SAS
Topic 1 - Agriculture's Evolution and Revolution - Part 1
Key concepts include:
Agriculture is environmentally the most invasive of industries. However, agricultural expansion and intensification has provided a crucial service to humanity. There is a trade-off between food production and environmental deterioration.
Reasons for California's preeminence in U.S. and world agriculture
Benefits and negatives associated with the rise of agriculture-based communities in human history
Nitrogen from air feeds the world
The Haber-Bosch process
Topic 1 - Agriculure's Evolution and Revolution - Part 2
Key concepts include:
Corn production in the U.S.
delta 13C and why we are "corn"
Boosting output with kilowatts of inputs through mechanization
Boosting output and quality through chemistry
DDT: the good and the bad
Rachel Carson and Silent Spring
Consumer exposure to pesticides in foods: what the data show
Topic 2 - Population and Food
Key concepts include:
Projections for world population peak around 9.5-10 billion, occurring during the 21st century.
Fertility rates are higher in developing countries; most growth will occur in sub-Saharan Africa.
The ideas of Thomas Malthus regarding the relationship between population and food supplies.
Modern humans have invented ourselves out of cycles of growth and decline that typically occur among other animal populations.
Humans have a huge impact on the planet’s resources. The trajectory of current consumption is not sustainable.
The U.S. has one of the highest relative poverty rates among industrialized countries.
Most American households are food secure. About 13% of households are food insecure (~42 million people).
Obesity can co-exist with food insecurity.
Food insecurity and participation in food assistance programs tracks the number of people in poverty.
Know the meanings of hunger, under-nourishment, malnutrition, and wasting.
Topic 3 - Feeding the World Today
Key concepts include:
World average consumption ~2,800 Cal/day/person.
Relationship between dietary energy supply and a country’s wealth as measured in GDP per person is not a straight line.
Wheat, maize and rice: the big three staple crops worldwide.
Diets vary in different regions of the world but cereal grains dominate source of Calories.
Meat production requires a lot of fossil fuel: 2-3 Calories of fossil fuel to produce 1 Calorie of protein from soybeans, corn, or wheat. For beef it takes as much as 35 Calories of fuel to produce 1 Calorie of protein (you will see different estimates in the literature).
Almost HALF of the world’s harvest is fed to animals. Globally, about 40% of cereals and 90% of the ever-increasing soybean harvest goes for animal feed.
Worldwide meat production increased nearly 5 times in the second half of the 20th century, and the amount eaten per person doubled. With current projections, meat consumption in the near future will put enormous pressure on crop and water resources.
Topic 4 - Farming Systems and Sustainability
Key concepts include:
Agriculture typically replaces natural landscapes and ecosystems with fields of alien plants and animals.
The number of farms, farmers, and farm workers in the U.S. has steadily decreased since the 1930s, with about 2.1 million farms currently in the U.S. and the majority small retirement farms. However, most of our food is produced on large family-owned or corporate farms.
Modern farming relies on machines that require fossil fuel energy to generate a lot of horsepower.
Conventional (industrial) farms utilize synthetic chemical fertilizers, pesticides, herbicides, and other inputs, hybrid and transgenic crops. Many rely on irrigation and vary in tillage practices.
Organic agriculture in the U.S. operates under regulations set forth by the USDA. The use of synthetic fertilizers, pesticides, and growth regulators as well as transgenic crops is prohibited.
Sustainable agriculture is economically viable, environmentally sustainable, and socially responsible.
Sustainable agriculture practices are incorporated into both conventional and organic agriculture.
Most organic food derives from products of industrial-scale farms that use organic practices.
There are many different cultivation systems. Some are very energy intensive, others futuristic, and some incorporate principles of sustainability.
There are challenges in fertilizer availability and demand that we face now and in the future.
The supply of animal manures is insufficient to meet nitrogen demands of the crops we rely on to feed the world. Mineralization of nitrogen from green manures takes time and is dependent on many soil factors.
Topic 5 - Farm Energy Balance
Key concepts include:
Oil consumption in the U.S. is about 7 billion barrels per year. World consumption is about 94 million barrels per day (i.e., 34 billion barrels per year).
Oil, as a fossil fuel, is a finite resource. There is uncertainty in peak oil estimates and when we will run out, but most models predict that we have less than 100 years left, and possibly less.
Oil, natural gas, and coal are the big three sources of the world’s energy.
Most of our oil reserves are unconventional oil and therefore difficult to access.
38% of world grain production goes to feed livestock.
Beef from cattle as produced in the U.S. is an inefficient source of food relative to other protein sources, with a large footprint on the environment.
Milk from dairy cows is very efficient.
Crops vary in the amount of water they require. In California, alfalfa production uses as much as 15% of total irrigation water in the state.
Different practices lead to different outcomes in terms of the kcal (Cal) that we can derive from a food vs. the kcal (Cal) of input to produce that food.
Most of the energy required to make a can of corn is in the processing and packaging.
For our typical 3,600 Cal diet, fossil fuel energy input for a “meat-sweet” non-vegetarian diet far exceeds that for vegetarian diets.
Burning plant biomass (cogeneration), methane digesters, biodiesel, and bioethanol are examples of biofuel processes.
In the U.S., the amount of corn used for bioethanol is similar to the amount used for livestock feed, and in some recent years surpassed the amount used to feed livestock.
Cellulosic ethanol as a source of fuel has both pros and cons.
Topic 6 - Food Processing and Packaging
Key concepts include:
Food processing and packaging enables efficient and effective food storage and distribution, reduce food waste, and enjoy a variety of food at times and places different from where and when it was grown.
Postharvest practices and technology help prevent food spoilage, and include washing, chemical/wax treatments, chilling, and storage in modified atmospheres.
Processing takes a raw commodity and makes a food product out of it.
Processing can alter the nutritional content of the food; nutrients added back to processed foods is called enrichment.
Some foods are fortified, a process by which a nutrient not normally present is added to the food.
Our consumption of high fructose corn syrup in this country is very high and started to rise about 45 years ago when we started producing corn surpluses.
Corn processing is a good example of the complexity and potential of food processing.
The corn “wet milling” process provides us with many products and a way to utilize the large amounts of corn that we grow.
We still utilize many simple, long-standing methods of food processing and preservation: drying, smoking, salting, freezing, and canning.
Food additives are an important component of food processing and include products produced by microorganisms on industrial scales.
Food packaging serves many important purposes such as containment, protection, and communication.
There have been many important inventions in food packaging that we take for granted, but that have fundamentally changed how we handle and distribute food.
While it serves important purposes, packaging creates waste and can pollute the environment.
There continue to be advances and innovations in packaging that help keep food fresh, convenient, and communicate information to consumers.
Processing and packaging require a large amount of energy in the food production process, about 1/3 of the total energy input to make food available to the consumer
Topic 7 - Adverse Consequences of Farming
Key concepts include:
2/3 of earth’s ecological systems are polluted, largely due to agriculture.
Agriculture contributes 9% to greenhouse gas emissions in the U.S., including CO2, methane and nitrous oxides. It's a major source for the latter two.
U.S. greenhouse gas emissions per capita and per GDP dollar have declined during the past decade.
More than 75% of U.S. water consumption is for growing our crops. And most of this is irrigation for crops to feed livestock.
Depleting aquifers and consequent land subsidence, and fertilizer runoff that creates dead zones are major impacts of agriculture on our water.
We are in a major mass extinction, the 6th wave of extinctions in the last 0.5 billion years, and the biggest since the dinosaurs went extinct. Human activities, including agriculture, are the principal cause of this.
Land degradation through erosion, physical and chemical damage, and desertification are major challenges in agricultural systems.
Conservation tillage (also called no-till or low-till) is an important farming practice to curb some of this damage.
Federal conservation programs are important for facilitating adoption of sensible farming practices to preserve our soils.
Topic 8 - Climate Change and Agriculture
Key concepts include:
The earth’s tilt, wobble and orbital eccentricity are influenced by the gravitational pull of other planets with defined periodicity (Milankovitch cycles). This influences the amount of solar radiation impinging the earth’s surface.
Mean global land and ocean temperatures have increased for the past 65 years.
Global warming only makes sense if you include anthropogenic forcings.
Solar radiation heats the earth, which radiates that energy in the infrared back into the atmosphere. Greenhouse gases capture that radiant energy and re-emit the energy in all directions to heat the atmosphere and surface.
Ice sheets appeared in the South Pole ~34 MYa, and the North Pole ~3 Mya. The latter grew and melted at 41,000-year cycles, with major ice ages every 100,000 years.
CO2, CH4 and temperature records from Antarctic ice core data are in perfect sync.
Ice and sediment cores and shells tell us a lot about our planet’s climate history. Low O18/O16 in sediment cores indicates warmer periods; a high ratio indicates colder periods.
We are in an interglacial period where CO2 levels should be declining and a period of cooling. We are not because observed data are just the opposite!
CO2 levels are at 407 ppm and increasing at 2 ppm per year.
Many climatologists believe that we should not exceed 450 ppm CO2, while others feel that we need to go back to 350 ppm.
Increasing temperatures will lead to increasing sea levels which will displace large numbers of people.
Decreasing CO2 emissions and combating climate change is a complex global problem that will require cooperative solutions.
Different greenhouse gases have different lifetimes in the atmosphere; CO2 has the longest.
Agriculture is an important contributor to greenhouse gases, especially methane and nitrous oxide.
North America (U.S.) has the highest per person emission of greenhouse gases.
The vast majority of U.S. electricity comes from coal and natural gas.
There are agricultural practices we can adopt and changes in your personal lifestyle to reduce CO2 emissions.
The U.S. position and policy on climate change are strongly influenced by politics.
Topic 9 - Genetic Engineering in Crops and Livestock
Key concepts include:
Biotechnology is a set of technologies in which a living organism or a system derived from one or more living organisms is directed to generate a product or a service. It has been around for a very long time.
Transgene technology is a relatively new biotechnology in which DNA molecules from native or foreign sources may be cut and joined to produce new DNA sequences and, when introduced into an organism, confer a new phenotype or trait.
Since their introduction in 1995, transgenic crops have almost continuously increased as the proportion of all plantings of each crop species.
The main transgenic traits in corn, soybean and cotton are the BT-insecticidal toxin and Herbicide Tolerance.
Humans have been eating “genetically modified” food since the dawn of agriculture with the development and selection of improved varieties of crops.
DNA is DNA, regardless of the source!
The Canadian regulatory system for “novel” plants, which encompasses all methods by which a plant’s DNA can be modified, seems to provide a more rational approach than other regulatory systems.
The regulatory system for GE plants in the U.S. and elsewhere is rigorous and thorough, as it should be.
Topic 10 - Human Nutrition
Key concepts include:
The macronutrients include carbohydrates, proteins, and fats.
There are 9 essential amino acids that must be obtained from our dietary protein intake and two essential fatty acids that must be obtained from our dietary fat intake.
Vitamins and minerals are essential micronutrients.
Examples of nutrient deficiency diseases include scurvy caused by lack of vitamin C, rickets caused by lack of vitamin D, anemia caused by a lack of iron, and pellagra caused by a lack of niacin.
Dietary Guidelines for Americans are published by the USDA and HHS every 5 years to guide dietary programs and policies.
Overall, Americans make food choices that do not align well with the Dietary Guidelines and healthy eating patterns. The percentage of Americans that meet Physical Activity Guidelines is low.
A healthy eating pattern includes nutrient-dense choices including a vegetables (from all groups), whole fruits, whole grains, lean protein sources (including seafood), low-fat or nonfat dairy and oils vs. solid fats.
A healthy eating pattern limits solid fats (saturated and trans fats), added sugars, and sodium.
It is important to shift to healthier food and beverage choices. Utilize MyPlate and read nutrition labels to pick a variety of nutrient-dense foods.
Topic 11 - Food Safety
Key concepts include:
Toxicity, hazard, and safety are important food safety terms that have different meanings.
Antibiotics increase weight gain in livestock. There is concern about the development of antibiotic resistance due to the large amounts of antibiotics used in CAFOs.
rBST increases milk production in dairy cattle and has been stated as safe by several food and health organizations. However, there is concern in the public because it is a product of genetic engineering.
Food additives are any substance added to food, and require premarket review and approval by the FDA unless they are GRAS by published scientific literature or historical record of safe use in food.
Certified color additives are synthetic colors added to food that undergo batch certification by the FDA
Foodborne illness can be caused by bacteria, viruses, prions and fungi.
Handwashing and proper food handling techniques such as thoroughly washing produce, cooking meat completely, and prompt refrigeration can help prevent foodborne illness.
Salmonella, Listeria, and E. coli can all cause serious and even potentially fatal foodborne illnesses.
The FDA, USDA, and EPA are all involved in ensuring food safety.
The CDC works with the FDA, USDA, and local health departments to investigate, contain, and prevent foodborne illness outbreaks
Some fungi produce toxins called mycotoxins. These mycotoxins can get into the food supply and be hazardous to human and animal health.
Aflatoxin, produced by Aspergillus fungi, is toxic to the liver and a potent carcinogen.
Aflatoxins can be found in nuts, corn, milk and other foods.
There was a serious outbreak of acute aflatoxin poisoning in Kenya in 2004 leading to liver complications and even death.
Chronic aflatoxin exposure can lead to liver cancer.
Topic 12 - Agricultural Economics Basics
Key concepts include:
The four major sectors of the food industry include the farm service sector, producers, processors, and marketers.
Most of our food is produced by the largest farms.
The processing sector creates value by converting raw agricultural commodities into food products the consumer wants.
The marketing sector creates value by changing the time and place of food.
In the U.S. we spend about 10% of our disposable income on food, which is the lowest in the world.
Supply relates to production and demand relates to consumption. Both supply and demand can be elastic or inelastic.
Net farm income in the U.S. has been fairly constant since the 1930s.
Crises in world food production and policy issues resulted in spikes in food prices in the 1970’s and 2000’s.
The "farm problem" in the U.S. refers to highly unstable farm incomes that tend to decline over time. Contributing factors are weather variability that creates large fluctuations in farm prices, and technological advances that result in overproduction.
With technology advances, our food production has outpaced population growth, at least for the time being.
Food demand is inelastic.
To deal with this farm problem the U.S. enacts policies and subsidizes agriculture.
Agricultural subsidies take different forms, and have both pros and cons.
The Ricardian principle of comparative advantage is fundamental to trade economics.
Technology fuels more efficient agricultural production and the globalization of markets, but also contributes to overproduction.
Global competition is a source of economic pressure on agriculture, but also a source of food in the future.
Governments enact tariffs and other trade barriers to protect their domestic markets.
Diversity and a strong technology base of California agriculture will help it sustain and thrive in the near future.
Topic 13- Immigration and Farm Labor
Key concepts include:
Global population = 7.6 billion and growing by 80 million a year.
California, and university towns like Davis in particular, have a disproportionate share of immigrants.
Demographics and corresponding economic inequalities drive migration, enabled by communication, transportation, and rights.
People moving from LDC to DC increase their income by over 10 fold.
In what demographic transition stage are we in here in the U.S.?
Economic development = labor shifts from agriculture to industry/manufacturing to services. Most rural-urban migrants stay within national borders (China and India), but some become international migrants (Mexico).
Rich countries subsidize agriculture, which employs a small percent of the population. Poor countries tax farmers, who constitute a large percentage of the population.
Most U.S. farmers are older, white, and farm their whole careers. Most U.S. farm workers are young, Hispanic immigrants who work in agriculture less than 10 years.
The majority of farm labor is involved in the production of high-value fruit, vegetable and horticulture crops.
Farm work is seasonal. This means that most farm workers make half of a typical minimum wage salary in a year. The best way for a farm worker to get ahead is to get out.
Due to low wages, part-time work, and lack of advancement, it is hard to retain workers in agriculture and to recruit U.S. citizens to work as farm workers.
Most farm workers in the U.S. are immigrants from poor countries and many are not legally authorized to work in the U.S.
The biggest union for farm workers is the United Farm Workers. It is not a very strong union because farm workers do not stay in farm work very long.
When farm labor costs rise the agriculture industry responds by increasing mechanization, decreasing the need for labor by reducing number of harvests, or importing commodities from poor countries.
Ag Jobs is a potential solution to labor shortages. This is a program where unauthorized workers could become U.S. citizens if they work in agriculture for a certain amount of time.
Comprehensive immigration reform includes increased enforcement to prevent further illegal immigration, legalization of some unauthorized immigrants currently in the U.S., and implementation of guest worker programs.
Comprehensive immigration reform has yet to pass in Congress, and as of this taping legislation on this issue has stalled.
Unauthorized immigration is a big issue for agriculture because half of agricultural workers are undocumented.
President Obama created the DAPA and DACA programs via executive action to allow some illegal immigrants to work legally in the U.S. Both programs have since been rescinded by the Trump administration.
The debate on illegal immigration has very polarized viewpoints. It is a complex issue with no simple solutions.
Topic 14 - Agricultural Pests and Impacts
Key concepts include:
Pests and diseases of crops and livestock have had profound impacts on societies since the dawn of agriculture.
These impacts are both direct (e.g., crop yield and food supply) and indirect (e.g., increased costs for processing, packaging, storage and transport).
The study of plant diseases led to important scientific discoveries that provided insights about animal and human diseases.
All three elements of the disease triangle must be in place for a plant disease to occur.
Localized potato crop failures in Ireland and northern Europe had occurred in the past–the pandemic beginning in 1845 was extraordinary in scope and impact.
Over 1 million people died from starvation and disease; 2 million emigrated to North America.
The Famine influenced politics and socioeconomics in Great Britain and the British Empire, and changed views about government responsibility for social safety nets and the demographics of North America.
Scientific study of late blight disease established the field of plant pathology and contributed to the germ theory for disease.
General principles learned from late blight management are widely applied for control of other plant diseases.
Citrus greening disease, aka Huanglongbing (HLB), is a devastating disease and a major threat to the citrus industry in the U.S.
The principles of integrated pest management are applicable in both conventional and organic production systems, with a goal of making farming more sustainable.
There is no evidence that organically grown food is healthier or more nutritious than conventionally grown food.
Invasive species are alien (exotic) species that reproduce rapidly, often displacing native species, and damage ecosystems.
Most commonly, but not always, invasives are introduced by human activity.
Invasive species cause enormous economic and ecological damages.
Examples of invasive plant diseases and pests.
Island environments are very vulnerable to invasive species.
Increasing globalization and trade has resulted in introduction and spread of invasive species.
Threats to agricultural biosecurity.
The example of foot and mouth disease.
Federal and state agencies are charged with dealing with introduced biological threats to agricultural and
natural systems and work to raise public awareness.
Topic 15 - International Agriculture; Concluding Remarks
Key concepts include:
795 million people worldwide are undernourished and many have vitamin deficiencies which cause disability and suffering.
Sub-Saharan Africa is the region hardest hit by hunger and malnutrition.
Children are particularly vulnerable to malnutrition and it can have life-long effects.
There are multiple causes of hunger and hunger and poverty can become a vicious cycle.
The majority of people in developing countries are involved in agriculture, so a focus of international agricultural development is helping developing countries to produce agricultural exports for trade.
The majority of food is produced by women in developing counties, but they have the least access to education.
International agriculture focuses on improving agriculture in developing countries through many methods.