Crops and Soil SEV5: Students will recognize that human beings are part of the global ecosystem and will evaluate the effects of human activities and technology on ecosystems. Objectives Distinguish between traditional and modern agriculture techniques Describe fertile soil Describe why we need soil conservation Explain pros and cons of pesticide use Explain what is integrated pest management How is genetic engineering used Did you know. Did you know most of the Earths surface CANNOT be farmed? Only 10% of the surface is arable land (land that can be used to grow crops) Did you know We have converted 38% of Earths surface for agriculture, the practice of cultivating soil, producing crops, and raising livestock for human use and consumption. Croplands (for growing plant crops) and rangelands (for grazing animal livestock) depend on healthy soil. Agriculture: Sustaniable, Traditional and Modern Covers processes and main types of agriculture Agriculture: Traditional and Modern What are the basic processes of farming? Plowing Fertilization Irrigation Pest control What is plowing? Used to mix nutrients into soil, loosen soil and remove weeds Can be done manually by hand or animal or with a machine Plowing What is irrigation? Method to water crops Can be performed by a series of canals/ditches or sprinklers/drip systems What is pest control? Controlling of unwanted organisms that harm crops Can use biological pest controls or pesticides What is fertilization? Adding nutrients to the soil to enhance plant growth Can use organic fertilizers (like manure and compost) or chemicals 2 main types of agriculture: Traditional agriculture Traditional agriculture has been used since earliest days of farming Plows pushed manually by hand or animal Organic fertilizers are used Irrigation through ditches Weeds removed by hand or machine 2 main types of agriculture: Modern agriculture Used by industrialized countries; uses machines powered by fossil fuels Synthetic chemical are used for fertilizers and pesticides Drip system or sprinklers for irrigation Sustainable agriculture Sustainable agriculture is farming that conserves natural resources AND keeps the land productive Fertile soil: The living Earth Fertile soil, erosion, conservation, enriching and salinity What is soil composed of? Fertile soil can support the growth of healthy plants Plant roots grow in the topsoil (top layer), which is rich in nutrients. Top soil continued Fertile topsoil is composed of the following: Living organisms Rock particles Water Air Organic matter https://www.youtube.com/watch?v=VuHznslr8a I https://www.youtube.com/watch?v=VuHznslr8a I Layers of soil Surface litter/ organic later Top soil Subsoil: large rock particles Bedrock: solid rock layer Soil Erosion Erosion is the movement of rock and soil by wind and water In the United States about half of the original topsoil has been eroded in the last 200 years! Mot farming methods increase the rate of erosion The Dust Bowl Drought and degraded farmland produced the 1930s Dust Bowl. Storms brought dust from the U.S. Great Plains all the way to New York and Washington, and wrecked many lives. Erosion causes Commonly caused by: Over cultivating, too much plowing, poor planning Overgrazing rangeland with livestock Deforestation, especially on slopes Types of soil erosion What is land degradion? Land degradion occurs when the land is damaged and can no longer support the local ecosystem Desertification is the process in which land becomes arid (desert like) Swidden agriculture In swidden agriculture, tropical forest is cut, the plot is farmed for 1-2 years, and the farmer moves on to clear another plot, leaving the first to regrow into forest. Causes of soil degradation Most soil degradation is caused by: Livestock overgrazing Deforestation Cropland agriculture World soil conditions Soils are becoming degraded in many regions. Soil Conservation Soil conservation is the protection of soil from erosion and other types of deterioration, so as to maintain soil fertility and productivity. It generally includes watershed management and water use Preventing soil degradation Several farming strategies to prevent soil degradation: Crop rotation Contour farming Intercropping Terracing Shelterbelts Conservation tillage Crop rotation Crop Rotation : Alternating the crop planted Can restore nutrients to soil and fight pests and disease. Contour farming Contour farming : Planting along contour lines of slopes Helps reduce erosion on hillsides. Intercropping Intercropping : Mixing crops Can provide nutrients and reduce erosion. Terracing Terracing : Cutting stair steps or terraces Only way to farm extremely steep hillsides without causing massive erosion. Labor intensive Shelterbelts Shelterbelts : Rows of fast-growing trees around crop plantings Provide windbreaks, reducing erosion by wind. Conservation tillage Conservation tillage : No-till and reduced-tillage farming leaves old crop residue on the ground instead of plowing it into soil. This covers the soil, keeping it in place. Enriching the soil Soil can be enriched by manure, decaying leaves and compost. Compost is partially decayed organic material Salinization Salinization is the accumulation of salts in the soil Many plants can not tolerate high salt concentrations! Pest control Pesticides, biological pest control, pest management What is a pest? A pest is any organism that can cause damage or is not wanted Pesticides Pesticides are chemicals used to kill insects, weeds, and other pests Pesticides can also kill beneficial organisms Pesticide resistance Over time pests can become resistant to pesticides https://www.youtube.com/watch?v=r- 5R41tVIDY Health concerns Contact with pesticides can lead to Cancer Long term illnesses nervous system complications may irritate the skin or eyes May affects hormones https://www.youtube.com/watch?v=5ZhJYBn tPKE The environment Some pesticides do not break down over time This can lead to biomagnification in organisms Biological pest control Biological pest control is the use of living organisms to control pests Three main categories: Pathogens Plant defenses Chemicals from plants https://www.youtube.com/watch?v=MRn3g5jvu5I Genetic engendering What is genetic engineering? Genetic engineering is the modifying of DNA Why modify? Reasons for genetic engineering in farming Resist disease, pests and drought Larger yields Reduce spoilage How long have we been genetically modifying food? Food has been genetically enhanced for thousands of years Humans will choose which organisms breed to one another. This is called selective breeding. How is genetic modification performed? Genetic engineering is similar to cut and paste on the computer First you select a gene and cut it out Then the gene is transferred into the target organism and pasted into the genome. Once inserted, the organism can pass the new gene onto its offspring Feeding the world Activator Why is nutrition important? Organisms need food for energy and as building blocks The amount of energy that is in food is called calories Major nutrients needed Every organism need 3 essential nutrients (also called macromolecules) They are Carbohydrates Lipids Proteins Carbohydrates Sugars are the primary source of energy Lipids Fats are used for Insulation (blubber) Forms cell membranes and hormones Long term storage of energy Proteins Proteins are made up of amino acids. Together, these help to build muscles and body structures What happens when you do not get enough to eat? Malnutrition can occur in 2 ways Not enough calories Not enough variety in foods World problems About 1/3 rd of your calories are from animal products Currently farmers produce enough grains to feed 10 billion people a VEGETARIEAN diet World problems Most malnutrition today is a direct result of poverty Most of the worlds hungry are subsistence farmers (grow only enough for local use) Subsistence farmers Work tiny plot of land Sell leftover food in town Typically do not have enough water of irrigation Most make less than $1 a day Famine Famine is widespread starvation caused by a shortage of food Caused by war, lack of rain, and erosion of soil