Environmental Science Chapter 12 Soil and Agricultre Environmental Science Chapter 12

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??

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.

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

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

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

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

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.

Section 1 ________________: breaking down rocks by chemical processes.

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.

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

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.

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

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

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

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 ______________.

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.

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

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.

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.

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……

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

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 ________________________.

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 ____________ ______________

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.

Section 2 Ranching Practices _________________: 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 _____________.

Section 2 Desertification 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.

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 ______%

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 _______ _____.

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.

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

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:

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.

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

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.

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.

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

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:

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

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

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.

Section 3 Pollinator populations have ______________. Ex: _______________

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

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.

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.

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.

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 __________________.

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:

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

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.

Section 4 ______________________: supporting local, small-scale agriculture.