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28 Cards in this Set
- Front
- Back
What has been the trend in crop diversity over the past century? |
We have lost a lot of genetic diversity in plants. in the US, fruit and vegetable crops have decreased in diversity by 90% in less than one century. |
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Soil forms slowly and is a complex system. When decomposers break down organic molecules, they contribute a dark, spongy, an organic material to soil composition called? |
Humus |
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Erosion usually begins when____. |
The vegetation is removed either naturally or by humans |
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over irrigation in dry areas can cause ____. |
A buildup of salt in the soil to the point where it negatively affects plant growth. |
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What is the idea that one should not undertake new actions until ramifications of the action is well understood? |
Precautionary principle |
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What are effects of over nutrition? |
Chronic over nutrition can lead to diabetes and cardiovascular disease. |
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What is malnutrition? |
Occurs in people who consume adequate calories but lack essential nutrients, such as vitamins and minerals. |
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What is kwashiorkor? |
Occurs in people whose diets include ample calories but very low levels of essential amino acids and proteins. |
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What is under nutrition? |
People who regularly lack access to sufficient food calories. |
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What is marasmus? |
Inadequate caloric intake coupled with protein deficiency. |
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What are some characteristics of traditional agriculture? |
- Many crops grown together on small plots of land - Relies on human and animal power - Controls pests with natural pesticides and planting of multiple crops |
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What are some characteristics of industrial agriculture? |
- Controls pests with synthetic pesticides - Heavy use of synthetic fertilizer - Relies on fossil fuel powered machinery - Single crops grown on large plots of land |
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What is organic litter? |
This layer consists of plant residue atop the soil surface. on a forest floor, it may be leaves and twigs. in a field, it may be crop residue left after harvest. |
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What is topsoil? |
This layer consists of organic matter, humus, and inorganic minerals. it facilitates plant rooting, has high nutrient content, and holds water. |
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What is the eluviated layer? |
This layer loses minerals and organic matter to the layer beneath it. |
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What is subsoil? |
This layer accumulates minerals and organic matter leached from upper soil layers. |
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What is Parent material? |
This layer forms that base geologic material in a particular location; it is sometimes called bed rock. |
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What is conservation tillage? |
Farming practices that minimize disturbance to soil. |
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What is inter cropping? |
The practice of planting different crops in strategic arrangements within the same field. |
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What is crop rotation? |
Alternating the crops grown on a field from one season to the next. |
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What are shelter belts? |
Rows of trees or other tall plants grown at edges of farm fields in order to slow down winds.
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What is contour farming? |
Tilling sideways across a hillside to slow water running down the slope. |
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What is terracing? |
Creates level platforms for crops on steep hillsides in order to hold rainwater and reduce soil erosion. |
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Why is variety in crop plants important for "food security"? |
Varieties contain genes that, through conservational breeding, might confer residence to disease. |
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How does the conservaton reserve program (CRP) try to protect soil for future agriculture? |
The CRP pays farmers NOT to grow crops on land that is not very well suited for crop production. |
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Which of the following statements best describes the benefits of using organic fertilizers, also known as "green manures", such as dead plants? |
Organic fertilizers increased humus in soils. |
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Over time, pesticides become less effective. This is because ____. |
Pest can evolve defense against pesticides. |
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In regards to energy efficiency, aquaculture is ____. |
Incredibly energy efficient compared to harvesting fish from open waters. |