Soil and Agricultre

Soil and AgricultreEnvironmental ScienceChapter 12THE central CasePossible Toxic Maize in Oaxaca, Mexico

How can we balance our growing demand for food with our need to protect the environment??Section 1Objectives

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 1What percent of the Earths 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 1Section 1Soil 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 Earths crustSection 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 RSoils differ from location to location, and few soils have all 6 horizons.Figure 4

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

Section 1Soil Characteristics____________, ______________, _____________, _________

_____________Dark soil:Pale soil: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

Section 1Sand particles do not stick to each otherClay particles do stick to each otherMost soils are a combination of clay, silt, and sand. When there is a relatively even mixture of the three the soil is called ______________.Section 1The 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 1StructureDescribes the arrangement of the soil particles

pHCan be either ____________ or ______________.

Section 2Objectives1. 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 2Studies 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 2The deterioration of the soil characteristics needed for plant growth or other ecosystem services is called ___________ ________________.

This can be devastating to ecosystems.

Lets look at how this can occurSection 2ErosionCan be a problem because it usually occurs ____________ than the rate at which soil is formed.Erosion can also ____________ soilsEx:

Section 2Today, human activity cause more erosion than do natural events.More than ___________acres of the worlds croplands now suffer from erosion and other forms of soil degradation.Reasons: _______________________, ______________________, and ________________________.Section 2In 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_________________: 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 2Forestry practices_____________ ____________ can lead to severe erosion._____________ __________: lead to less erosionDesertificationThe loss of more than 10% of productivity due to erosion, soil compaction, forest removal, overgrazing, drought, salt buildup, climate change, depletion of water. Section 2Some scientists suggest _______ of Earths land area is affected by desertification.

THE DUST BOWLIn the late 1800s and early 1900s settlers in OK, TX, KS, NM, and CO began tilling up the grasslands. Between _______ and ______ the farmed area of the Great Plains increases ______%Section 2Soil Conservation PoliciesIn 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 2U.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 2International Policies:________ ______ ____________ (FAO)____ _____ ____ ____ (FARM)Section 2Soil Pollution _________________: providing water to crops other than precipitation________________: the build up of salts in upper soil horizons.Can be made worse through irrigationHow?Solutions:Section 2PesticidesResidual chemicals could remain in the soil for long periods of time and may be toxic to humans.Chemicals can get into the groundwater contaminating itWe 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 3Objectives1. Discuss the beginnings of agriculture2. Explain the importance of industrial agriculture and the green revolution3. Identify different types of pest control4. Explain the importance of pollinators to agriculture

Section 3Agriculture 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 themFigure 16Section 3Biological 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 controlSection 3Pollinators:_______________: 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 3Pollinator populations have ______________.Ex: _______________Ex: _______________

Section 4Objectives1. Explain why the world needs to grow more food and grow it sustainably.2. Discuss genetically modified food3. Describe the advantages and disadvantages of industrial food production.4. Discuss sustainable agriculture

Section 4Each 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 4Genetically modified organisms _________________: any process in which scientists directly manipulate and organisms 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 4Industrial 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.