Agriculture and Soil Flashcards
(43 cards)
How many crop species are there worldwide?
3000
How many crop species in the U.S.
200
AquaCulture
Production of food from aquatic habitats
Mariculture
Production of food from ocean habitats
Most Genetically Modified Crops are engineered to resist what?
Herbicides
What is soil
a thin part of earth’s surface that is a layer of mineral and organic matter
Soil produces and stores what?
Plant nutrients
What part of earth’s surface is soil in
lithosphere
How much inorganic material is in soil
45%
What does the inorganic material in soil make up
1/2 is small pieces of weathered rock fragments and 1/2 is small particles of minerals
How much organic material is in soil
5%
What does the organic material in soil make up
living and dead plants and animals and humus
What does humus do?
improves soil fertility
What is half the volume of soil
pore space
How is soil air different from atmospheric air?
1) soil air is always saturated since its surrounded by water
2) soil air is rich in carbon dioxide and poor in oxygen
What are the three functions of soil water
1) dissolves all nutrients making them available to plant roots
2) enables chemical reactions
3) Leaching; plant nutrients carried below plant roots
How does most water get into soil
By infiltration of precipitation
What is soil erosion
natural process initiated by both wind and water
Soil Erosion sequence
1) Rain erosion
2) sheet erosion
3) rill erosion
4) gully erosion
Methods to minimize soil erosion
1) Reducing erosion on slopes
2) Use ground cover
3) reducing tillage
Methods of reducing erosion on slopes
1) crop rotation
2) strip cropping and contour plowing
3) terracing
Methods of using ground cover
1) intercropping
2) crop residue
3) cover crops
4) mulch
Methods of terracing
1) minimum till
2) conservative till
3) no till
Problems with irrigation?
1) poor efficiency
2) over-watering
3) salinization
4) increases erosion
5) depletes aquifiers
