of the wheat consumed by humankind is in the form of bread, noodles, pasta, and other processed foods, and the quality for processing is determined by two major characteristics: the grain texture (hardness) and the viscoelastic properties conferred to dough by the gluten proteins.
In addition to being a source of energy, wheat also contributes protein and a range of other essential and beneficial components, particularly dietary fiber. However, because most of these components are concentrated in the bran, it is important to increase the consumption of whole grain products or to improve the composition of white flour. Although there is concern among consumers about possible adverse effects of consuming wheat products on health, these are unlikely to affect more than a small proportion of the population, and wheat should form part of a healthy balanced diet for the vast majority.
Article
Mainaak Mukhopadhyay and Tapan Kumar Mondal
Tea, the globally admired, non-alcoholic, caffeine-containing beverage, is manufactured from the tender leaves of the tea [Camellia sinensis (L.)] plant. It is basically a woody, perennial crop with a lifespan of more than 100 years. Cultivated tea plants are natural hybrids of the three major taxa or species, China, Assam (Indian), or Cambod (southern) hybrids based on the morphological characters (principally leaf size). Planting materials are either seedlings (10–18 months old) developed from either hybrid, polyclonal, or biclonal seeds, or clonal cuttings developed from single-leaf nodal cuttings of elite genotypes. Plants are forced to remain in the vegetative stage as bushes by following cultural practices like centering, pruning, and plucking, and they are harvested generally from the second year onward at regular intervals of 7–10 days in the tropics and subtropics, with up to 60 years as the economic lifespan. Originally, the Chinese were the first to use tea as a medicinal beverage, around 2000 years ago, and today, around half of the world’s population drink tea. It is primarily consumed as black tea (fermented tea), although green tea (non-fermented) and oolong tea (semifermented) are also consumed in many countries. Tea is also used as vegetables such as “leppet tea” in Burma and “meing tea” in Thailand.
Green tea has extraordinary antioxidant properties, and black tea plays a positive role in treating cardiovascular ailments. Tea in general has considerable therapeutic value and can cure many diseases. Global tea production (black, green, and instant) has increased significantly during the past few years. China, as the world’s largest tea producer, accounts for more than 38% of the total global production of made tea [i.e. ready to drink tea] annually, while production in India, the second-largest producer. India recorded total production of 1233.14 million kg made tea during 2015–2016, which is the highest ever production so far.
Since it is an intensive monoculture, tea cultivation has environmental impacts. Application of weedicides, pesticides, and inorganic fertilizers creates environmental hazards. Meanwhile, insecticides often eliminate the fauna of a vast tract of land. Soil degradation is an additional concern because the incessant use of fertilizers and herbicides compound soil erosion. Apart from those issues, chemical runoff into bodies of water can also create problems. Finally, during tea manufacturing, fossil fuel is used to dry the processed leaves, which also increases environmental pollution.
Article
Christopher Lu
Dairy has intertwined with human society since the beginning of civilization. It evolves from art in ancient society to science in the modern world. Its roles in nutrition and health are underscored by the continuous increase in global consumption. Milk production increased by almost 50% in just the past quarter century alone. Population growth, income rise, nutritional awareness, and science and technology advancement contributed to a continuous trend of increased milk production and consumption globally. With a fourfold increase in milk production per cow since the 1940s, the contemporary dairy industry produces more milk with fewer cows, and consumes less feed and water per liter of milk produced. The dairy sector is diversified, as people from a wider geographical distribution are consuming milk, from cattle to species such as buffalo, goat, sheep, and camel. The dairy industry continues to experience structural changes that impact society, economy, and environment. Organic dairy emerged in the 1990s as consumers increasingly began viewing it as an appropriate way of both farming and rural living. Animal welfare, environmental preservation, product safety, and health benefit are important considerations in consuming and producing organic dairy products. Large dairy operations have encountered many environmental issues related to elevated greenhouse gas emissions. Dairy cattle are second only to beef cattle as the largest livestock contributors in methane emission. Disparity in greenhouse gas emissions per dairy animal among geographical regions can be attributed to production efficiency. Although a number of scientific advancements have implications in the inhibition of methanogenesis, improvements in production efficiency through feeding, nutrition, genetic selection, and management remain promising for the mitigation of greenhouse gas emissions from dairy animals. This article describes the trends in milk production and consumption, the debates over the role of milk in human nutrition, the global outlook of organic dairy, the abatement of greenhouse gas emissions from dairy animals, as well as scientific and technological developments in nutrition, genetics, reproduction, and management in the dairy sector.
