Impact of Agriculture on Food Supply: A History

Chapter 3

Impact of Agriculture on Food Supply: A History

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Livia Simon Sarkadi* Department of Food Chemistry and Nutrition, Szent István University, 1118 Budapest, Somloi u. 14-16, Hungary *E-mail: [email protected].

Agriculture changed little over the past 10,000 years in terms of human employment and effort until the technological and industrial revolutions that marked the 19th and 20th centuries. Until that time, the vast majority of people were engaged in food production. In time, enough surplus food allowed for nonfood-producing activities as well. Mechanical innovations and, later, chemical creativity transformed agriculture into a multinational agribusiness supplying food for the masses, while private farming dwindled down to almost nothing. At the same time, increasing population growth, higher life expectancy, and greater affluence has ramped up the demand for food products. This chapter chronicles how the scientific community has responded to these challenges to move toward agricultural sustainability.

Importance of Agricultural Development Agriculture has undergone significant development since the earliest cultivation of plants and domestication of animals. The vast majority of the human population was engaged in both of these pursuits up until the 19th-century industrial revolution. Agricultural techniques have, so far, managed to outpace population growth, increasing life expectancy, and economic growth, but there is no telling how long the technology will be able to maintain a positive balance sheet against expanding demand for food products. Scientific advances are the mainstay of modern agriculture. Biological and chemical research are vital to keep ahead of accelerating population growth and the consequent needs to augment animal and plant productivity. Every aspect of the food production system has to be enlisted, optimized, and rendered sustainable in order to keep up with global demands, especially since our natural resources are in decline and therefore more limited than ever before. Climate change, migration, and other factors have decreased the total extent of agricultural land, making it necessary to develop methods to use previously unsuitable land for agricultural purposes. The use of fertilizers, especially the improved variety, has also been helpful in counterbalancing these losses, but every solution to a problem seems to generate more problems (1). © 2019 American Chemical Society

Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Although agricultural practices in the past have been focused on essential food production, at present, agriculture (above and beyond farming) includes forestry, dairy, fruit and mushroom cultivation, poultry production, beekeeping, and more. Today, agriculture includes not only food production but all of the ancillary means to get the food where it belongs: processing, marketing, and distribution (2). Agriculture is the undisputed backbone of our economy; without it, civilization would fall in any given social situation. Not only does agriculture provide food, it also provides employment opportunities to a very large percentage of the population.

The Greatest Breakthroughs in Agricultural History There are many excellent reviews on agricultural history with different depths of detail, but some milestones deserve greater attention. Between the 8th and 18th centuries, little advancement in agricultural technology was made. Burgeoning technology in agricultural development in the 18th century, sometimes called the agricultural revolution (1), gave rise to a significant upturn in agricultural productivity (3, 4). A brief chronology of agricultural breakthroughs is shown in Table 1.

Table 1. Chronology of Agricultural Breakthroughs (18th–21st Centuries) Date

Agricultural Breakthrough

Comment

18th Century—British Agricultural Revolution 1701

Seed drill came into use

Figure 1

1793

Cotton gin is invented

Figure 2

1798

Malthus’s book Essay on the Principle of Population is published

Ref. (6)

19th Century—Industrial Agriculture 1831

Mechanical reaper is invented

Ref. (7)

1837

John Deere introduces steel plough

Figure 3

1843

Liebig’s book Chemistry in Its Application to Agriculture and Physiology is published

Ref. (10)

1862

United States Department of Agriculture (USDA) is established

1863

Pasteurization is invented

1866

Mendel’s paper Experiments on Plant Hybrids is published

1879

First milking machine is patented

1885

Bordeaux mixture is invented

Ref. (12)

20th Century—Science-Based Agriculture 1908

Haber–Bosch process for ammonia production is invented

1918

First compressor-operated refrigerator for home use is invented

1920s

Scientific plant breeding is invented

1930s

Combine harvester is invented

1939

DDT (dichlorodiphenyltrichloroethane) is introduced as an insecticide

Figure 6

30 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Table 1. (Continued). Chronology of Agricultural Breakthroughs (18th–21st Centuries) Date

Agricultural Breakthrough

1945

Food and Agriculture Organization (FAO) is established

1960s

The green revolution occurs

1970

Environmental Protection Agency (EPA) is established

1970

Identification of the herbicidal activity of glyphosate

1973

Birth of modern genetic engineering

1980s

Integrated pest management is invented

1996

Commercial cultivation of genetically modified plants starts

Comment

Ref. (16) Ref. (16)

21st Century 2000

Golden Rice is developed to combat vitamin A deficiency

2000s

Controlled environment agriculture is invented

Ref. (17)

The 18th Century The 18th century was an important period for agriculture. Certain inventions that took place in this time period allow us to refer to it as the century of the agricultural revolution. First, simple threshing machines, horse-drawn hoes, and the seed drill came into use. A breakthrough invention was the moldboard plow whose heavy steel blade could dig up and turn over the soil in one step, enabling less suitable agricultural land to be cultivated. In 1701, the seed drill (Figure 1) was invented by Jethro Tull (1664–1741), a British agronomist, as a way to plant more efficiently. It was the first semi-automated agricultural machine with moving parts that allowed controlled distribution and planting of wheat seed.

Figure 1. Antique illustration of a seed drill. Image credit: iStock.com.

The cotton gin (Figure 2), invented in 1793 by Eli Whitney (1765–1825), was a game-changing piece of equipment that could separate cotton fiber from its stubbornly sticky green seeds 10 times faster than doing it by hand. His invention was a benchmark leap for agriculture and global economics (5). 31 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Figure 2. Eighteen-saw hand-powered cotton gin (circa late 1800s/early 1900s) for use in remote locations. Image courtesy of Lummus Corporation.

In the late 1700s, agriculture became highly organized in England. However, people on the European continent witnessed stagnant or falling yields as well as higher prices and widespread concern about food availability. Thomas Robert Malthus (1766–1834) was the first economist to propose a systematic theory of population. He correlated population growth and the resources necessary to sustain it in his famous book, Essay on the Principle of Population (1798) (6). Malthus’s central proposition stated that growth in population would always overtake growth in the food supply, creating a perpetual state of hunger, disease, and struggle. The 19th Century The 19th century was a period of profound change. The world population reached 1 billion, crop yields became sufficient to provide exports, farm equipment was largely mechanized, and farm size expanded, leading invevitably to the decline in the number of farms. Between 1850 and 1900, the population of industrialized nations grew from 500 to 800 million while at the same time diet changed: per capita calorie consumption increased, consumption of animal protein increased, and cereal consumption decreased. Agricultural science increased in prominence and efficiency so that at last there was enough food to feed the world. New inventions, developments in the chemical sciences, and new techniques based on sound scientific ideas all contributed to this achievement. One major example is the steel plow, introduced by John Deere (1804–1886), an American blacksmith and manufacturer, in 1837. The company he founded, Deere and Company (1876), eventually became one of the largest and most prominent agricultural and construction equipment manufacturers in the world. The genius of Deere’s innovation was to discard the cast-iron moldboard from the traditional plow made for rocky farm fields and replace it with a dynamically curved moldboard of wrought iron or steel. Steel became the mainstay material of farm machinery from then on, as illustrated by the modern seed drill in Figure 3. Cyrus Hall McCormick (1809–1884) (Figure 4) was a Chicago industrialist who invented the first commercially successful mechanical reaper (1831), a horse-drawn machine to harvest wheat (7). The invention, one of the most important in the history of farm innovation, caused him to assume the appellation of “father of modern agriculture.” 32 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Figure 3. Great plains seed drill. This machine illustrates the evolution of farming from the simple seed drill of Figure 1 to the massive farming technology of the 20th century. Photo courtesy of Mary Virginia Orna.

Figure 4. Cyrus Hall McCormick (1809–1884). Image credit: iStock.com.

Perhaps the most well-known scientist of this period was Justus von Liebig (1803–1873) (Figure 5), professor of chemistry at the University of Giessen in Germany. He was among the first to recognize the importance of analyzing organic compounds, and early on he published works on the use of inorganic fertilizers (8). He is often regarded as a founding father of agricultural chemistry. He found by experiment that nitrogen was an essential nutrient for plants and applied chemistry’s “limiting reagent” concept to plant growth to explain why the scarcest nutrient always controlled the results (9). His book, Chemistry in Its Application to Agriculture and Physiology, published in 1843 (10), launched the systematic development of the agricultural sciences.


Figure 5. Justus von Liebig (1803–1873). Image credit: Illustrated London News 1873, 62, 418 1873/ Mary Evans Picture Library. Little did Louis Pasteur (1822–1895) realize, as he struggled in his laboratory, that his would become the most famous scientific name in history, printed on every milk container produced, at least in the U.S. In 1863, Pasteur, a French chemist and biochemist, developed the method that came to bear his name, pasteurization. Between the years 1860 and 1864, Pasteur gradually came to the conclusion that contagious diseases could be attributed to the existence of pathological microorganisms, and this insight led him to invent a process that would destroy them in food and beverage products. Pasteur was an eclectic scientist who dabbled in many things. Could it be that his research on the mechanism of contagion led to the synergistic relationship between the practice of pasteurization and the theory of germs? His legacy is concretized in the Pasteur Institute, a recognized pioneer in the field of global public health since Pasteur founded it in 1887. Two decades later, in 1885, the French botanist Pierre M. A. Millardet (1838–1902), a professor at the University of Bordeaux, made a great advance in mildew control. Mildew, a fungus that thrives in humid environments, was attacking grape vines in southern France, causing economic panic in the industry. Millardet serendipitously concocted an aqueous mix of copper(II) sulfate (CuSO4) and slaked lime (Ca(OH)2) that, when sprayed on fruit and leaves, was effective in controlling the fungus if it had not progressed beyond the spore stage. Later research attributed the mode of action to the presence of copper, which interfered with the fungal spores’ enzymes, preventing them from germinating. The lime was necessary to precipitate, and thus stabilize, the copper. The use of this socalled Bordeaux mixture was so successful that it became the first fungicide to be used on a large scale. One might call it the “granddaddy” of crop protection agents: it is still in use over a hundred years later. The 20th Century By 1930, the world population had reached 2 billion and the land available for crops inevitably became a limiting factor. Increased crop yields became a priority. Of all the essential nutrients, nitrogen is required by plants in large amounts and, because of the dearth of fixed nitrogen in nature, can be the scarcest of the major essential plant nutrients. Thus, creating synthetic N-fertilizer with the Haber–Bosch process became the most important development of the 20th century.


In 1909, Fritz Haber, a professor of physical chemistry at the University of Karlsruhe in Germany, began to “tinker” with the nitrogen–nitrogen triple bond in elemental nitrogen. His previous research experience with bond strengths and thermodynamics of other molecular types in the gaseous state led him to speculate on the possibility of achieving a decent yield of ammonia by combining elemental hydrogen and elemental nitrogen. Atmospheric nitrogen was in plentiful supply; Haber had to “borrow” the hydrogen from natural gas, methane (CH4). Eventually he succeeded in producing a few milliliters per hour of ammonia solution when he reacted the N2 and H2 at high temperatures and pressures in the presence of an iron catalyst. It took the engineering skill of Carl Bosch (1874–1940), an industrial chemist at BASF, to scale up the process and render it commercially viable. It would be a gross understatement to call this development revolutionary; even the most exaggerated superlative would only weakly convey the impact that this achievement had on the world’s food supply. Haber’s work was recognized by the conferral of a Nobel Prize in 1918; Bosch’s Nobel had to wait until 1931. As with many boons in life, the Haber–Bosch process had its dark side. It is a fact of history that it was responsible for the prolongation of World War I by at least a year, and that it enabled Germany to engage in yet another war not long afterward. In both cases, it empowered Germany to manufacture the nitrates necessary for producing high explosives by putting fixed nitrogen, in the form of ammonia, into its war chest. Furthermore, many question whether or not the population boom we are now engulfed in could have taken place without a virtually unlimited supply of a plant’s most essential nutrient. Other Developments The compressor-operated refrigerator (1918): At the beginning of the 20th century, a new technology for food preservation became available for household use. The compressor-operated refrigerator was introduced by the firm Kelvinator in 1918. Refrigerators quickly spread in restaurants and grocery stores because cold storage provided the ability to store fresh foods safely as well as reduce food losses and wastes (11). Today, cold storage is an essential part of food industry and food transportation. There are many types of cold stores available, such as refrigerated buildings, warehouses, and refrigerated trucks. Scientific plant breeding (1920s): Gregor Mendel (1822–1884) discredited the blending theory of inheritance and instead proposed laws for inheritance patterns as described in his 1866 paper, Versuche über Pflanzen-Hybriden (Experiments on Plant Hybrids) (12). Mendel’s paper was the basis for discoveries in the early 20th century that shed light on the vital mechanisms of plant breeding. Consequently, he is known as the father of modern genetics. The combined harvester (1930s): The combined harvester (Figure 6) could efficiently harvest a variety of grain crops in a single, combined process of reaping, threshing, and winnowing. This type of mechanization brought profound changes to global food production. DDT (1939): With control of insect pests as his goal, Paul Hermann Müller (1899–1965), a Swiss chemist, rediscovered DDT (dichlorodiphenyltrichloro-ethane), a relatively inexpensive organochlorine compound that had been synthesized more than a half-century earlier and was thought to have insecticidal properties. Müller experimentally confirmed these previous insights; its subsequent widespread use led to the virtual elimination of malaria and effective control of insect parasites on trees and crops. DDT was actually first synthesized in 1873 by Austrian chemist Othmar Zeidler (1850–1911), but it was Müller who discovered its efficacy as an insecticide and for this reason was awarded the Nobel Prize in Physiology or Medicine in 1948. For over 20 years thereafter, 35 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

DDT and similar pesticides were employed to manage crop pests and insect-borne diseases. But in the 1960s, many public health–related concerns regarding DDT’s accumulation in the human body, along with questions about its decreasing effectiveness and environmental impact, led to its decline and eventual discontinuance. Ongoing research in sustainable agriculture has led to a new generation of pesticides that are safer and more environmentally friendly.

Figure 6. Combined harvester and thresher. Photo courtesy of Kansas Historical Society. The green revolution (mid-20th century): The green revolution is defined as an intensive plan initiated in the 1960s to introduce more sustainable agricultural techniques with the goal of producing more food in developing countries. Two key means of attaining this objective were the introduction of “friendlier” fertilizers and plant strains shown to be higher-yielding. Norman Ernest Borlaug (1914–2009), an American plant pathologist and geneticist, played a central role in promoting the green revolution, not only for his scientific know-how in wheat breeding, but also for his humanitarian efforts to increase food production worldwide. For these reasons, he was awarded the Nobel Peace Prize in 1970. There are several pros and cons of the green revolution. Food production increased more than 1000% in some places, but also resulted in biodiversity loss and other detrimental effects on the environment. With the consequent population explosion in the target areas, the green revolution helped keep hunger at bay but did not eliminate famine. On the contrary, it led to increased costs of production and negative environmental impacts. In addition to crops, livestock production and dairy farming have undergone remarkable development during the past centuries. Farm mechanization dramatically increased farm efficiency and productivity (11). The first successful milking machine that replaced hand milking was patented by Anna Baldwin in 1879. Many milking machines in the 19th century were designed either to imitate hand milking by using mechanical pressure or the sucking calf by using a vacuum. One of the main disadvantages of the early vacuum milkers was that they often injured the cow’s udder. Over subsequent decades, many new technologies (e.g., pulsator, surge milker) were invented to improve the way milk was collected. Modern milking machines are completely closed pipelines. Today, the computerization of dairy farming is increasingly common. Between 1768 and 1786, a drastic decrease in cattle husbandry occurred due to the infectious viral cattle plague epizootic (rinderpest). The radical measure of killing sick and suspected animals 36 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

stopped the disease and the infectious agent died out in Europe for a long period of time. By the time that cattle husbandry was ready to make a comeback in the 19th century to supply farmers with manure, it turned out to be a near obsolete enterprise because of the ready availability of fertilizer from other sources (11). Although rinderpest reared its head again in the 20th century, scientific research yielded an effective vaccine that has virtually stamped out this disease worldwide (13, 14). In the 21st century, livestock production is characterized by two typical methods: intensification (indoor animal housing all year round) and specialization (one animal species is produced) Currently, applied breeding techniques and modern genetics are the main factors influencing increase in livestock production. In developed countries, the major causes driving the accelerating demand for products from domestic animals are greater affluence, urban expansion, and, as always, population growth. In the future, availability and quality of these products will possibly be influenced by environmental concerns and animal welfare legislation (15). In the 1970s, a new technology, genetic engineering, began to be viewed as a godsend for achieving the seemingly unattainable goals required for ramping up sustainable agriculture. Many scientists believe that genetically modified organisms (GMOs), specifically plants, represent one of the breakthroughs in the modern history of agriculture. The main goal of GMOs is to cultivate new plant strains that can resist detrimental environments like petrochemical seepage, arid conditions, or rapid climate change and still remain high-yielding. The birth of modern genetic modification dates back to 1973, when a GMO was successfully produced for the first time (16). A similar procedure was utilized in animals (17). Further milestones in genetic engineering include the following (18): Humulin, the first FDAapproved genetically engineered (GE) pharmaceutical (1982); Flavr Savr tomatoes became the first GE food (1992); Bt (Bacillus thuringiensis) potato, a crop that produces its own insecticide, was EPA-approved (1995); an herbicide-resistant crop was first introduced (1996); and Golden Rice, GE to biosynthesize the vitamin A precursor ß-carotene (2000). However, there are many fears concerning the possible unknown consequences of genetically modified crops on human health, including scientific, economic, political, and ethical issues (11). Some countries, including Hungary, have regulations to keep the GMO-free status of their agriculture a strategic priority issue. Industrial Agriculture Science-based agriculture is a 20th-century phenomenon. Industrial agriculture is its offshoot: a practice that depends on the products generated by modern science for its growth and survival. It is an entire structure that cannot function without all of these requisites in place: pesticides and synthetic fertilizers to enhance crop yield, reliable and massive irrigation systems, a worldwide transportation network, and suitable machine technology. None of the parts of the structure came about all at once, but it gradually enveloped the entire world as its benefits became obvious to industry and to government. This new type of agriculture clearly has many benefits: greater crop yields, produced much more efficiently, less expensive food, big business profitability, and broader export horizons. In developed countries, there is an increasing interest in agriculture driven by consumer demand to produce fresh, healthy, and safe foods year-round. One methodology that has drawn a lot of attention is controlled environment agriculture, which seeks to utilize the lessons learned from hydroponics and aquaculture to provide crop-growing solutions in environments and regions where there is little or no arable land such as desert and urban areas. This technology is likely to become more widespread in appropriate locations in response to factors that threaten food security (19). 37 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

The downside of industrial agriculture includes its negative environmental impact. Massive and unsustainable consumption of water, soil and air pollution by synthetic pesticides and fertilizer runoff, unrecoverable soil through erosion, biodiversity of both plants and animals jeopardized by monocultures, degradation of aquatic life by the overconcentration of vital nutrients—these are only some of the consequences, and hence challenges, that face us as we proceed into the 21st century. The 21st Century Trends and Challenges As we ponder the future of agriculture, we realize that we face many challenges mostly inherited from 20th-century practices and two seemingly uncontrollable factors: a growing world population and climate change. Linked to the pollution, degradation, depletion, and even exhaustion of worldwide land and water resources are even more undesirable issues: increasing production costs, massive migration of peoples, rising poverty, unsustainable urbanization, loss of farms to agribusinesses, and a vanishing rural population. The Food and Agriculture Organization of the United Nations (FAO) Strategic Framework has identified 15 trends and 10 challenges that will shape future agricultural practice (20). The main trends include: • Urbanization, aging, and accelerating world population increase. Providing enough food for an expected world population of 9 billion by 2050, almost 10% of whom will reside largely in Africa and South Asia, is our greatest challenge. With little opportunity for employment, this population trend is presently spurring faster rates of emigration, to say nothing of rampant violence and war. Since urban dwellers depend on the market for 90% of their food (as opposed to only 40% for rural dwellers), rapid urbanization is cause for concern: each urban dweller consumes almost twice as much of the food supply than a person in a rural setting. • Climate change. Predicated on meteorological trends of the past several decades, changes in the climate are expected to increase the median temperature by as much as 5°C and median precipitation by as much as 20% by the end of this century, thereby threatening worldwide nutritional needs. We have already witnessed more frequent and debilitating droughts as well as remarkable flooding in many areas. Their continuance will assuredly reduce crop yields in general (21). • Agricultural productivity and innovation. The world’s agricultural area is actually shrinking due to increasing urbanization, soil erosion, and nutrient exhaustion, and an alarming number of regions are now affected by water scarcity. The agricultural system will have to produce as much as 50% more food resources by 2050 than it has recently in order to make up for these changes. • Dietary transitions affecting nutrition and health. Average per capita food consumption is expected to grow across the board to about 3,000 calories per day. Not all of these calories will supply the necessary micronutrients that must be present in any diet, but they will unnecessarily enrich the diet with lipids and carbohydrates, thus leading to serious undernutrition in the wake of overconsumption. Even presently, almost 30% of the world’s adults suffer from micronutrient malnutrition and 40% of them are overweight or obese. Of the 129 countries with statistical data in this area, over 44% of them report critical degrees of adult overweight and undernutrition. 38 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

• Changing food systems. Increased population growth demands increased efficiency in food processing, transportation, distribution, and storage, giving rise to large-scale automated systems to accomplish these needs. The negative impact on the livelihoods of small farmers is incalculable (22). • Food loss and waste. Although most of the world’s attention has been focused on supplying enough food for a growing population, little attention has been paid to the enormous losses and waste of food, as much as one third, all along the production chain. (23). While a fair amount of this loss is unavoidable due to such factors as spoilage during transfer, there has been a growing emphasis on moving away from site-specific producer-level losses to an examination and restructuring of the entire food supply chain (24). Additional trends identified by the FAO strategic framework (20) are: • Various trends in agricultural speculation, family livelihoods, financial disparity, and economic growth; • Expanded rivalry for natural resources; • Unregulated spread of plant pests and diseases; • Growing international conflicts, unprecedented natural disasters, and other types of destabilizing crises; • Unrelenting food insecurity driven by poverty and inequality; • Organizational ups and downs in economic systems and their implications for employment; • Changed international response systems regarding food and nutrition security issues; • Alterations in international financing structures for development. The 10 challenges (20) revolve around addressing many of the issues already mentioned: (1) improving agricultural productivity, the natural resource base, efficiency and resiliency of food systems, and earning opportunities in rural areas; (2) dealing with poverty, inequality, hunger, malnutrition, migration, climate change, and food system threats from pests and disease; and (3) building flexibility toward ongoing conflicts, disasters, and crises as well as structures for coherent and effective international cooperation.

Sustainable Agriculture Among these challenges, perhaps the most important one is sustainable agricultural development, which may offer solutions to the challenges enumerated previously. To speak of the issue of sustainable agricultural development, we must first define “sustainable agriculture” itself, which was addressed by Congress in the 1990 Farm Bill (25): “The term sustainable agriculture means an integrated system of plant and animal production practices having a site-specific application that will, over the long term: satisfy human food and fiber needs; enhance environmental quality and the natural resource base upon which the agricultural economy depends; make the most efficient use of nonrenewable resources and onfarm resources and integrate, where appropriate, natural biological cycles and controls; sustain the economic viability of farm operations; and enhance the quality of life for farmers and society as a whole.”


By moving this “integrated system” to the development stage, we must broaden our idea of a “system” to a “process,” and one that contributes: “to improving resource efficiency, strengthening resilience, and securing social equity/responsibility of agriculture and food systems in order to ensure food security and nutrition for all—now and in the future” (26). Among the more specific aims of sustainable agriculture are the following: • • • • • • • • • •

Food safety and quality; Conservation in all its forms with future generations in mind; Judicious management of chemical inputs; Adaptation and, if possible, mitigation of climate change; Economic viability; Sustainable farming; Attention to the needs and challenges of the ecosystem; Biodiversity protection; Farm worker welfare and quality of life; Animal welfare.

Developments in Science and Technology Developments in science and technology have contributed to the formation of an agricultural structure in which the multivariate processes that used to be called “farming”—sowing, reaping, warehousing, and shipping agricultural products—has become agribusiness with a global reach. Specific specialty systems within this structure include organic agriculture and integrated pest management that have been developed to reduce environmental damage and increase the quality of food (1). Organic Agriculture When, in October 2002, the USDA promulgated its National Organic Program (27) for agricultural products, it set up a system for certification and labeling that guaranteed consistency. Consequently, any label placed on an agricultural product that says “USDA Organic” informs and assures the consumer that said product is free from interventions that have become commonplace in modern food production: pesticides, synthetic fertilizers, fertilizer sludge, genetic engineering, ionizing radiation, antibiotics, and growth hormones. Although these products are treated to minimize the effects of air, soil, and water pollution, there is no guarantee that they are totally free of residual processing materials. Furthermore, raw, fresh, and processed foods containing organic ingredients also come under the aegis of USDA labeling rules. The markets for organic food have been growing continuously since these products became available. Organic farming has major advantages with regard to several main environmental impacts, like eschewing pesticides, but on the other hand, it requires higher land use compared to conventional farming. There is growing literature on how organic agriculture contributes to sustainable development. One such paper (28) shows how to combine organic farming with various strategies, including decreasing utilization of animal products, avoiding concentrated fodder for domestic animals, and cutting down on food waste, to maintain sustainability. The study revealed 40 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

that even if only 60% of agricultural activity were converted to organic farming and concentrated fodder and food waste were each reduced by 50%, considerably reduced environmental impacts would result. Pest Management For pest management to be considered “integrated,” all appropriate tools to deal with pests must act in concert with one another. Physical approaches such as trap use and hand weeding should go hand in hand with chemical (pesticides), biological (biocontrol agents), and sustainable agronomic practices so as to lessen environmental and health risks. Pesticides Pesticides, a major tool in pest management and crop protection, are chemical agents that have been synthesized with the purpose of controlling agricultural and other pests. They are categorized as herbicides, insecticides, fungicides, and fumigants. Their use is widespread, with both positive and negative consequences. Important benefits encompass control of insects, pathological organisms, and undesirable plant species. The downside is inadvertent farm worker poisoning, mass extermination of beneficial and economically important organisms, unintended environmental damage including pesticide residue dispersion, and contamination of the food supply (29). Pesticide residues are thoroughly monitored and tolerances are enforced by the appropriate governmental agencies in both the European Union (EU) and in North America. Recent analytical data indicate a general compliance with acceptable levels; for example, a 2014 study from 28 member states of the EU showed that 97% of more than 83,000 food samples were within legal parameters (30). Herbicides Herbicides are substances, usually chemical, that are toxic to plants. Today, there are eight different types of herbicides that can be selected, depending on their properties, for effective weed control. However, this availability is relatively recent, being the result of chemical research largely during the 20th century. Before that time, little attention was paid to the existence of weeds among the wheat, even though some writers declared that weed growth diminished the productivity of the land as early as late Roman times. Weeds were considered an inevitable agricultural inconvenience; the price of removing them by hand, which usually entailed a large degree of manual labor, was considered too high to pay by most farmers. However, over the course of about 50 years, from 1875 to 1925, great progress was made in developing mechanical cultivators that were very effective in eliminating weeds. Chemical substances were not neglected in ancient and medieval times, but their use was largely confined to dealing with diseases and with insect control. Only much later, in the mid-19th century, were substances like salt and lime mentioned as suitable as weed-killers. In 1855, Gustav Kirchhoff (1824–1887), the German physicist famous for his collaborative work with Robert Bunsen (1811–1899) in discovering several new chemical elements, recommended sulfuric acid and iron sulfate for controlling weeds. Subsequently, other chemical substances such as copper sulfate, various arsenic compounds, carbon disulfide, ammonium sulfamate, and boron compounds were found to be phytotoxic as well. The true watershed moment occurred in 1941 when the art of organic chemical synthesis gave rise to (2,4- dichlorophenoxy)acetic acid (2,4-D) and (2,4,5-trichlorophenoxy)acetic acid (2,4,541 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

T) as part of a joint effort between the United States and the United Kingdom during World War II to develop chemical warfare agents. Things took off rapidly from there: between the years 1950 and 1970, more than 75 new synthetic herbicides were introduced for public use. These chemicals are the survivors of rigorous testing that thousands more compounds were put through before being judged acceptable or not. As one might expect, legislative and regulatory developments kept pace with the new discoveries (31). In 1970, a discovery at Monsanto by chemist John Franz (b. 1929), glyphosate (also known as Roundup), became the herbicide gold standard because of its many favorable properties. It is an extremely effective enzyme inhibitor that has a high affinity for soil, and consequently there is little runoff into the environment. Furthermore, it is plant-specific: it has no effect on other living creatures. At present, glyphosate is the most frequently and widely used herbicide in the world. However, it is a known carcinogen whose long-term effects on the environment have yet to be fully studied (32, 33). Figure 7 shows the structural formulas for two key herbicides. The jury is still out on whether glyphosate should be removed from the market; its usefulness is undeniable, but many question if the same can be said about its safe use.

Figure 7. Left: One of the first chemically synthesized herbicides, 2,4-dichlorophenoxy)acetic acid (2,4-D); Right: The most widely used herbicide in the world, N-(phosphonomethyl)glycine (glyphosate). Insecticides Insecticides are designed to kill insects and arachnids (e.g., spiders, ticks, and mites). Insects that feed on plants are of particular interest to agriculture because many species attack various parts of crop plants, such as roots, stems, tree trunks, and leaves. Studies have shown that even if these insect herbivores do not manage to kill a plant, they certainly can reduce plant size and seed production (34). Many insect pests that impact plant life have benefited from climate change over the past decade or two, thus upsetting an ecological balance that maintained control of their influence and spread. For example, the pine bark beetle infestation in the Rocky Mountains is greater than it has ever been, and much of the damage has been attributed to the warmer winters in the region, leading to survival of insect eggs that would normally die during colder winters (35). Several studies indicate that this trend may be one of the more unpleasant surprises related to climate change (36). Chemically derived insecticides have often been viewed as the panacea for insect herbivore control. One example is stemofoline, an insecticidal alkaloid produced in the plant Stemona japonica. It works, as do many insecticides, by interfering with the insect’s nervous system. It has a good spectrum of activity with rapid action and is a potent agonist of the nicotinic acetylcholine receptor in insects. The downside is its highly complex polycyclic structure, which poses a challenge for the synthetic chemist. A breakthrough came with the recognition of a tropane substructure embedded within the molecular framework of stemofoline. During the exploration of various tropanes, a series of highly active cyanotropanes were discovered with high potency against aphids and whitefly and rapid action both by contact and stomach routes (1). However, recent data suggest that since a large proportion of insect pests, specifically 55% of insect herbivores tested, have developed resistance to 42 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

at least one or more pesticides (37), our future efforts should be directed to research and exploitation of plants’ built-in natural defense systems—a better option for the plants, the environment, and all of humanity. Fungicides and Fumigants Fungicides are designed to control molds, mildews, and other fungal pathogens by either killing them or preventing spore growth. They do this usually by disrupting the chemical pathways within fungal cells or by damaging the cell membrane itself. Proper diagnosis of the pest problem is vital before deciding on a fungicidal agent since some unintended consequences like killing beneficial organisms in the wake of fungus extermination is common. Users must also be clear about fungicides’ limitations: they cannot increase crop yield; they can only protect crop potential yield (38). The first fungicide to be introduced through creative chemistry was dithiocarbamate in 1934; the strobilurin fungicides followed in 1996. The leading fungicide today is one of the latter, azoxystrobin (1). Fumigants are toxic volatile substances designed to kill pests by completely enveloping a space to poison any pest within. Choice of a fumigant depends upon the type of pest to be eliminated and the circumstances of infestation. There are not many compounds suitable for fumigation because of toxicity, corrosive properties, or other undesirable features that proscribe usage in a closed space. Furthermore, as more information is gathered on the deleterious effects of fumigants on nontargeted organisms, the choice is becoming even narrower. Compounds that are gaseous at normal temperatures and pressures are not used because of difficulty of control and possibility of escape. Several sulfur compounds and halogenated hydrocarbons are the main chemical categories for commercial fumigants commonly in use (39). Industrial Chemicals The pesticides described in this section all fall within the category of industrial chemicals, chemical substances manufactured on a large scale and deployed throughout the world by for-profit entities. It goes without saying that regulation of these substances, many of which are highly toxic and may have long-term deleterious effects on the environment, is a necessary step. This was the intent when, in 2007, the EU instituted a new policy called REACH (Registration, Evaluation, and Assessment of Chemicals), charged with creating a centralized database to make available the information on risks and substance evaluations forwarded to it by industry. Looking forward to 2020, the EU plans on taking further action to carry out REACH’s goals, to improve the quality of life of its residents, and to more responsibly manage the environment, especially as it regards the use of chemical substances (40).

Conclusion When it comes to agriculture, the term “global village” is not a euphemism. We have seen by reviewing its history that the stakes are very high for sustained food production given the exploding demands, environmental degradation, unprecedented natural disasters, and population growth that both challenge and burden the enterprise. We have seen that chemical research, in identifying the fundamental reactions that sustain and grow living things, enabled extraordinary advances in such areas as increasing food abundance, quality, and variety. Chemistry also created ways and means of protecting the food supply using synthetic chemical substances. By doing so, it created its own problems of environmental pollution, food contamination, and threats to public health that must be 43 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

addressed. While it is widely recognized that integrated management of all of these issues demands that nations commit to working together and devising transnational agreed-upon and enforceable policies, the current wave of extreme rightist politics is changing these priorities. What the future holds is possibly a set of unanticipated surprises and unintended consequences.

Biographical Information Livia Simon Sarkadi is full professor and head of the Department of Food Chemistry and Nutrition at the Szent István University, Budapest, Hungary. She started her carrier at the Technical University of Budapest (BUTE). She received a PhD degree in Biochemistry from the BUTE in 1986 and a Candidate of Sciences degree in Food Chemistry from the Hungarian Academy of Sciences (HAS) in 1991. She was awarded a Dr. habil. from BUTE (1999) and a DSc degree in Chemical Science from HAS (2010). Her research centers on aspects of food quality and food safety, with a particular emphasis on amino acids and biogenic amines and on biochemical aspects of abiotic plant stress. She is an author/coauthor of over 100 scientific papers in these areas. She has served as chair of the Food Protein Working Group of HAS since 1996 and as president of the Hungarian Chemical Society since 2011. She was chair of the Food Chemistry Division of the European Association for Chemical and Molecular Sciences from 2009 to 2014 and is currently an elected member of the executive board. She is very active in organizing scientific conferences and a member of the editorial boards of three international journals.

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Impact of Agriculture on Food Supply: A History

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