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The Qanat System of Iran and the Maghreb  

Ahmad Abbasnejad and Behnam Abbasnejad

A qanat is a kind of subterranean horizontal tunnel and usually excavated in soft sediments. It conducts groundwater to the surface at its emerging point. In addition to the tunnel, each qanat contains anywhere from several to hundreds of vertical wells for removal of dig materials and ventilation of the tunnel. These wells get increasingly deep until the deepest and last one, which is known as the mother well. According to the literature, qanat was first developed around 800 to 1000 bc in northwest of Iran and afterward was utilized in many other countries in Asia, Africa, southern Europe, and even (through independent invention) in the Americas. The areas utilizing the qanat have three characteristics in common: the shortage of surficial water (streams) indicating an arid or semiarid climate; suitable topographical slopes that help conduct groundwater to the surface for a distance by a gently sloping tunnel (qanat); and the presence of unconsolidated sediments (usually alluvial) that both act as subsurface reservoirs and as material that can be easily excavated using primitive tools. In another words, dry areas with mountain-plain topography, alluvial fans, and stream beds (wadis) are suitable for digging qanats. Major parts of Iran and some parts of the Maghreb have such conditions. This is why these two regions have been somewhat dependent on qanats for their water supply. Although the invention of qanats helped human settlement and welfare in drier countries, it had some negative impacts. The presence of humans due to qanats directly impacted the wildlife and vegetation cover of those areas. And in some cases, changes in the groundwater regime caused wilting and drying because of limited water resources for plants and wildlife. The history of qanat development may be viewed as undergoing three major stages in the dry zones of Iran and the Maghreb, as well as in many other countries where they are present. During the first stage, from 1,000 to 2,000 years after their introduction (depending upon the region) qanats rapidly proliferated as technology spread to new areas. During the second stage, new qanat construction halted, as they had been developed in almost all suitable areas. In the third stage, beginning in some places in the early 20th century, such factors as increasing demand for groundwater, technical developments in water well drilling, and problems with qanat maintenance and urban sprawl caused many qanats to dry out; their numbers in operation have dropped. This decline will continue with varying rates in different countries. Unfortunately, the rate of decline in Iran, the home country of qanats, is more than many other places. This is mainly due to mismanagement.

Article

The Science of Agroecology  

Juha Helenius, Alexander Wezel, and Charles A. Francis

Agroecology can be defined as scientific research on ecological sustainability of food systems. In addressing food production and consumption systems in their entirety, the focus of agroecology is on interactions and processes that are relevant for transitioning and maintaining ecological, economic, political, and social-cultural sustainability. As a field of sustainability science, agroecology explores agriculture and food with explicit linkages to two other widespread interpretations of the concept of agroecology: environmentally sound farming practices and social movements for food security and food sovereignty. In the study of agroecology as science, both farming practices and social movements emerge as integrated components of agroecological research and development. In the context of agroecology, the concept of ecology refers not only to the science of ecology as biological research but also to environmental and social sciences with research on social systems as integrated social and ecological systems. In agroecological theory, all these three are merged so that agroecology can broadly be defined as “human food ecology” or “the ecology of food systems.” Since the last decades of the 20th century many developments have led to an increased emphasis on agroecology in universities, nonprofit organizations, movements, government programs, and the United Nations. All of these have raised a growing attention to ecological, environmental, and social dimensions of farming and food, and to the question of how to make the transition to sustainable farming and food systems. One part of the foundation of agroecology was built during the 1960s when ecologically oriented environmental research on agriculture emerged as the era of optimism about component research began to erode. Largely, this took place as a reaction to unexpected and unwanted ecological and social consequences of the Green Revolution, a post–World War II scaling-up, chemicalization, and mechanization of agriculture. Another part of the foundation was a nongovernmental movement among thoughtful farmers wanting to develop sustainable and more ecological/organic ways of production and the demand by consumers for such food products. Finally, a greater societal acceptance, demand for research and education, and public funding for not only environmental ecology but also for wider sustainability in food and agriculture was ignited by an almost sudden high-level political awakening to the need for sustainable development by the end of 1980s. Agroecology as science evolved from early studies on agricultural ecosystems, from research agendas for environmentally sound farming practices, and from concerns about addressing wider sustainability; all these shared several forms of systems thinking. In universities and research institutions, agroecologists most often work in faculties of food and agriculture. They share resources and projects among scientists having disciplinary backgrounds in genetics (breeding of plants and animals), physiology (crop science, animal husbandry, human nutrition), microbiology or entomology (crop protection), chemistry and physics (soil science, agricultural and food chemistry, agricultural and food technology), economics (of agriculture and food systems), marketing, behavioral sciences (consumer studies), and policy research (agricultural and food policy). While agroecologists clearly have a mandate to address ecology of farmland, its biodiversity, and ecosystem services, one of the greatest added values from agroecology in research communities comes from its wider systems approach. Agroecologists complement reductionist research programs where scientists seek more detailed understanding of detail and mechanisms and put these into context by developing a broader appreciation of the whole. Those in agroecology integrate results from disciplinary research and increase relevance and adoption by introducing transdisciplinarity, co-creation of information and practices, together with other actors in the system. Agroecology is the field in sustainability science that is devoted to food system transformation and resilience. Agroecology uses the concept of “agroecosystem” in broad ecological and social terms and uses these at multiple scales, from fields to farms to farming landscapes and regions. Food systems depend on functioning agroecosystems as one of their subsystems, and all the subsystems of a food system interact through positive and negative feedbacks, in their complex biophysical, sociocultural, and economic dimensions. In embracing wholeness and connectivity, proponents of agroecology focus on the uniqueness of each place and food system, as well as solutions appropriate to their resources and constraints.

Article

Tomatoes: A Model Crop of Solanaceous Plants  

Raheel Anwar, Tahira Fatima, and Autar K. Mattoo

The modern-day cultivated and highly consumed tomato has come a long way from its ancestor(s), which were in the wild and not palatable. Breeding strategies made the difference in making desirable food, including tomato, available for human consumption. However, like other horticultural produce, the shelf life of tomato is short, which results in losses that can reach almost 50% of the produce, more so in developing countries than in countries with advanced technologies and better infrastructure. Food security concerns are real, especially taking into consideration that the population explosion anticipated by 2050 will require more food production and the production of more nutritious food, which applies as much to the tomato crop as the other crops. Today’s consumer has become aware and is looking for nutritious foods for a healthful and long life. Little was done until recently to generate nutritionally enhanced produce including fruits/vegetables. Also, extreme environments add to plant stress and impact yield and nutritional quality of produce. Recent developments in understandings of the plant/fruit genetics and progress made in developing genetic engineering technologies, including the use of CRISPR-Cas9, raise hopes that a better tomato with a high dose of nutrition and longer-lasting quality will become a reality.

Article

Ancient and Traditional Agriculture, Pastoralism, and Agricultural Societies in Sub-Saharan Africa  

Andrew B. Smith

African domesticated animals, with the exception of the donkey, all came from the Near East. Some 8,000 years ago cattle, sheep, and goats came south to the Sahara which was much wetter than today. Pastoralism was an off-shoot of grain agriculture in the Near East, and those herders immigrating brought with them techniques of harvesting wild grains. With increasing aridity as the Saharan environment dried up around 5000 years ago, the herders began to control and manipulate their stands resulting in millet and sorghum domestication in the Sahel Zone, south of the Sahara. Pearl millet expanded to the south and was taken up by Bantu-speaking Iron Age farmers in the savanna areas of West Africa and then spread around the tropical forest into East Africa by 3000 b.p. As the Sahara dried up and the tsetse belts retreated, sheep and cattle also moved south. They expanded into East Africa via a tsetse-free environment of the Ethiopian highlands arriving around 4000 b.p. It took around 1000 years for the pastoralists to adapt to other epizootic diseases rife in this part of the continent before they could expand throughout the grasslands of Kenya and Tanzania. Thus, East Africa was a socially complex place 3000 years ago, with indigenous hunters, herders and farmers. This put pressure on pastoral use of the environment, so using another tsetse-free corridor from Tanzania, through Zambia to the northern Kalahari, then on to the Western Cape, herders moved to southern Africa, arriving 2000b.p. They were followed to the eastern part of South Africa by Bantu-speaking agro-pastoralists 1600 years ago who were able to use the summer rainfall area for their sorghum and millet crops. Control and manipulation of African indigenous plants of the forest regions probably has a long history from use by hunter-gatherers, but information on this is constrained by archaeological evidence, which is poor in tropical environments due to poor preservation. Evidence for early palm oil domestication has been found in Ghana dated to around 2550b.p. Several African indigenous plants are still widely used, such as yams, but the plant which has spread most widely throughout the world is coffee, originally from Ethiopia. Alien plants, such as maize, potatoes and Asian rice have displaced indigenous plants over much of Africa.

Article

Vermiculture in Greenhouse Plants, Field Crop Production, and Hydroponics  

Norman Q. Arancon and Zachary Solarte

Vermiculture is the art, science, and industry of raising earthworms for baits, feeds, and composting of organic wastes. Composting through the action of earthworms and microogranisms is commonly referred to as vermicomposting. Vermiculture is an art because the technology of raising earthworms requires a comprehensive understanding of the basic requirements for growing earthworms in order to design the space and the system by which organic wastes can be processed efficiently and successfully. It is a science because the technology requires a critical understanding and consideration of the climatic requirements, nutritional needs, growth cycles, taxonomy, and species of earthworms suitable for vermicomposting in order to develop a working system that supports earthworm populations to process successfully the intended organic wastes. The nature of the organic wastes also needs to be taken into careful consideration, especially its composition, size, moisture content, and nutritional value, which will eventually determine the overall quality of the vermicomposts produced. The quality of organic wastes also determines the ability of the earthworms to consume and process them, and the rate by which they turn these wastes into valuable organic amendments. The science of vermiculture extends beyond raising earthworms. There are several lines of evidence that vermicomposts affect plant growth significantly. Vermiculture is an industry because it has evolved from a basic household bin technology to commercially scaled systems in which economic activities emanate from the cost and value of obtaining raw materials, the building of systems, and the utilization and marketing of the products, be they in solid or aqueous extract forms. Economic returns are carefully valued from the production phase to its final utilization as an organic amendment for crops. The discussion revolves around the development of vermiculture as an art, a science, and an industry. It traces the early development of vermicomposting, which was used to manage organic wastes that were considered environmentally hazardous when disposed of improperly. It also presents the vermicomposting process, including its basic requirements, technology involved, and product characteristics, both in solid form and as a liquid extract. Research reports from different sources on the performance of the products are also provided. The discussion attempts to elucidate the mechanisms involved in plant growth and yield promotion and the suppression of pests and diseases. Certain limitations and challenges that the technology faces are presented as well.

Article

Water as a Merit Good  

Michael Hanemann and Dale Whittington

In economics, a merit good is a good which it is judged that an individual or group of individuals should have (at least up to a certain quantity) on the basis of some concept of need, rather than on the basis of ability or willingness to pay. Examples include public elementary education and free hospitals for the poor alongside access to safe, affordable, and reliable water and sanitation. Exactly how a merit good is provided can be subjected to an economic test, but not whether the merit good should be provided. While there are some overlaps in application, the concept of a merit good is distinct from other economic concepts: A merit good may or may not be a public good, and it may or may not involve an externality. However, water and sanitation infrastructure may indeed be viewed as a form of social overhead capital. A merit good is an economic concept; the human right is an ethical concept—and, sometimes, a legal concept. That said, the concept of a merit good and the judgment that a particular item is a merit good clearly have an ethical component. If one accepts the existence of a human right to water and sanitation, that could certainly motivate a government decision to make the provision of water and sanitation a merit good. Even if a commodity is deemed to be a merit good, that still leaves open questions: To which group of people should it be provided as a merit good? In what quantity should it be provided? At what price, if any? By whom should it be provided? And how should the cost be funded?

Article

Water Security  

Claudia Sadoff, David Grey, and Edoardo Borgomeo

Water security has emerged in the 21st century as a powerful construct to frame the water objectives and goals of human society and to support and guide local to global water policy and management. Water security can be described as the fundamental societal goal of water policy and management. This article reviews the concept of water security, explaining the differences between water security and other approaches used to conceptualize the water-related challenges facing society and ecosystems and describing some of the actions needed to achieve water security. Achieving water security requires addressing two fundamental challenges at all scales: enhancing water’s productive contributions to human and ecosystems’ well-being, livelihoods and development, and minimizing water’s destructive impacts on societies, economies, and ecosystems resulting, for example, from too much (flood), too little (drought) or poor quality (polluted) water.

Article

Water User Associations and Collective Action in Irrigation and Drainage  

Bryan Bruns

If there is too little or too much water, farmers may be able to work together to control water and grow more food. Even before the rise of cities and states, people living in ancient settlements cooperated to create better growing conditions for useful plants and animals by diverting, retaining, or draining water. Local collective action by farmers continued to play a major role in managing water for agriculture, including in later times and places when rulers sometimes also organized construction of dams, dikes, and canals. Comparative research on long-lasting irrigation communities and local governance of natural resources has found immense diversity in management rules tailored to the variety of local conditions. Within this diversity, Elinor Ostrom identified shared principles of institutional design: clear social and physical boundaries; fit between rules and local conditions, including proportionality in sharing costs and benefits; user participation in modifying rules; monitoring by users or those accountable to them; graduated sanctions to enforce rules; low-cost conflict resolution; government tolerance or support for self-governance; and nested organizations. During the 19th and 20th centuries, centralized bureaucracies constructed many large irrigation schemes. Farmers were typically expected to handle local operation and maintenance and comply with centralized management. Postcolonial international development finance for irrigation and drainage systems usually flowed through national bureaucracies, strengthening top-down control of infrastructure and water management. Pilot projects in the 1970s in the Philippines and Sri Lanka inspired internationally funded efforts to promote participatory irrigation management in many countries. More ambitious reforms for transfer of irrigation management to water user associations (WUAs) drew on examples in Colombia, Mexico, Turkey, and elsewhere. These reforms have shown the feasibility in some cases of changing policies and practices to involve irrigators more closely in decisions about design, construction, and some aspects of operation and maintenance, including cooperation in scheme-level co-management. However, WUAs and associated institutional reforms are clearly not panaceas and have diverse results depending on context and on contingencies of implementation. Areas of mixed or limited impact and for potential improvement include performance in delivering water; maintaining infrastructure; mobilizing local resources; sustaining organizations after project interventions; and enhancing social inclusion and equity in terms of multiple uses of water, gender, age, ethnicity, poverty, land tenure, and other social differences. Cooperation in managing water for agriculture can contribute to coping with present and future challenges, including growing more food to meet rising demand; competition for water between agriculture, industry, cities, and the environment; increasing drought, flood, and temperatures due to climate change; social and economic shifts in rural areas, including outmigration and diversification of livelihoods; and the pursuit of environmental sustainability.

Article

Well Construction, Cones of Depression, and Groundwater Sharing Approaches  

Fidel Ribera Urenda

The importance of groundwater has become particularly evident in the late 20th and early 21st centuries due to its increased use in many human activities. In this time frame, vertical wells have emerged as the most common, effective, and controlled system for obtaining water from aquifers, replacing other techniques such as drains and spring catchments. One negative effect of well abstraction is the generation of an inverted, conically shaped depression around the well, which grows as water is pumped and can negatively affect water quantity and quality in the aquifer. An increase in the abstraction rate of a specific well or, as is more common, an uncontrolled increase of the number of active wells in an area, could lead to overexploitation of the aquifer’s long-term groundwater reserves and, in some specific contexts, impact water quality. Major examples can be observed in arid or semi-arid coastal areas around the world that experience a high volume of tourism, where aquifers hydraulically connected with the sea are overexploited. In most of these areas, an excessive abstraction rate causes seawater to penetrate the inland part of the aquifer. This is known as marine intrusion. Another typical example of undesirable groundwater management can be found in many areas of intensive agricultural production. Excessive use of fertilizer is associated with an increase in the concentration of nitrogen solutions in groundwater and soils. In these farming areas, well design and controlled abstraction rates are critical in preventing penetrative depression cones, which ultimately affect water quality. To prevent any negative effects, several methods for aquifer management can be used. One common method is to set specific abstraction rules according to the hydrogeological characteristics of the aquifer, such as flow and chemical parameters, and its relationship with other water masses. These management plans are usually governed by national water agencies with support from, or in coordination with, private citizens. Transboundary or international aquifers require more complex management strategies, demanding a multidisciplinary approach, including legal, political, economic, and environmental action and, of course, a precise hydrogeological understanding of the effects of current and future usage.