1. Human Impacts on Ecosystems: Agricultural Use SVN3E

2. History Historically, the largest demand humans have placed on ecosystems has been agricultural use of land. (i.e. farming) (i.e. farming)

3. Sustainable Agriculture Sustainable agriculture refers to the practice of farming using principles of ecology: using natural cycles rather than disrupting them.

4. Nutrient Depletion E.g. returning nutrients to the soil using the compost or manure that were part of the nutrient cycle.

5. Erosion Sustainable agriculture also prevents erosion of the topsoil. erosion: the process by which the surface of the earth is worn away

6. Tillage Historically, tilling the earth could result in erosion. tillage: preparing soil for planting by mechanical agitation

7. Preventing Erosion Sustainable farming uses: No-till farming No-till farming Natural windbreaks (trees) Natural windbreaks (trees) Planting at 90 o to the slope Planting at 90 o to the slope

8. Irrigation Soil erosion can be accelerated by precipitation or irrigation, the artificial application of water to the soil. Flood irrigation

9. Salinization Irrigation can also cause salinization, the build-up of salt deposits in the soil to levels harmful to crops.

10. Overuse Many areas also use groundwater for irrigation (e.g. the vast Ogallala High Plains aquifer) at greater rates than it is being replenished by rainfall.

11. Sustainable Irrigation Sustainable irrigation solutions include: Rainwater harvesting Rainwater harvesting Drip irrigation Drip irrigation Drought-resistant crops and soils Drought-resistant crops and soils

12. Carbon Footprint Sustainable agriculture also helps reduce our carbon footprint, the amount of carbon dioxide emitted because of fossil fuel use (in fertilizers, in transportation, etc.).

13. Local Agriculture Local food production allows consumers to ensure that producers are using sustainable agriculture and reduces transportation costs. locavore: someone who consumes locally-grown food

14. Fresh vs. Processed Local food can also be fresher: it is picked ripe instead of green and requires less preservation (refrigeration and processing).

15. The Future? Our carbon-stressed future might contain more local agriculture: Backyard and Rooftop gardens Backyard and Rooftop gardens Vertical farms Vertical farms