Unit 7: Agriculture // Visuals

Animation(s)

Pesticides affect natural predators: Numbers of natural herbivore predators are greatly reduced with pesticide use, allowing the pest population to grow at tremendous rates. View animation
Results of decreasing pesticide use: Pesticide use was dramatically decreased in the 1990s but overall rice production yields did not decrease. View animation
The effect of pesticides on trophic levels: Pesticide use kills organisms at all trophic levels, except the eggs of pests, resulting in a pest population explosion. View animation

Photograph(s)

Chopping and disking mustard green manure, Washington state, 2003: Farmers have practiced green manuring for centuries, but the technique has become more sophisticated with growing understanding of soil ecology, plant biochemistry, and nutrient cycling. View image
Confined hog production facility: Large hog farms may house 10,000 or more hogs indoors for their entire life spans. On many U.S. farms, breeding sows are kept for weeks at a time in individual crates too narrow for the animals to turn around. View image
Conventional and golden rice: Along with wheat, maize (corn), and potatoes, rice is one of the world's most important staple foods. These foods contain widely varying levels of many important micronutrients. Golden rice is designed to eliminate one deficiency by producing vitamin A in its grains. View image
Feedlot cattle: On a feedlot, young beef cattle are grown to market weight on a diet that consists primarily of grain. Cattle that are fed grain reach market size at about 14 months of age, compared to 18 to 24 months for grass-fed beef, but raising cattle on grain is much more energy-intensive. View image
Gathering insects for identification during IPM training, Indonesia: Field schools advance IPM programs by enabling farmers to see and compare the results of various pest control methods. View image
Guano deposits on Gardner Pinnacles, Laysan Island, Hawaii, 1969: Seabird manure, a rich source of nutrients, has been used as fertilizer for centuries. View image
Irrigation in the heart of the Sahara: A small settlement just north of the border between Egypt and Sudan taps an underground aquifer to support farming in the desert. Each dark spot is an irrigated crop circle about 1 kilometer across. View image
Rice varieties: Dwarf plants have relatively thick stems and are less likely to lodge (fall over under the weight of the grain they carry). A low-tillering plant is one with fewer stalks at the bottom. View image

Graphic(s)

DDT accumulation in the food chain: Use of DDT was banned in the United States in 1972 because of its persistence, its tendency to bioaccumulate, and its adverse impacts on reproduction, especially in birds. View image
Distribution of climate and soil/terrain constraints by region: Climate, soil quality, and terrain significantly limit where crops can be grown productively. Some of these constraints can be mitigated with inputs like irrigation and fertilizer, and with techniques that manage land resources on a sustainable basis. View image
Geographic distribution of potential biomass energy crops: Potential energy crops could be grown in many areas of the United States that are unsuited for agriculture, providing new cash crops. View image
How plants grow: Photosynthesis, respiration, and transpiration drive plant growth and development. View image
Simplified model of a primary cell wall: Cellulose, hemicellulose, and lignin (not shown) are closely associated in plant cell walls. This structure makes it difficult for glucose molecules to be fermented into fuel. View image
U.S. certified organic acreage: Organic farming accounts for a small fraction of land under cultivation worldwide, but interest in organic methods is rising. Organically grown products typically earn significant market premiums over conventional crops. View image
World cereal production: Cereals are the primary source of animal feeds and non-meat calories for humans worldwide. View image
World food production, 1961-1996 (measured as the sum of cereals, coarse grains, and root crops): World food production grew at unprecedented rates in the second half of the 20th century, increasing available food supplies in most regions except for sub-Saharan Africa. View image

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