Soil, Agriculture, and the Future of Food Flashcards
(118 cards)
1
Q
What percentage of the largest universities/colleges in the U.S. have their own campus farm?
A
about 70%
2
Q
Food security
A
guarantee of adequate, safe, nutritious, and reliable food supply available to everyone at all times
3
Q
Food production ability vs. population (about)
A
increasing faster than population but may have an upper limit reached before population growth slows and much soil/arable land is declining or has been claimed already
4
Q
Undernutrition
A
fewer calories than the minimum requirement; affects nearly 800 million people
5
Q
What factors contribute to undernutrition?
A
poverty, political obstacles, regional conflicts/wars, inefficiencies in distribution, energy choices (i.e., when cropland is used for biofuels)
6
Q
Overnutrition
A
too many calories per day; leads to weight gain and possible health problems
7
Q
What major factor contributes to overnutrition?
A
increased availability of highly processed food that is high in calories (though nutrient-poor) and more affordable
8
Q
Malnutrition
A
shortage of the nutrients the body needs (proteins, lipids, vitamins, minerals)
9
Q
Agriculture
A
the practice of raising crops and livestock for human use and consumption (on cropland and rangeland, respectively)
10
Q
What percentage of the Earth’s surface is used for agriculture?
A
38% (more than any other human activity); globally 26% rangeland and 12% cropland; about 1/2 of all land in U.S. used
11
Q
Traditional agriculture
A
cultivating, harvesting, storing and distributing crops using human/animal muscle power, hand tools and simple machines; typically involves planting polycultures
12
Q
Industrial agriculture
A
large-scale mechanization and fossil fuel use, replacement of animals by machinery, increased irrigation, and the introduction of synthetic fertilizers and chemical pesticides in agriculture; now on 25% of all cropland; decreases food prices; involves monocultures for organization and efficiency
13
Q
Polyculture
A
a mix of different crops
14
Q
Monoculture
A
one type of crop (increases the risk of diseases and pests due to genetic similarity; narrows the world’s diet and decreases diversity as 90% food now from just 15 crops and 8 livestock species)
15
Q
Seed banks
A
institutions that preserve millions of seed types to conserve wild/indigenous varieties of crops in case their genes are needed later (also protects them from gene exchange with genetically modified varieties)
16
Q
Green Revolution (later 20th century)
A
a movement aiming to increase food quantity and quality especially in developing countries using new technology, crop varieties and farming practices
17
Q
Relationship between energy used for agriculture and total area cultivated (1900-2000) + effects
A
energy up 80x while area only up 1/3 due to industrialization; decreased pressure to cultivate more varieties and increased food production while low area increase meant preserved habitats and biodiversity; increased the use of fossil fuels, water, inorganic fertilizers, and synthetic pesticides which increased pollution and erosion + decreased soil/water quality; suitable land for agriculture is finite so efficiency must be increased (industrial agriculture is in some form necessary)
18
Q
Sustainable agriculture
A
maintains soil, water, pollinators, and genetic diversity for long-term agricultural production; tries to mimic the cyclical nature of ecosystem function where negative feedback loops stabilize it; aims for low-input of fossil fuels, water, pesticides, fertilizers, growth hormones, and antibiotics; decreases production cost by letting nature provide ecosystem services (e.g., by creating habitats for insect predators)
19
Q
Soil
A
a mixture of disintegrated rock, organic matter, water, gases, nutrients and microorganisms; 50% minerals, 5% organic matter, rest = pore space taken up by air or water (organic includes living + dead + decaying)
20
Q
Process of soil formation
A
parent material of lithosphere is exposed to the effects of the atmosphere, hydrosphere and/or biosphere and breaks down by weathering; biological activity then turns to soil through deposition, decomposition and accumulation of organic matter
21
Q
Bedrock
A
a continuous mass of solid rock that makes up the Earth’s crust
22
Q
Humus
A
a soil-like mixture resulting from partial decomposition of organic matter mixing with mineral matter; still contains complex compounds that have to be broken down for plants to use them; holds moisture well
23
Q
Rate of soil generation
A
one inch may take 100s-1000s of years; renewable but not regained quickly
24
Q
Soil horizons
A
distinct layers of the soil that form as wind, water and organisms move particles of it
25
Soil profile
a cross-section of all the soil horizons from the surface to bedrock
26
Order of soil horizons (top to bottom)
O (organic/litter), A (topsoil), E (eluviated/leaching), B (subsoil), C (weathered parent material), R (parent rock)
27
All soils have all 6 soil horizons.
false
28
Leaching
method by which minerals are transported down through the soil; solid particles are suspended or dissolved in a liquid; in some soils minerals do this so rapidly that plants can't access the nutrients carried; can then enter groundwater supply
29
Which soil horizons have the most living organisms?
O and A horizons
30
Which soil horizon is the most nutritive for plants?
A horizon (has organic and mineral content; rich in humus so dark color, loose texture + great water-holding capacity); crucial for agriculture but unsustainable use = decreased organic matter, fertility and water
31
Effects of climate on soil characteristics
more rainfall = more leaching, higher temperature = faster decomposition and nutrient uptake (both decrease topsoil quality); why rainforests lose fertility so quickly when cleared for agriculture
32
Swidden/slash-and-burn agriculture
involves burning the vegetation in an area before growing crops there in order to release the nutrients that are largely held within them; depends on short-term use of the land (let it grow back and move somewhere else within a year or a few); conversion of cleared plots to pasture instead increasing, degrades soil
33
Soil fertility in North American grasslands
less rainfall and steady decomposition = repeated use for farming with little fertility loss if soil loss is prevented
34
Irrigation
the artificial provision of water to support agriculture; used to maintain yields and convert dry land to fertile land
35
Rate of irrigation
has increased with industrialization; 70% of withdrawn freshwater is used on crops; can dry up aquifers, rivers and lakes
36
Waterlogging
when overirrigation causes the water table to rise enough to drown plant roots
37
Salinization
the buildup of salts in surface soil layers; in dry areas evaporation from the A horizon can pull water upwards and leave salt behind there, thus decreasing productivity; affects 20% of irrigated cropland
38
Reduction of water use in irrigation
done by matching crops with climate, collecting rainwater for use and using technology; government subsidies in dry areas make extensive irrigation artificially inexpensive on high-water crops but lots of water is lost through evaporation; plants only use about 40% of the water applied globally as the rest evaporates or is soaked too deep into the soil, but drip irrigation systems target plant roots and increase efficiency to 90%+
39
Fertilizer
provides nitrogen, phosphorus, potassium and other essential nutrients to plants where leaching and uptake has removed them from the soil; can be inorganic (mined or synthetically manufactured) or organic (from remains or wastes of organisms, including manure, crop residues, fresh vegetation/"green manure" and compost)
40
Compost
produced when decomposition breaks down organic matter in a controlled environment ("closed-loop" systems recycle waste)
41
Reduction of excessive fertilizer use
need to target plant roots, as with water; may add to drip irrigation water, inject with seeds (as in no-till farming), monitor levels and add sparingly, or plant buffer strips of vegetation on field edges to capture nutrient runoff
42
Precision agriculture
uses technology to precisely monitor crop conditions and needs + resource use to maximize production and minimize waste
43
Pros and cons of organic fertilizer
provides nutrients as well as organic matter that improves soil structure, nutrient retention and water retention; excess means excess nitrogen/phosphorus that may also enter runoff and cause pollution; might be best to use organic and inorganic fertilizers together
44
Soil degradation
a decrease in the quality and productivity of soil; especially happens in dry areas
45
Population increase vs. soil degradation per year
increase of 80 million people, loss of 5-7 million ha productive cropland (caused by erosion, nutrient loss, water scarcity, salinization, waterlogging, chemical pollution, structure and pH changes, and organic matter loss)
46
Effects of erosion and deposition on soil
both create soil but erosion on a local level happens faster than formation and thins the most important layer for life (topsoil); increases with angle of land, precipitation and less vegetation
47
Movement of soil by human activities
10x more than all natural processes on Earth combined
48
United States soil loss per 1 ton of grain
5 tons of soil
49
Drylands
includes arid and semi-arid environments; 40% Earth's surface; prone to desertification
50
Desertification
a form of land degradation where more than 10% productivity is lost (due to erosion, soil compaction, forest loss, overgrazing, drought, salinization, climate change, or water loss but mostly erosion)
51
Overgrazing
result of too many livestock; prevention of plant biomass regrowth when too much is removed (eaten) or hooves churn the soil and expose it to erosion; positive feedback loop where erosion makes regrowth even harder which worsens erosion; can allow non-native plants to take over; trampling also causes compaction and soil structure change so water and air are less able to penetrate and roots cannot expand; causes as much degradation as cropland and more desertification
52
Effects of movement of farmers to the Great Plains (19th-20th century)
introduction of wheat and cattle --> loss of native grasses and increased erosion; worsened by drought in the 1930s (travelled up to 2000 km, blackened rain/snow)
53
Dust Bowl
originally referred to the region in the southern Great Plains most affected by drought and dust storms, now refers to the drought event in general
54
Responses to the Dust Bowl
increased soil conservation research, established the Soil Conservation Service (SCS, now the Natural Resource Conservation Service) to help individual farms
55
Crop rotation
practice of alternating the type of crop grown in a given field from one season/year to the next; returns nutrients to the soil, breaks disease cycles, decreases erosion that occurs without cultivation and decreases pests adjusted to the previous crop
56
Nutrient-replenishing crops
legumes (plants with special bacteria on their roots that fix nitrogen) and temporary cover crops (prevent erosion while adding nutrients)
57
Contour farming
practice of plowing furrows sideways on a hillside perpendicular to the slope and following the land contour; slows runoff and catches soil that would otherwise be eroded by water (may also add buffer strips of vegetation to the borders of a field or stream for the same purpose and to prevent pollution)
58
Terracing
practice of turning especially steep terrain into a series of steps to allow cultivation without much erosion; terrace = level platform but may have raised edges, cut into hillside
59
Intercropping
practice of planting different crop types in alternating bands; increases ground cover more than one type, decreases pests and disease and can add nutrients if legumes (or similar) are one type used
60
Shelterbelts (windbreaks)
rows of trees or other tall plants placed on field edges to slow wind and decrease erosion; also provide fruit, wood and habitat for wildlife
61
Conservation tillage
practice of reducing tilling/plowing; tilling aerates and nourishes the soil (by pushing weeds and crop residue into it) but also exposes it to erosion
62
No-till farming
farming without tilling or plowing at all; leaves the soil covered with plant material, so planting the next crop involves cutting a thin and shallow groove into the soil, adding the seeds, and covering them with a no-till drill tool; decreases erosion, increases organic matter content and increases water-holding potential; used 1970s in South America to prevent erosion and also decreased labor/fuel costs + increased profit
63
Proportions of U.S. land using conservation tillage and no-till farming
40%; 25%
64
Proportion of the income of an average U.S. farmer from government subsidies
1/5
65
Government support for farmers vs. sustainability
subsidies said to compensate for bad weather years, but also encourages cultivation of land otherwise not farmed, produces more food than needed, decreases prices for other producers, and promotes unsustainable practices (alternative = farmers buy insurance for short-term problems); provisions to conserve soil in farm bills every 5-6 years that require conserving practices before subsidies are given; Conservation Reserve Program (CRP) from 1985 Farm Bill pays farmers to stop using highly erodible land and instead create reserves with grasses and trees (estimate $1 investment = 1 ton of topsoil saved + increases income, water quality and habitat), capped 2017 at 10 million ha; UN promotes sustainability with Food and Agriculture Organization (FAO)
66
Pest
an organism that damages valuable crops
67
Weed
a plant that competes with crops
68
Consequences of clustering crops together (especially monocultures)
insects, fungi, viruses, rodents and weeds may thrive; can adapt to specific crop and move through an entire field of it; natural predators can be limited + farmers often resort to chemicals
69
What do pesticides include?
fungicides, herbicides and insecticides
70
Pesticide levels in the U.S.
4/5 of applied used on agricultural land, quadrupled use since 1960 (leveled off in industrialized nations but increasing in developing ones)
71
What is one factor that leads to pesticide resistance?
most insects, weeds and microbes come in huge numbers so the likelihood of resistant genes (which allow metabolism and detoxification) is high
72
Biological control (biocontrol)
controlling pests and weeds with organisms that eat or infect them; more sustainable than pesticides; also may be developed into genetic modification where the genes that produce proteins that affect pests/weeds are isolated and engineered into plants; riskier considering introduced organisms are harder to control and can become invasive in the area or in other areas to which the organism can travel
73
Integrated pest management (IPM)
uses multiple techniques to control pests since chemical and biological means both have their own risks; may involve close monitoring of pest populations, biocontrol and synthetic chemicals, habitat alteration, crop rotation, transgenic crops, alternating tillage and mechanical pest removal
74
Pollination
the process by which male sex cells of a plant (pollen) fertilize the female sex cells of a plant
75
Pollinators
animals that move pollen from one flower to another
76
Adaptation of flowers
"designed" to attract pollinators with sugary nectar, protein-rich pollen, sweet smells and bright colors
77
Crops that need pollinators
many grain crops come from grasses and are wind-pollinated but 800 others rely on pollinators
78
Causes of pollinator decline
industrial agriculture, pesticides (even in lawns and gardens), habitat + flower loss and invasive parasites/pathogens
79
Apis mellifera honeybees and pesticides
increased pesticide exposure has shown physiological harm, increased mortality, and altered behavior; studies treated the hive as a "super-organism" (since the colony depends on collective survival) and measured exposure during a typical agricultural season (since most studies only measure one pesticide at a time although many are used at once in reality); pesticides can concentrate in a beehive since forager bees move over a large area and some food containing it is stored in cells near larvae ("beebread"), is converted into a protein- and calorie-rich secretion by nurse bees for the larvae and essentially "bioaccumulates"; also noted "queen events" or instances where the queen died/was killed by workers when something was off (with her pheromones) as an increase tends to mean an increased chance of colony collapse; found a correlation between collapse and the number of pesticides but not their concentration + applied to fungicides as well
80
Colony collapse disorder
occurs when the majority of worker bees are lost and the rest of a hive is endangered; caused by many stressors and has killed 1/3 of all honeybees in recent decades; combatted through planting more wildflowers and shrubs for refuge and food + creating nesting sites + decreasing pesticide use
81
Effects of increased wealth and global commerce on animal products
causes an increase (meat production x5 since 1950, per capita consumption x2); comes with the demographic transition
82
Which animal is used the most for food?
chickens
83
Energy efficiency of animal-based food
only 10% of the energy moves up to the next trophic level with meat (most of the rest used for cellular respiration); larger ecological footprint; some animals convert their feed to products more efficiently than others and some need more land/water than others
84
How can the impact of different animal products be measured?
look at the amount of land and water needed for 1 kg of animal products and the greenhouse gases released in the process of obtaining those products
85
Impact of animal-based products in terms of food input (least to greatest)
milk, chicken, eggs, pork, beef
86
Impact of animal-based products in terms of land use (least to greatest)
chicken, eggs, milk, pork, beef
87
Impact of animal-based products in terms of water use (least to greatest)
eggs, chicken, pork, milk, beef
88
Impact of animal-based products in terms of GHG emissions (least to greatest)
chicken, eggs, pork, milk, beef
89
Feedlots
AKA factory farms or concentrated animal feeding operations (CAFOs); huge warehouses/pens to give energy-rich food to animals at a very high density; contrasted with how traditional agriculture keeps livestock near the homes or on grasslands with herders/ranchers; produce 1/2 the world's pork and most poultry; increases economic efficiency and production, decreases grazing impacts and more affordable; require 45% of global grain to feed animals which increases its price and decreases food security + waste can pollute water + need heavy antibiotics to control diseases which leads to resistance by microbes + a major animal rights (and welfare) issue + a big source of GHG emissions
90
"Free range" animals
posed as an alternative to feedlots but the USDA may only require ex. access to the outdoors (the definition is vague) + costlier and lower incentive
91
Effects of increased demand and better technology on fishing
causes overharvesting of most marine fisheries and decreases wild populations of fish
92
Aquaculture
the cultivation of aquatic organisms (including aquatic plants) for food in a controlled environment; may live in open water in net-pens, ponds or tanks; fastest-growing form of food production; provides 3/4 of the freshwater fish and 2/3 of the shellfish eaten
93
Benefits of aquaculture
decreases population pressure, consumes fewer fossil fuels, offers a safer work environment and is energy-efficient compared to standard fishing; up to 10x the fish/unit area than harvesting from the continental shelf or 1000x that from the open ocean
94
Downsides of aquaculture
produces a lot of waste/potential pollution from the organisms kept and uneaten food; feed is often grain or fish meal which worsen food security issues and decrease wild populations further, respectively; organisms can escape to nonnative ecosystems and spread disease or outcompete native species (+ introduce genetically engineered DNA makeup to wild species)
95
When were the benefits of genetic modification when it was first widely used in the 1980s and 90s?
increased nutrients, increased efficiency and lower environmental impacts
96
Genetic engineering
the process by which scientists directly manipulate an organism's genetic material in the lab by adding, deleting or changing DNA segments
97
Genetically modified organisms (GMOs)
organisms genetically engineered with recombinant DNA (or DNA patched together from several organisms); receive desired traits such as rapid growth, disease resistance or high nutritional value
98
Transgenic organism
contains DNA from another species
99
Transgenes
genes that have been moved between species
100
Process of creating recombinant DNA
isolate plasmids from a bacterial culture --> remove the gene of interest from another organism --> insert the gene to form the recombinant DNA --> have the bacteria reproduce and generate many copies of the gene --> transfer the gene to the target organism
101
Biotechnology
the application of biology to create products derived from organisms; helps with (for example) the development of medicine, pollution cleanup, understanding the causes of cancer, dissolving blood clots, and beer/cheese production; different from artificial selection/selective breeding (combines DNA from separate species rather than the same species, deals with whole DNA and creates combinations rather than letting them naturally occur)
102
Statistics on genetically modified crops
now on 10% of the world's cropland; in the U.S. about 90% corn, soybeans, cotton and canola have GM strains; over 70% processed foods in the U.S. contain GM ingredients; soybeans = 1/2 (51%) of the world's GM crops while corn = 30%, cotton = 13% and canola = 5%; half of all grown in developing nations; worldwide 4/5 soybeans, 3/4 cotton, 1/3 corn and 1/4 canola = transgenic
103
Goals of GMOs
drought resistance in arid regions and high yields to feed more using the same amount of land as a standard crop; would also decrease irrigation and malnutrition; herbicide-resistance = promotion of no-till farming and insect-resistance = less pesticide use (cost and desire for profit lower incentives for corporations)
104
Actual findings on relationship between herbicide/pesticide use and GM crops
insecticide use decreases but herbicide use increases (weed resistance is increasing)
105
Precautionary principle
the idea of not undertaking a new action until the ramifications are well-known; may be applied to GMOs (would have to compare one-by-one to conventional foods and the companies making GM foods tend to control the research done + the effects of interbreeding with wild relatives are yet unknown, but some think there is enough research already and the benefits outweigh the risks)
106
Ethical and economic concerns of GMOs
some find the modifications immoral; concerns about a few major corporations that develop the technology controlling global food supply (namely agrobiotechnology companies - Monsanto, Syngenta, Bayer CropScience, Dow, DuPont and BASF) which would also threaten family farmers; legal actions have been taken by corporations, which are favored by the courts, against smaller farmers on the basis of their patented transgenes/GM crops being found within their fields even if it was due to contamination from nearby farms; many countries are more uneasy about GM crops (their import to Europe was blocked from 1998-2003 until the World Trade Organization enforced it) and have requirements that the food be labeled (some believe it is their right to know, may decrease sales)
107
Organic agriculture
a form of agriculture that doesn't use any synthetic fertilizers, insecticides, fungicides or herbicides; a type of sustainable agriculture
108
History of organic food labels in the United States
U.S. Organic Food Product Act (1990) set product standards and facilitated sales; 2000 USDA issued the criteria necessary to certify as organic (put into effect 2002)
109
Benefits of organic agriculture
lowers input costs, increases profit for higher-value produce and decreases chemical pollution and soil degradation; eventually the input and product costs make it at least as profitable as conventional farming
110
Risks of organic agriculture
have to meet the standards set for 3 years before certified and able to sell the food at higher prices; may have lower yields
111
Price and availability of organic products
tend to be 10-30% more expensive, sometimes 2x the price; availability still increasing since many people are willing to buy them
112
Statistics for organic sales
80% of Americans buy products at least occasionally; make up 5% all food sales, up from 1% in 1998; worldwide increased 5x from 2000-2016
113
Statistics for the development of organic agriculture
takes up less than 1% agricultural land worldwide but increasing; 2/3 in developing nations; amount has tripled in the U.S. since the 90s with devoted acreage quadrupled; 5%+ agricultural land in the EU
114
Examples of helpful government policies for organic agriculture
U.S. 2014 Farm Bill lowered organic agriculture certification costs; EU financially supports the conversion to organic
115
Farmers' markets
locations where consumers can buy meats and fresh produce in season from local producers; often feature a wide choice of organics and unique varieties not found in supermarkets
116
Benefits of farmers' markets
lower the amount of fossil fuels for transport and the need to treat produce with chemicals to preserve it during travel; support smaller farmers who need it
117
Community-supported agriculture (CSA)
a partnership between consumers and local farmers where consumers pay farmers in advance for a share of their yield and usually receive a weekly delivery of produce; guarantees income upfront to invest in the crops + helps with unpredictable weather + better than a simple loan
118
Factors that help with sustainable food practices at universities/colleges
campus farms, organic food, trayless dining halls (decreases water used for dishwashing and how much students take and eat/waste), composting, reusing waste oil as biodiesel
