James M. MacDonald
Industrialized livestock production can be characterized by five key attributes: confinement feeding of animals, separation of feed and livestock production, specialization, large size, and close vertical linkages with buyers. Industrialized livestock operations—popularly known as CAFOs, for Concentrated Animal Feeding Operations—have spread rapidly in developed and developing countries; by the early 21st century, they accounted for three quarters of poultry production and over half of global pork production, and held a growing foothold in dairy production.
Industrialized systems have created significant improvements in agricultural productivity, leading to greater output of meat and dairy products for given commitments of land, feed, labor, housing, and equipment. They have also been effective at developing, applying, and disseminating research leading to persistent improvements in animal genetics, breeding, feed formulations, and biosecurity. The reduced prices associated with productivity improvements support increased meat and dairy product consumption in low and middle income countries, while reducing the resources used for such consumption in higher income countries.
The high-stocking densities associated with confined feeding also exacerbate several social costs associated with livestock production. Animals in high-density environments may be exposed to diseases, subject to attacks from other animals, and unable to engage in natural behaviors, raising concerns about higher levels of fear, pain, stress, and boredom. Such animal welfare concerns have realized greater salience in recent years.
By consolidating large numbers of animals in a location, industrial systems also concentrate animal wastes, often in levels that exceed the capacity of local cropland to absorb the nutrients in manure. While the productivity improvements associated with industrial systems reduce the resource demands of agriculture, excessive localized concentrations of manure can lean to environmental damage through contamination of ground and surface water and through volatilization of nitrogen nutrients into airborne pollutants.
Finally, animals in industrialized systems are often provided with antibiotics in their feed or water, in order to treat and prevent disease, but also to realize improved feed absorption (“a production purpose”). Bacteria are developing resistance to many important antibiotic drugs; the extensive use of such drugs in human and animal medicine has contributed to the spread of antibiotic resistance, with consequent health risks to humans.
The social costs associated with industrialized production have led to a range of regulatory interventions, primarily in North America and Europe, as well as private sector attempts to alter the incentives that producers face through the development of labels and through associated adjustments within supply chains.
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.
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
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.
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.
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.
Rene Van Acker, Motior Rahman, and S. Zahra H. Cici
The global area sown to genetically modified (GM) varieties of leading commercial crops (soybean, maize, canola, and cotton) has expanded over 100-fold over two decades. Thirty countries are producing GM crops and just five countries (United States, Brazil, Argentina, Canada, and India) account for almost 90% of the GM production. Only four crops account for 99% of worldwide GM crop area. Almost 100% of GM crops on the market are genetically engineered with herbicide tolerance (HT), and insect resistance (IR) traits. Approximately 70% of cultivated GM crops are HT, and GM HT crops have been credited with facilitating no-tillage and conservation tillage practices that conserve soil moisture and control soil erosion, and that also support carbon sequestration and reduced greenhouse gas emissions. Crop production and productivity increased significantly during the era of the adoption of GM crops; some of this increase can be attributed to GM technology and the yield protection traits that it has made possible even if the GM traits implemented to-date are not yield traits per se. GM crops have also been credited with helping to improve farm incomes and reduce pesticide use. Practical concerns around GM crops include the rise of insect pests and weeds that are resistant to pesticides. Other concerns around GM crops include broad seed variety access for farmers and rising seed costs as well as increased dependency on multinational seed companies. Citizens in many countries and especially in European countries are opposed to GM crops and have voiced concerns about possible impacts on human and environmental health. Nonetheless, proponents of GM crops argue that they are needed to enhance worldwide food production. The novelty of the technology and its potential to bring almost any trait into crops mean that there needs to remain dedicated diligence on the part of regulators to ensure that no GM crops are deregulated that may in fact pose risks to human health or the environment. The same will be true for the next wave of new breeding technologies, which include gene editing technologies.
Coffee is an extremely important agricultural commodity, produced in about 80 tropical countries, with an estimated 125 million people depending on it for their livelihoods in Latin America, Africa, and Asia, with an annual production of about nine million tons of green beans. Consisting of at least 125 species, the genus Coffea L. (Rubiaceae, Ixoroideae, Coffeeae) is distributed in Africa, Madagascar, the Comoros Islands, the Mascarene Islands (La Réunion and Mauritius), tropical Asia, and Australia. Two species are economically important for the production of the beverage coffee, C. arabica L. (Arabica coffee) and C. canephora A. Froehner (robusta coffee). Higher beverage quality is associated with C. arabica. Coffea arabica is a self-fertile tetraploid, which has resulted in very low genetic diversity of this significant crop. Coffee genetic resources are being lost at a rapid pace due to varied threats, such as human population pressures, leading to conversion of land to agriculture, deforestation, and land degradation; low coffee prices, leading to abandoning of coffee trees in forests and gardens and shifting of cultivation to other more remunerative crops; and climate change, leading to increased incidence of pests and diseases, higher incidence of drought, and unpredictable rainfall patterns. All these factors threaten livelihoods in many coffee-growing countries.
The economics of coffee production has changed in recent years, with prices on the international market declining and the cost of inputs increasing. At the same time, the demand for specialty coffee is at an all-time high. In order to make coffee production sustainable, attention should be paid to improving the quality of coffee by engaging in sustainable, environmentally friendly cultivation practices, which ultimately can claim higher net returns.