Human Impacts on Human Impacts on Ecosystems: Agricultural UseEcosystems: Agricultural Use

SVN3ESVN3E

HistoryHistory

Historically, the largest demand Historically, the largest demand humans have placed on ecosystems humans have placed on ecosystems has been agricultural use of land.has been agricultural use of land.

(i.e. farming)(i.e. farming)

Sustainable AgricultureSustainable Agriculture

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

Nutrient DepletionNutrient Depletion

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

ErosionErosion

Sustainable Sustainable agriculture also agriculture also prevents prevents erosionerosion of of the topsoil.the topsoil.

erosion: the process erosion: the process by which the by which the surface of the earth surface of the earth is worn away is worn away

TillageTillage

Historically, Historically, tillingtilling the earth could the earth could result in erosion.result in erosion.

tillage: preparing soil for planting by tillage: preparing soil for planting by mechanical agitationmechanical agitation

Preventing ErosionPreventing Erosion

Sustainable farming uses:Sustainable farming uses: No-till farmingNo-till farming Natural windbreaks (trees)Natural windbreaks (trees) Planting at 90Planting at 90oo to the slope to the slope

IrrigationIrrigation

Soil erosion can be accelerated by Soil erosion can be accelerated by precipitation or precipitation or irrigationirrigation, the , the artificial application of water to the artificial application of water to the soil.soil.

Flood irrigation

SalinizationSalinization

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

OveruseOveruse

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

Sustainable IrrigationSustainable Irrigation

Sustainable irrigation Sustainable irrigation solutions include:solutions include:

Rainwater harvestingRainwater harvesting Drip irrigationDrip irrigation Drought-resistant crops Drought-resistant crops

and soilsand soils

Carbon FootprintCarbon Footprint

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

Local AgricultureLocal Agriculture

Local food production allows consumers Local food production allows consumers to ensure that producers are using to ensure that producers are using sustainable agriculture sustainable agriculture andand reduces reduces transportation costs.transportation costs.

locavorelocavore: someone who consumes : someone who consumes locally-grown foodlocally-grown food

Fresh vs. ProcessedFresh vs. Processed

Local food can also be fresher: Local food can also be fresher:

it is picked ripe instead of green and it is picked ripe instead of green and requires less preservation requires less preservation (refrigeration and processing).(refrigeration and processing).

The Future?The Future?

Our carbon-stressed future might Our carbon-stressed future might contain more local agriculture:contain more local agriculture:

Backyard and Rooftop gardensBackyard and Rooftop gardens Vertical farmsVertical farms