1 Agricultural Methods and their effect on biodiversity and the environment

Learning Goals: Understand how and why agriculture practices have changed over the years, and the effect this has had on the environment and biodiversity 2

3 Development of Agriculture Development of agriculture involved manipulating the natural environment to produce food desired by humans. – PAST: People would move seeds closer to home or shake seed heads to increase seed production following year.  Labor intensive  Hand picked insect pests  Hand harvested – PRESENT: 75 years ago – move from hand or animal labor to machines  Dramatically increased size of crops, mass production, and loss of biodiversity due to monoculture crops  Chemical use also recent (since 1950’s)

4 Increased Agricultural Yields

5 Mechanized Agriculture – Typical of industrialized countries. – Fossil fuel replaces human muscle power – Need large amounts of energy and flat land. – Often use monocultures (only one type of plant for each crop) because of more efficient planting, cultivating and harvesting.

6 MONOCULTURE vs POLYCULTURE Definition: using multiple crops in the same space, in imitation of the diversity of natural ecosystems Definition: growing only one species in a crops in the same space

7 Problems with Monocultures Little genetic diversity can be detrimental if a new pest attacks the crop because entire crop is lost - leading to increased pesticide use No crop rotation depletes soil nutrients thus increasing fertilizer use

8 Modern Technologically Advanced Agriculture – 1913: Required average of 135 hours of labor to produce 2,500 kg of corn – 1980: Required average of 15 hours PRO: increases production rate, more food=more money CONS: Drastically increases pollution made in harvesting, planting, pesticide and fertilizer manufacturing thus reducing biodiversity

9 Solutions Modifying Farming Practices – Crop Rotation (Plant a species like alfalfa that naturally brings Nitrogen back into the soil) – Use Polycultures Selective Use of Pesticides – Identification of precise time when pesticide application will have the greatest effect at the lowest possible dose.

Biodiversity When we grow monocultures and not polycultures, which 2 types of biodiversity are affected? Think/Pair/Share 10

Learning Goals: Do we: Understand how and why agriculture practices have changed over the years, and the effect this has had on the environment and biodiversity? 11