Chapter 9 Soil and Agriculture Guided Notes

Transcription

1 Chapter 9 Soil and Agriculture Guided Notes This lecture will help you understand: The relationship between and Major agricultural The fundamentals Causes and of soil erosion and Principles of soil No-till agriculture in Southern Brazil Southern Brazil s climate and make for Repeated has diminished the Leaving on their fields after harvesting and planting reduced, increased and cut These techniques have benefited Soil: the foundation for agriculture Land devoted to covers of surface = practice of raising and for human use and consumption = land used to for or = land used for livestock Soil = a complex plant-supporting system consisting of, organic, water, gases,, and microorganism o It is a Population and consumption degrades soil Feeding the world s requires changing our diet or increasing Land suitable for is We must find ways to the of food agriculture turns grasslands into ; removes ; diminishes ; and soil, air, and water o is blown and washed away Millions of acres of cropland are lost each year We lose ha (12-17 million acres) of productive cropland annually Soil degradation has many causes Soil degradation results from, agriculture and Over the past 50 years, has reduced production by Agriculture arose 10,000 years ago was invented by different The earliest plant and animal is from the of the o Wheat,, rye, peas, lentils,, goats,

2 Traditional agriculture Traditional agriculture =, using human and animal muscle power o = families produce only enough food for o = produces excess o Uses animals, irrigation and fertilizer, but not Industrialized agriculture is a recent phenomenon Industrialized agriculture = using and to boost yields o Also uses, and fertilizers o = uniform planting of a = the use of, and farming practices introduced to o Increased o Created and worsened Soil as a system Soil consists of, organic, air, and water o and microorganisms, and o, algae, earthworms,, mammals, amphibians, and Soil formation is slow and complex = the base of soil o Lava,,, dunes o = the continuous mass of solid rock comprising the Earth s crust Weathering = the,, or biological processes that break down rocks to form soil o (mechanical) =, no chemical changes in the parent material o = substances chemically interact with o = parent material Other processes affect soil formation = the dislodging and of o Occurs when Biological activity includes, decomposition, and of o = a, spongy, crumbly mass of material formed by partial A soil profile consists of horizons = each layer of soil = the of soil as a whole Up to horizons may occur in a soil profile o = inorganic and organic material most for plants o = dissolved particles through Soils are characterized in many ways Soils are classified based on,,, and = indicates its composition and

3 o or dark brown = rich in o gray or white = indicates = determined by the o From smallest to largest = o = soil with an even of the three o Influences how easy it is to and let travel through the soil Soil texture classification soils with, or loamy soils with mixtures of pore sizes are best for and Soil structure and ph Soil structure = a measure of soil s o Large clumps can o Repeated, decreasing its water-absorbing capabilities o = a hard layer resulting from repeated plowing that resists and root penetration Soil ph = influences a soil s ability to o Soils that are too can Cation exchange is vital for plant growth Cation exchange = process that allows o hold cations ( ions) of calcium, magnesium, and Cation exchange = a soil s ability to, preventing them from, thereby increasing their o A useful measure of o Greatest in Regional differences in soils affect agriculture have, but the nutrients are in plants, o Rain leaches minerals and, reducing their o = cultivation of a plot for a few years and then letting it have lower rainfall and Erosion degrades ecosystems and agriculture = the arrival of at its new location Flowing water in river valleys and deltas o are excellent for But, erosion is a problem because it occurs Erosion increases through:,, and clearing Soil erodes by several methods protect o Removing plants

4 erosion moves the most, followed by sheet and splash forms of erosion Water erosion occurs most easily on Erosion in the U.S. declined between o Soil conservation measures Various types of soil erosion A. B. C. D. Soil erosion is a global problem are the of erosion o It is occurring at In, erosion over the next 40 years could o Coupled with, some observers describe the future of agriculture as a Desertification Desertification = a loss of o Erosion,, forest removal, overgrazing,, climate change, Most prone areas = Desertification has high costs Desertification affects o In over Costs tens of billions of dollars each year o loses over alone from In Kenya, of the land is to desertification from The Dust Bowl In the late and early centuries, settlers arrived in, Texas, Kansas, and Colorado, grazed cattle o Removed A made conditions worse Thousands of and had to rely on The Soil Conservation Service Started in, the Service works with farmers to for farms o the land o Prepare an o Work closely with o Implement conservation measures = districts operate with federal direction,, and, but are organized by the states

5 Conservation districts Districts implement soil conservation programs to to plan and = 1994 renaming of the Soil Conservation Service o Expanded responsibilities include and pollution control o for efforts around the world Protecting soil: crop rotation and contour farming = the from to the next, o protect soil when main crops aren t planted o Wheat or corn and = plowing furrows sideways across a hillside, perpendicular to its slope, to Protecting soil: terracing and intercropping = level are cut into, sometimes with raised edges o A to contain = planting or other spatially mixed arrangements o Increases Protecting soil: shelterbelts and reduced tillage Shelterbelts or = rows of or other that are planted along the edges of fields to slow the o = shelterbelts + intercropping = furrows are cut in the soil, a is dropped in and the o No-till farming Pros and cons of no-till farming Almost uses Benefits:, greater crop yields, Negatives: increased use of and But, (dead plants and fertilizer) and minimizes the Plant cover reduces erosion Eroding and roadsides are stabilized by to China has the o It does o But it does not create, because are planted Irrigation: boosted productivity, but problems, too Irrigation = to support agriculture o become = over-irrigated soils

6 o Water = the buildup of in surface soil layers o Worse in Salinization prevention It is easier and salinization than Do not plant in sensitive areas Irrigate with, supplying only water that the crop requires o targets water Fertilizers boost yields but cause problems = substances that contain fertilizers = mined or mineral supplements fertilizers = the remains or o, crop residues o = produced when break down organic matter Overapplication of Fertilizer Inorganic fertilizer use has can ruin the soil and several areas causes in nearby water systems leach through soil and Nitrates can also (evaporate) into the Overgrazing causes soil degradation = too many of the plant cover o Impedes A leading cause of provide few to protect rangeland of the world s rangeland is classified as Effects of overgrazing can be striking Non-native invade o Less palatable to o Out compete Forestry impacts soil Along with and, impacts soils = the removal of from an area at o Leads to, especially on remove over longer periods of o Minimizes soil erosion U.S. programs promote soil conservation : Farmers that adopt plan receive and other Conservation Reserve Program (1985) o Farmers are paid to place highly into conservation reserves o are planted instead of crops o Saves 771 million tons of per year o Generates o Provides habitat for

7 Federal Agricultural Improvement Act (1996) Known as the o Aimed to reduce subsidies and over farm products o Created the and o Promotes and pays for conservation practices in (1998) o Provides for sustainable agricultural practices for International soil conservation programs (FAO) = the main agricultural program The FAO s Farmer-Centered Agricultural Resource Management Program (FAR) o Helps farmers success stories o Uses to and encourage farmers to and secure the food supply o Supports innovative approaches to and in around the world o China, Vietnam,, Sri Lanka,