Chapter+14+Agriculture

**__ The Development of Agriculture __** __ History __ 1. ** Early ancestors ** -obtained food by **hunting and gathering.**
 * //__ Chapter 14: Agricultural Methods and __//****//__ Pest __//****//__ Management __//**

2. Then, new “ innovation”=**slash and burn agriculture.** 10,000 years ago – 5 million people on the planet. Today – over 6 billion… a. Burning trees/slash returns nutrients to soil, within 2-3 years, site is abandoned for better soils. b. Used where soil layer is thin and nutrient poor (tropics and on slopes). c. Human pop requires faster turnover time and gardens are larger. **Succession** halted. d. Gardens typically have mixture of plant types= **polyculture.**

3. ** Labor –intensive agriculture ** (till, plant, harvest) = areas with better soils – practiced in much of the world today because: a. Mechanization not possible b. Kind of crop does not allow for mechanization – some crops require more weeding and handling than others ( rice paddies, stages of cotton, fruits and delicate veggies) c. ** Economics ** prevent people from purchasing tools and machines. In many countries, cost of human labor is low. Primary reason for use. d. Labor-intensive agriculture most common – 70% of China and India -2 billion people in these countries eat this way.

4. ** Mechanized agriculture – ** Industrial Revolution (horse drawn farm implements and tractors  ** a. ** Requires vast expanses of flat land   ** b. ** Fossil fuels vs muscle power   ** c. ** Land planted with same crop or must constantly change farm machinery and tools,and workers would have to miss areas of land planted with different crops not ready for harvest. Wastes time, fuel, money. Inefficient. **Monoculture resulted**

** d. ** Monoculture greatly increased the amount of food produced per hectare in last 100 years. Did not solve world hunger problem (pop increasing faster rate) ** e. **** Green Revolution ** 1950s,60,70 ** “Pro” ** worldwide introduction of new plant varieties and farming methods ( food production increased significantly in third world countries) ** “Con” ** modern farming (new crop types) requires fertilizers, pesticides, higher amounts of water – irrigation-use of fossil fuels **__ Impact of Fertilizer __** 25% of world’s crop yield due to fertilizer use. Increasing every year. 1. Made from oil products, so price changes when oil prices change. Needed because removal of harvested crops, removes nutrients in tissues. 2. Replaces **macronutrients** – solid nitrogen, phosphorus, potassium cpds 3. Replaces **micronutrients**- boron, zinc, manganese. Ex: 1 ton of potatoes removes 22lbs of nitrogen, 0.03 lbs of boron. 4. Fertilizer **DOES NOT REPLACE HUMUS** – soil organic matter.

**__ Agricultural Chemical Use in U.S. $26 billion alone __** Mechanized monoculture also requires Pesticides (pest – life form human wants to get rid of). Pesticides kill target and sometimes nontarget organisms. “Biocides??” Older pesticides: persistent Newer pesticides: nonpersistent if possible

1. Insecticides 2. Fungicides <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 81pt; text-indent: -0.25in;">3. Rodenticides

** 1. **** Insecticides- ** · Chlorinated hydrocarbons (persistent) DDT · Organophosphates and Carbamates (nervous system damage – acetylcholine blocker) *Malathion ( mosquitoes), parathion (toxic) diazinon (Sevin-household) ** 2. **** Herbicides- ** · 60% of pesticides used are herbicides “weed killers” · Mixtures work best, stop weeds at various stages of growth – selective for monocots or dicots for example. Diuron-kills all plants at high doses Fenuron-kills woody plants (along power lines and road ways) Atrazine-kills dicots in corn, sugar cane, pineapple fields, Christmas trees Glyphosate-clears cropland, broad-spectrum

** 3. **** Fungicides – fungus; ** help create soils, pests on crops Fungicides are fumignats, sprays and dusts – methylmercury on seeds – bright orange for safety, not for human consumption

4. ** Rodenticide- rodents: ** destroy food crops, but also carry disease causing agents ** Bounties/traps ** paid in third world countries **Warfarin** – rodents eat it in food, prevents clotting, causes hemorrhaging. **Rodent – proof buildings**

** 5. **** Other agricultural chemicals ** ** Auxins- ** plant hormone that disrupts normal plant growth (spray on cotton so leaves fall off, easier to harvest cotton) ** NAA ** (__n__aphthalene__a__cetic __a__cid) prevents fruits from dropping from trees – 10 estra days for harvesting

** Ethephon ** loosens fruit so falls off tree easily

**__ Traits of the Perfect Pesticide __** <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">1. Inexpensive <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">2. Only affects target organism – high kill rate, lowers chances of inherited resistance. Does not wipe enough competitors that more difficult – to manage – pests move in ( cotton bollworm + tobacco worm both filled the new niches) <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 0pt 0.5in; text-indent: -0.25in;">3. Nonpersistent-prevent bioaccumulation (individual) and biomaginifcation( through food chain) DDT, aldrin, dieldrin, heptachlor, chlordane – termites until 1987 <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.5in; text-indent: -0.25in;">4. Breaks down into harmless materials **__ Human Health Concerns __** ** Short term- ** WHO estimates 1-5 million acute pesticide poisonings, 20.00 deaths/year (farmers in 3rd world countries) ** Long-term- ** Most critical health problem – inadvertent exposure over the long – term · Mutations · Cancers · Abnormal births · Miscarriages Why concerns in 3rd world countries? <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1.25in; tabstops: list 1.25in; tabstops: list 1.25in; text-indent: -0.25in;">1. Low literacy <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1.25in; tabstops: list 1.25in; tabstops: list 1.25in; text-indent: -0.25in;">2. Weak/absent regulatory legislation <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1.25in; tabstops: list 1.25in; tabstops: list 1.25in; text-indent: -0.25in;">3. Climate factors – no protection worn, too hot <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1.25in; tabstops: list 1.25in; tabstops: list 1.25in; text-indent: -0.25in;">4. Faulty spraying methods <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 1.25in; tabstops: list 1.25in; tabstops: list 1.25in; text-indent: -0.25in;">5. Unhealthy population, not resistant **__ So, why use pesticides? __** <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.25in;">$18 billion loss annually for US alone. **__ Alternatives to Conventional Agriculture __** <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.25in;">Guided by general principles · Keep insecticides, herbicides, fungicides, fertilizers to a minimum · Biological diversity used in same areas · Protect/support the soils · Use beneficial insects to combat pest insects <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.25in;">Organically grown crops (30 definitions in 50 states) Cost!! <span style="display: block; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; text-align: center;">Handlers certified, farms increase soil fertility, prohibit use of synthetic pesticides and fertilizers
 * 1) <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; tabstops: list .5in; tabstops: list .5in;">In US alone, 33% of crops destroyed by pests – worldwide-35%
 * 1) <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; tabstops: list .5in; tabstops: list .5in;">Cost of pesticides more than offsets increased yields and profits for farmers.
 * 2) <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; tabstops: list .5in; tabstops: list .5in;">Many health problems impossible to control without pesticides – big demand
 * 1) ** Alternative agriculture **
 * 1) ** Sustainable agriculture **
 * ** Precision agriculture ** - computers models now tell us topography, soil make up – water content- so that fertilizers and pesticides are better managed and more effective. Crop rotation can be better planned and timed.

<span style="display: block; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; text-align: center;">Must understand ALL phases of life cycle and metabolism of the crops grown, and chemistry for rotation sequences. Studies are expensive. ** Disrupt Reproduction ** ** Pheromones ** used – chemicals that females release to attract males used to consolidate insect groups. ** Sterilize males – ** screwworm epidemics ended in Venezuela, Mexico, Libya, and Central America in 1990. Mediterranean fruitfly epidemic in Cal halted this way, too. X rays used to sterilize. **__ Beneficial Organisms Fight Pests __** ** 1. Intentional predator-prey relationships ** <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.25in;">Ex: ladybird beetle, ladybug, natural predator of aphids and scales. Must be sure introduced predator doesn’t upset other pieces of ecosystem – difficult to access. ** 2. Herbivorous insects: ** purple loosestrife – wetlands ( not a problem in Canada as insect species naturally control.  __ Water Connections (Envirothon 2011) __  Summer dead zones in oceans ( ex Gulf of Mexico)- few fish and bottom – dwelling organisms ( hypoxia – low oxygen) due to increased algal blooms and bacterial decomp of dying over-populated algae as “ BOD” too high.
 * ** Integrated pest management ** -variety of methods used to control pests

Hypoxia begins when fertilizers with nitrogen wash downstream and accumulate in the estuaries of ocean, then beyond. Differences in salinity and temp cause layering. Over feewding of bottom of fodd chain causes massive cell reproduction, and death. Oxygen pulled from water by bacteria cause final death due to suffocation. Crustaceans suffocate – cold saltwater sinks, warmer water rises above. Stuck in toxic situations.

Nutrient pollution degraded half of US estuaries. Most important problem facing US coastal waters – sustainability of fisheries.

How reduce hypoxia induced by nitrogen release: <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.5in; text-indent: -0.25in;">1. Reduce use of nitrogen-based fertilizers and improve storage of manure. <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.5in; text-indent: -0.25in;">2. Reduce runoff from feedlots. <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.5in; text-indent: -0.25in;">3. Plant perennial crops instead of fertilizer – intensive corn and soybeans on 10 percent of the acreage. <span style="font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.5in; text-indent: -0.25in;">4. Restore 2 million – 4 million hectares (5-10 million acres) of wetlands, which absorb nutrient runoff.

Several species of beetles used at different life phases of loosestrife – launches multi-pronged attack on purple loosestrife. Larvae destruction, then feed on leaves, stems, flowers, etc.

Bacterium __Bacillus thuringiensis__ used to control mosquitoes and moths another example of biological warfare. Destroys gut lining.

Marigolds reduce soil nematodes and garlic plants keep Japanese beetles in check. __ Design Resistant Crops __ Outcome of MoBi research - development of specialized organisms that have specific, valuable genes inserted into their genetic make up.

Manipulate DNA of organisms – genetic engineering, biotechnology = create GMOs. 60% of foods in US supermarkets derived from GMO crops. 2/3 of GM crfops in US. Argentina, Brazil, also high. Canada - canola oil. 1983- tobacco first GM crop 1993- Flavr-savr tomato Golden rice – Vitamin A increased, blindness incidences dropping drastically! 1. __ Genes that destroy predators __ Several crop plants now make the __Bacillus thuriniengsis__ toxin that destroys the gut of insect pests. Concern is pollen travelling to nearby fields – especially if organic farm nearby. 2. __ Genes that make plant herbicide resistant- __ spray whole field of crop, only target herbs destroyed. Concern is gene will jump species and we will create super-resistant weeds (a problem already)

Pro – supporters argue we have selectively bred plants for centuries. Produces more food economically – high yield seeds. Enhance nutritional quality. Increase shelf-life. Decrease allergenic contents. Put vaccines into crops. Convert toxic or arid soils into land productive for agriculture.

Con – technology has no long-term studies to identify unanticipated danger of modifying genes to order. The European Union will not buy genetically modified grains from the United States. Genes to travel between species naturally.

__ Modify Farming Practices __ <span style="color: black; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.75in; text-indent: -0.25in;">1. Crop rotation on same field <span style="color: black; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.75in; text-indent: -0.25in;">2. Destroy crop residues at end of each harvest so that remaining insect pests are destroyed before next planting begins. No carry over or overwintering. <span style="color: black; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.75in; text-indent: -0.25in;">3. Use trained professionals to selectively and effectively manage pesticide use. Farmers could become licensed to apply chemicals. <span style="color: black; font-family: 'Comic Sans MS'; font-size: 12pt; line-height: 115%; margin: 0in 0in 10pt 0.75in; text-indent: -0.25in;">4. Integrated pest management key.