Post on 22-Dec-2015
transcript
AGRICULTURE transforming natural ecosystem into one
devoted to production of food, fibre, & fuel
Requirements: huge amounts of land, water, energy genetic modification of plants and animals manipulation of resources and species
interactions
Advancements become more
productive world food production
kept up with rapid population growth
main livelihood of 40% of earth’s pop’n
provides both food and jobs/income
Environmental Costs reduced biodiversity destroyed natural ecosystems polluted/reduced freshwater ecosystems energy consumption greenhouse gas production major climate change contributor
Earth’s Land Resources ~ 37% Earth’s land used for agriculture 1/3 of this used for crops rest used for pastureland
not all land equally productive less productive areas require more
technology and inputs (eg fertilizer etc.) agriculture competing for space with
housing/businesses in developed countries land being deforested for agriculture in
developing countries
Agriculture
Productivity How much food/plants can be grown on a
certain area of land (hectare/acre)Differs widely depending on: soil water nutrients climate crop varieties energy
Soil CompositionMixture of: organic material from decaying plants and
dead organisms minerals from weathering and erosion of
rocks all soil different depending on type of rock,
plants, and climate of the area
Soil Profile5 Soil Layers (Horizons)
1. O Horizon (Litter) decaying organic matter releases
nutrients into soil usually darkest layer
2. A Horizon (Topsoil) 20-30 cm thick provides plants with nutrients rich in humus (decomposing plant
material) allows air and water to move
through soil
3. B Horizon (Subsoil) mix of rocks and humus roots can get some water from
groundwater4. C Horizon combination of weathered rock
and soil5. Bedrock – layer of solid rock under
soil
2c_soil_formation
Classifying Soils1. Texture: based on size of the particlesClay – many small, tightly packed particles,
little room for air, water or rootsSand – many large particles, lots of aeration,
too much water drains throughLoam – equal mixtures of sand and clay,
ideal since holds both air and waterYouTube - Soil Texture - Environmental Science
stored in soil for plant growth helps diffusion of gases, conduction of heat, and
the movement of nutrients moisture can be improved by improving the
aeration (air in soil)
3. Aeration plants (and microbes) require air to live compacted soil kills microbes and
decomposition of organic material slows fewer nutrients for plants toxins build up in soil and plants
2. Water
Non-mineral requirements: carbon, hydrogen & oxygenMacronutrients: nitrogen, phosphorous, potassium, calcium, magnesium, &
sulphur Fertilizers: can control nutrients usually contains 3 numbers referring to
the proportion of N, P, & K Ex Bone Meal – 4,12,0 nitrogen promotes lush green growth phosphorous promotes the growth of many flowers potassium promotes root growth (adds hardiness)
4. Required Nutrients
5. Acidity pH indicates the acidity or alkalinity of soil pH under 7 = acidic pH over 7 = alkaline (basic) most crops require soil between 6-7 pH acidity can occur naturally also because of use of nitrogen fertilizers,
manure, and acid precipitation acidic soil can be treated with lime or calcium to
reduce acidity alkaline treated by adding sulphur
Regi’s Gardens1.Russell St DoorsREGIS\Regis 5 of 5 P.pdfConditions: north facing moist/damp
Plants: Sedge grass – shady areas Royal fern – damp & shade Hostas – shady areasREGIS\Regis Photo Raised Grdn.jpg
2. Beside Stairs to FieldREGIS\Regis 4 of 5 P.pdfConditions: north facing under trees weedyPlants: sedge grass hostas bugle carpet – ground cover, partial shadeREGIS\Regis Stairs.jpg
3. Next to Sports FieldREGIS\Regis 3 of 5 P.pdfREGIS\Regis 2 of 5 L.pdfConditions: west facing full sun next to concrete wall and pavement - hotPlants: blue oat grass – hot weather, drought tolerant sedums –drought tolerant, grown in poor soils spurges – dry poor soil spiderworts – full sun, dry conditions