Chapter 15 Agriculture and Pest Management Agriculture Methods

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Chapter 15 Agriculture and Pest Management Agriculture Methods • Slash and Burn Agriculture. –

Chapter 15 Agriculture and Pest Management Agriculture Methods • Slash and Burn Agriculture. – – Small areas - usually in tropics Burning returns nutrients to soil polyculture practiced = plant many different types of plants Land recovers - forest re-invades • Labor Intensive Agriculture • Occurs under three conditions – 1. When topography won’t allow mechanization – 2. When crop won’t allow it – 3. Where cost is prohibitive and labor cheap

Chapter 15 Mechanized Agriculture • Typical of North America, Europe and former Soviet Union

Chapter 15 Mechanized Agriculture • Typical of North America, Europe and former Soviet Union • Requires large tracts of land • Special varieties of plants that can be harvested by mechanical means (hybrids, G. E. species) • monoculture = planting only one species of plants on large areas • Can cause soil erosion and depletion of soil nutrients • Cheap fuel - energy from fossil fuels replaces labor • Has significantly increased food production

Chapter 15 Energy Versus Labor • Mechanized agriculture substitutes energy from petroleum for human

Chapter 15 Energy Versus Labor • Mechanized agriculture substitutes energy from petroleum for human labor – 1913 - took 135 hours of labor to produce 2, 500 kilograms of corn – 1980 - took 15 hours to produce 3500 kilograms of corn • Energy from petroleum is used for: – Tilling, planting harvesting, pumping water, – To produce fertilizers, pesticides - herbicides, fungicides and insecticides – Changes in the cost or availability of fuel will impact on the worlds ability to feed itself!!!! • Broad implication of US dependence on foreign oil

Chapter 15 Impacts of fertilizers • 25% of the world’s crop yields is attributed

Chapter 15 Impacts of fertilizers • 25% of the world’s crop yields is attributed to the use of fertilizers - no fertilizers- 25% decrease in food • oil costs - poverty- hunger - fertilizer paradox • Macro nutrients – nitrogen (N), phosphorus (P), potassium(K)– also C, H, O but… • Micronutrient – copper zinc, iron, magnesium, manganese, boron, etc • Why do we have to fertilize? Where do the Macro nutrients and micronutrients go?

Chapter 15 Inorganic fertilizers do not replace organic matter ! • Why is organic

Chapter 15 Inorganic fertilizers do not replace organic matter ! • Why is organic matter important? • Humus – – – prevents compaction, makes poor spaces lowers p. H serves as food for bacteria and earthworms holds moisture holds nutrients and provides slow release of them, less runoff of pollutants • Total dependency on inorganic fertilizers causes adverse changes in soil properties.

Chapter 15 Pesticides • Pesticide = any chemical used to kill or control the

Chapter 15 Pesticides • Pesticide = any chemical used to kill or control the populations of unwanted fungi, animals, or plants (pests). Weeds = unwanted plants – – Herbicide = kills plants Insecticide = kills insects fungicide = kills fungi rodenticide = kills mice and rats • Target organisms = pests you desire to kill • nontarget organisms = other organisms killed by a pesticide in addition to targeted pest including many beneficial organisms

Chapter 15 Insecticides • Natural insecticides – Nicotine – Pyrethrum - chrysanthemums – Rotenone

Chapter 15 Insecticides • Natural insecticides – Nicotine – Pyrethrum - chrysanthemums – Rotenone • • Synthetic organic insecticides 1867 - Paris green - acetate and arsenide 1942 - DDT - dichlorodiphenyltrichloroethne DDT saved 5 million lives in first ten years of uses. BUT insects became tolerant and DDT biomagnified !!!!

Chapter 15 Three Types of Synthetic Insecticides • 1. Chlorinated hydrocarbons – Examples: DDT,

Chapter 15 Three Types of Synthetic Insecticides • 1. Chlorinated hydrocarbons – Examples: DDT, aldrin, dieldrin, toxaphene, chlordane, mirex, kepone • Mode of action – thought to be a neurotoxin, but mode(s) of action is / are not fully understood • Very persistent- half life 10 -15 years • Banned in U. S. but still used in developing countries—problem?

Chapter 15 2. Organophosphate – Examples: Chlorpyrifos (Dursban) Diazinon (Spectracide), Malathion • Mode of

Chapter 15 2. Organophosphate – Examples: Chlorpyrifos (Dursban) Diazinon (Spectracide), Malathion • Mode of action - cholinesterase inhibitor • Short half lives, but more toxic to humans and require more frequent applications 3. Carbamates – Examples: carbaryl (Sevin) • Mode of action - cholinesterase poison • Half life - short - hours/days

Chapter 15 Problems With Pesticide Use • 1. Persistence - hard pesticides – Global

Chapter 15 Problems With Pesticide Use • 1. Persistence - hard pesticides – Global transport - found all over the world – Bioconcentration, bioaccumulation, biomagnification (amplification) • 2. Insects build up resistance • 3. Impacts on non-target beneficial organisms • 4. Short term and long term health problems of farm workers

Chapter 15 Reasons Pesticides Are Widely Used • 1. Use of Pesticides has increased

Chapter 15 Reasons Pesticides Are Widely Used • 1. Use of Pesticides has increased about of food that can be grown worldwide • 2. Economics - cost of pesticides is less than the increased value of crops produced • 3. Needed to control disease organisms

Chapter 15 Organic Farming • Prior to availability of fertilizers and pesticides all farming

Chapter 15 Organic Farming • Prior to availability of fertilizers and pesticides all farming was organic • Organic farming is use of animal manure, crop rotation, mixture of crops, manual labor or biocontrol to kill pests • “Organically grown” vegetables, grains and meat are gaining in popularity because of health concerns over use of pesticides and because of nutrition concerns

Chapter 15 Integrated Pest Management • Integrated Pest Management = use of a variety

Chapter 15 Integrated Pest Management • Integrated Pest Management = use of a variety of methods to control pests rather relying on use of pesticides alone - Integrated use of chemical, physical and biological methods of controlling pests • Examples: Use of sex attractants (pheromones), male sterilization, release of predators and parasites, pest resistant crops, use of natural pesticides, modification of farming techniques