1. Warm-Up Review What are the 5 components in soil?
Air and Water make up about _____ % of soil by volume.
What is an example of mechanical weathering?
What process transports sediments from one place to another?
During a rainstorm, which soil is more likely to have poor drainage: clayey or sandy soil?

2. Soil Issues and Conservation

3. Soil Degradation Soil used as a resources leads to degradation
Renewable resources BUT it takes years to form 1” of top soil
So, it must be protected, conserved
What are the main causes of soil degradation?
Crop production
Livestock production
Deforestation

4. Soil Issues
Erosion
Desertification
Salinization

5. Soil Erosion Erosion – wearing away of soil by wind or water
Causes – farming: loosens soil so it is more easily eroded by wind or water
Problems –
when topsoil wears away, crops cannot be grown
Sediments in rivers, lakes, etc.

6. The Dust Bowl

7. Soil Erosion The Great Dust Bowl 1930 Massive effort plowing of
prairies to plant wheat started
during WWI
Drought
Huge dust storms
Lead to the Soil Conservation Act (SCA), which established the Soil Conservation Service (SCS)- now known as the Natural Resources Conservation Service (NRCS)
Includes soil, and water quality and pollution

8. Desertification
Process by which land in arid or semiarid areas becomes more desert-like because of human activities
Causes – overgrazing, crops are planted too frequently, farming methods

9. Salinization
Occurs in arid and semi-arid regions where lots of groundwater is used to irrigate crops
High evaporation rate
Salts build up in soil over time as groundwater evaporates on surface
Plants have difficulty growing in salty soil

11. Soil Conservation Strategies
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Google: Soil conservation practices Minnesota

12. Contour Farming

13. Tilling the soil

14. No-till Farming

15. Ridge-till farming

16. Mulch-till farming (1)

17. Terracing

18. Cover crops

19. Windbreaks

20. Strip cropping

21. Wrapping Up:
Describe 3 methods of soil conservation used in agriculture
Provide one reason why soil conservation is important.
What region of the country would soil salinization be a problem?

22. Answers
1. No-till/reduced till, windbreaks, cover crops, contour farming, strip-cropping, terrace farming, agro-forestry
2. Top soil takes a long time to regenerate, if you lose topsoil, you lose nutrients, runoff a pollutant
3. Southwest and California (arid and semi-arid climates reliant on irrigation)

23. Soil Conservation Strategies
No till/reduced till agriculture
Leaves debris in field after harvest
Protects from wind/water; Decomposition recycles nutrients
Less CO2 emissions

24. Soil Conservation Strategies
Cover-Cropping
Planting a crop that covers the soil in fall, winter, and early spring
Legumes are sometimes used to restore Nitrogen to soil and improve fertility

25. Soil Conservation Strategies
Windbreaks or shelter breaks
Wind barricade; trees or fencing
Reduces soil loss from wind

26. Soil Conservation Strategies
Contour farming (low slopes) & Terracing (steep slopes)
Plowing & planting perpendicular to slope; large steps cut into hillside; Both control water flow

27. Soil Conservation Strategies
Intercropping & Agroforestry (alley cropping)
Multiple plant species in one area
Tall and short plantings; wind and water flow controlled

28. Soil Conservation Strategies
Silt Fencing at Construction sites
Keeps sediments on-site, less runoff

29. Farming Lingo
“Tillage” = plowing. Farmers plow their fields to expose the topsoil for seeds to be planted.
Ex: “No-till” farming does NOT plow the soil
“Yield”- the amount of a particular crop harvested per unit area: 50 bushels of corn/acre
“Acre”- 43,560 ft2, American farm unit
“Hectare”- 10,000 m2, Metric farm unit (>acre)
“Inputs”- resources put into growing a particular crop: fertilizers, pesticides, seeds, equipment, plowing