Soil and Agricultre

1. Soil and Agricultre Environmental Science Chapter 12

2. THE central Case • Possible Toxic Maize in Oaxaca, Mexico How can we balance our growing demand for food with our need to protect the environment??

3. Section 1 • Objectives • 1. Explain 3 processes by which soil forms. • 2. Describe the horizons that make up a soil profile. • 3. List the four characteristics used to classify soil.

4. Section 1 • What percent of the Earth’s land surface do you think is used for agriculture? • How would you describe the difference between soiland dirt?

5. Section 1 • __________ : a complex plant-supporting system made up of ________________________, ___________________________________, _________, ____________, ______________, and ________________________. • Soil is a __________________ resource. • Figure 1

6. Section 1 • Soil forms through __________________, ______________, and __________________. • Soil consists of 45 % _________________, 5% ____________________, and 50% ____________________________.

7. Section 1 • __________________________; the geological material in a particular location – may be made up of ______________, rock or sediment deposited by ____________, ________________, ___________, ____________, ______________, or _________________. • ______________: the continuous mass of solid rock that makes up the Earth’s crust

8. Section 1 • __________________ is the first process in soil formation. • It describes the ____________ and __________ processes that break rocks and minerals into smaller pieces. • ________________: the natural break up of rock without chemical reactions. ____________ and ____________ are the 2 main causes. But, ___________________, _____________, and _____________ also contribute.

9. Section 1 • ________________: breaking down rocks by chemical processes.

10. Section 1 • _____________________: the dropping of eroded material at a new location. • _______________________: the breakdown of organic material. • ________________: dead leaves and vegetation. • _____________: partially decomposed organic mater. • Both add to the fertility of the soil.

11. Section 1 • ____________________: the distinct layers of soil. • ___________________: the cross-section of all the soil horizons of a specific soil. • There are 6 major soil horizons: O, A, E, B, C, and R • Soils differ from location to location, and few soils have all 6 horizons. • Figure 4

12. Section 1 • A horizon: ______________. This horizon has the most plant nutrients available. • Gets much of its potential from the O horizon, _____________, • The A horizon is fragile. It must be protected in order for it to last.

13. Section 1 • As you move lower through the horizons the particle size _____________. • E horizon: ___________. • Particles suspended in liquid are transported to another area

14. Section 1 • Soil Characteristics • ____________, ______________, _____________, _________ • _____________ • Dark soil: • Pale soil:

15. Section 1 • __________________ • Based on particle size • __________: particles 0.002 mm or smaller • __________: particles between 0.002-0.05 mm • __________; particles between 0.05-2 mm

16. Section 1 • Sand particles do not stick to each other • Clay particles do stick to each other • Most soils are a combination of clay, silt, and sand. When there is a relatively even mixture of the three the soil is called ______________.

17. Section 1 • The texture of the soil influences its _________________; how easy it is to plant in and harvest from. • It also determines its _________; the size of the air spaces between the particles.

18. Section 1 • Structure Describes the arrangement of the soil particles • pH • Can be either ____________ or ______________.

19. Section 2 • Objectives • 1. Describe some practices that can lead to soil erosion and some that can prevent it. • 2. Identify the causes and effects of desertification. • 3. Discuss the activities of US and international agricultural organizations. • 4. Explain how irrigation and pesticide use can cause soil pollution.

20. Section 2 • Studies show that the most productive soil is ____________, with a _____________ pH.It is _______________, contains _____________, and holds _____________. • Human activities can cause ___________, __________________, and ____________ that make soil less productive.

21. Section 2 • The deterioration of the soil characteristics needed for plant growth or other ecosystem services is called ___________ ________________. • This can be devastating to ecosystems. • Let’s look at how this can occur……

22. Section 2 • Erosion • Can be a problem because it usually occurs ____________ than the rate at which soil is formed. • Erosion can also ____________ soils • Ex:

23. Section 2 • Today, human activity cause more erosion than do natural events. • More than ___________acres of the world’s croplands now suffer from erosion and other forms of soil degradation. • Reasons: _______________________, ______________________, and ________________________.

24. Section 2 • In the US erosion rates are now declining due to _______________ _______________. • Figure 7 – Farming Practices • ______________________: planting different crops of mixed arrangements. • ____________________: alternating crops grown in a field • ____________ ______________

25. Section 2 • ______________________ _________________: rows of trees of other tall perennial plants that are planted along the edges of fields to slow the wind. • _________________: The turning over of soil before planting. Makes soil more susceptible to erosion. • _____ ___________ ______________: planting right back into a field with the residue left from previous crop. • ______________-_____________: turning the soil slightly.

26. Section 2 • _________________: transforms steep slopes into a series of steps like a staircase • ____________ ___________: plowing sideways along a hillside allowing the land to conserve soil and water. • Ranching Practices • ___________________: when too many animals eat too much of the plant cover, impeding regrowth. • Effects: __________________, _________________, and _____________.

27. Section 2 • Forestry practices • _____________ ____________ can lead to severe erosion. • _____________ __________: lead to less erosion • Desertification • The loss of more than 10% of productivity due to erosion, soil compaction, forest removal, overgrazing, drought, salt buildup, climate change, depletion of water.

28. Section 2 • Some scientists suggest _______ of Earth’s land area is affected by desertification. • THE DUST BOWL • In the late 1800’s and early 1900’s settlers in OK, TX, KS, NM, and CO began tilling up the grasslands. Between _______ and ______ the farmed area of the Great Plains increases ______%

29. Section 2 • Soil Conservation Policies • In response to the ________ ________ soil conservation practices were being explored • ______: the U.S. Congress passed the ________ _________________ ______ establishing the _______ _________________ _________ (SCS) • In _______ it was renamed to ______ _________ ______________ ___________ and was expanded to include __________ __________ and _______ _____.

30. Section 2 • U.S.Policies: • ____________ _________ __________ (CRP) was part of the _________ farm bill requiring farmers to put in place a conservation plan before they got their subsidies. • It is estimated the for each dollar invested in this program saves nearly 1 ton of topsoil.

31. Section 2 • International Policies: • ________ ______ ____________ (FAO) • ____ _____ ____ ____ (FARM)

32. Section 2 • Soil Pollution • _________________: providing water to crops other than precipitation • ________________: the build up of salts in upper soil horizons. • Can be made worse through irrigation • How? • Solutions:

33. Section 2 • Pesticides • Residual chemicals could remain in the soil for long periods of time and may be toxic to humans. • Chemicals can get into the groundwater contaminating it • We are not sure of the long-term effects of some pesticides. • Broad-spectrum pesticides may kill a wide variety of insects, some of which may be helpful to the soil.

34. Section 3 • Objectives • 1. Discuss the beginnings of agriculture • 2. Explain the importance of industrial agriculture and the green revolution • 3. Identify different types of pest control • 4. Explain the importance of pollinators to agriculture

35. Section 3 • Agriculture began about ____________ years ago when a warmer global climate allowed humans to plant seeds and raise livestock. • This change was called the _________ ___________. • Figure 13 • ____________ ____________: planting seeds only from plants whose fruit has desirable qualities.

36. Section 3 • ____________ ______________: faming with hand tools and worker animals without the use of fossil fuels. • Soon bigger fossil-fueled machines replaces worker animals. • _____________ ____________ replaced traditional agriculture.

37. Section 3 • ________________ ________________: • ________________________: large areas planted with a single crop. • Benefits: • Drawbacks:

38. Section 3 • ___ _________ ______________: a movement in the mid-to late 1900s in which scientists from developed countries introduced new technology, crop varieties, and farming practices to the developing countries. • Technology: • Environmental Effects:

39. Section 3 • _______: something that damages plants that are valuable to us. • _______: a plant that competes with our desired crops. • How do we control them? • __________________ • _________ ________ __________: controlling pests and weeds with organisms that eat or infect them • Figure 16

40. Section 3 • Biological Pest Control • ______: Bacillus thuringiensis– a naturally occurring soil bacterium that produces a protein that kills many caterpillars and the larvae of some flies and beetles. • ________________________: combining the most useful aspects of chemical and biological pest control

41. Section 3 • Pollinators: • _______________: The process by which male sex cells of a plant (pollen) fertilize female sex cells of a plant. • Some plants are pollinated by the wind, while others rely on _______________: animals, such as insects and hummingbirds that pollinate flowers.

42. Section 3 • Pollinator populations have ______________. • Ex: _______________ • Ex: _______________

43. Section 4 • Objectives • 1. Explain why the world needs to grow more food and grow it sustainably. • 2. Discuss genetically modified food • 3. Describe the advantages and disadvantages of industrial food production. • 4. Discuss sustainable agriculture

44. Section 4 • Each year the Earth gains 75 MILLION people and LOSES 12-17 MILLION acres of productive cropland. • In addition ________ _____, or land suitable for farming is running out. • Since 1961 we have increased our food production by _________________, ___________, _________, ________, ____________, ______________. • Despite these efforts ____________ people globally are still hungry.

45. Section 4 • _________ ____________: the guarantee of an adequate and reliable food supply for all people at all times. • In _______, the government classified _______ Americans as “food insecure”. • ____________: a shortage of nutrients the body needs, as a result of poor quantity and quality of food.

46. Section 4 • _______________: occurs when a person does not get enough protein. • ________________: a condition that causes wasting of the muscles and other physical and mental problems.

47. Section 4 • Genetically modified organisms • _________________: any process in which scientists directly manipulate and organism’s DNA • ____________________: organisms that have undergone genetic engineering. • Produced by a process called __________________.

48. Section 4 • ______________________: the use of genetic engineering to introduce new genes into organisms to produce more valuable products. • The US grows about _______ of the total global GM crops. • Risks: • Benefits:

49. Section 4 • Industrial Food Production • _______________: • Advantages: • Disadvantages: • ____________________: • __________________: • Losses: • Preservation:

50. Section 4 • __________________: agriculture that does not deplete soil faster than it forms. • _________________: food-growing practices that use no synthetic fertilizers, insecticides, fungicides, or herbicides, but rely on biological approaches.