apes unit 5 (land and water use)

agriculture (ecological services)

• help maintain water flow and infiltration

• provide partial erosion protection

• can build soil organic matter

• store atmospheric carbon

• provide wildlife habitat for some species

agriculture (economic services)

• food crops

• oil crops

• industrial crops

• fiber crops

• jobs

traditional agriculture

• interplanting (several crops on same plot over time)

• heavy human and animal labor

• polyvarietal cultivation (genetic varieties of the same crop)

• intercropping (two or more different crops grown at the same time)

• agroforestry or alley cropping (crops and trees grown together

• polyculture (different maturation dates)

green revolution (60s/70s)

• norma borlaug is considered the “father of the green revolution”

• nobel peace prize in 1970

• increased yields saved millions from starvation

• developed high-yielding varieties of cereal grains

• install irrigation infrastructure

• distribute hybridized seeds

• use data

• synthetic fertilizers and pesticides

cons of the green revolution

• taking away nutrients forces you to produce and add synthetic ones

• monocropping alerts insects and encourages use of more pesticides

high yielding plant monocultures

• reduced biodiversity

• became susceptible to catastrophic outcomes

• easy to plant, maintain, harvest

• only certain types of pests associated with this one crop

• loss of habitat and biodiversity

• loss of ancestral varieties

mechanization of planting and harvesting

• high efficiency

• increased the use of energy with corresponding negatives

• very high entry costs

• can be specialized and updated

• easy to use

• efficiency leads to higher profits

artificial fertilizers

• produced through the haber bosch process (N2 + 3H2 —> 2NH3)

• releases nutrient over time

• can be customized by type of plant

• mass produced

• easily shipped and stored

• easily and quickly dispersed

• no objectionable smell

• increased yields

• easily dissolve in run off, eutrophication

• nitrogen bearing ions in drinking water

• accelerates the nitrogen cycle

artificial pesticides, herbicides, fungicides

• increased yield

• can target organisms

• health impacts

• possible extermination of nontarget species

• contamination of groundwater

• evolution of pesticide resistant pests (pesticide treadmill)

industrialized agriculture

• large inputs of capital and energy

• fossil fuels, machinery, irrigation equipment

• commercial inorganic fertilizers and pesticides

• 10 units of energy needed to put on unit of energy on the table

soil erosion

caused by flowing water and wind (weathering breaks down rocks but doesn’t involve movement), enhanced by humans through farming and logging

irrigation

• customizable application

• maximizes yield by maximizing growth potential

• depletion of freshwater sources

• salinization, water contains dissolved salts, when the plants absorb it or the water evaporates it leaves the salt behind. the salt accumulates and builds up in the soil making it hard for salt intolerant plants to resist and dry as well as giving it poor drainage

genetically modified organisms

human directed evolution that selects for traits beneficial to humans based on the genetic material available

takes advantage of the genetic material of normally incompatible species, thus creating new traits in the host species

creates crops that can grow on land that was once unusable due to drought, heat resistance and salt tolerance

can be herbicide resistant (easy and early application of herbicide without crop damage)

crops can produce their own incesticide (reduces the use of artificial ones)

semiarid and arid lands converted to agriculture have low nutrient soil

weeds can become herbicide resistant with excess use

bt crops may kill nontarget species

bt crops can lead to insecticide resistant pests

moral/ethical/economic issues with patented genetic modification

tilling

• bare soil —> soil erosion, evaporation (eutrophication, need for fertilizer)

• turned soil —> impacts soil structure (this is bad because soil is a habitat and a home for microbes and worms also contains nutrients for plants)

• turned soil —> sequestered carbon released as CO2

slash and burn

• mostly used in developing countries

• typically in tropical rainforest (low nutrient soil due to high rates of decomposition and nutrient cycling)

• subsistence farmers

• ash used as fertilizer

• unsustainable because nutrients produced by ash are used quickly, cut down new plot of land for crops

• resulting impacts are desertification, forest cannot grow back, soil erosion, decreased albedo, increased evaporation, decreased water infiltration

flood irrigation

diverted lake/spring river by digging a trench to your area

• easy, inexpensive, mechanization not required, easily used in developing countries

• requires water plant nearby, not for all plant types, land must be graded, levees needed, 20% of water lost to evaporation, waterlogging/salinzation

furrow irrigation

build furrows/trenches on either side of crops, divert water

• low investment, high-sediment water can be used

• allows for some precision of application

• not efficient on sandy soil, difficult to apply small amounts, 33% of water lost to evaporation, soil erosion

spray irrigation

pumps to pump out water that sprays out of a nozzle directly onto plants

• precision application, supplements can be introduced into the water, efficient (25% or less evaporation), can be programmed to run at certain times of day

• larger up front cost, can include machinery run with electricity use/fossil fuels, nozzles can clog, pivot systems can wear ruts in soil, mostly available in developed countries

drip irrigation

underground pipes with micropores in them, sweat onto roots

• very low evaporation rate, reduces nutrient leeching, no land grading needed

• very expensive, clogs easily, requires mechanization, placement makes any other processes difficult, prevents infiltration

waterlogging

overwatering plants seals air pockets needed for plants to perform cellular respiration, roots die and plants cannot grow

can be fixed by drying out fields and using different irrigation methods

salinization

salt builds up on soil, when there is a lot of water but also a lot of evaporation, salt is left behind and begins to build up on surface, salty desert area is created and plants cannot grow

can be remediated by consistently flushing with freshwater until salt is rinsed out again, planting salt tolerant plants

overfishing

harvesting a species of fish at a greater rate than the population can naturally reproduce and replenish. population will decrease and can lead to extinction

methods of fishing

• pole and line

• long line

• gillnets

• purse seine

• pots and traps

• dredging

• pelagic trawl

• bottom trawl

• (last three are most harmful, especially bottom trawling)

bycatch

non target species caught by fishing

what issues are associated with overfishing?

• significant bycatch issues

• bottom of sea floor can be destroyed and damaged by bottom trawling

aquaculture

the farming of fish, shellfish, mollusks, crustaceans, by individual or corporation with the intent to sell the farmed organisms for profit

• large numbers close together, the water can pollute waterways with excess nutrients and cause algal blooms/hypoxic conditions

• uneaten food pellets can fall to bottom and pollute waterways

• farmed organisms may escape from pens and interbreed or compete with wild organisms (this can be an issue especially with GMOs)

• density means infectious diseases and parasites spread more quickly and easily, must be controlled through antibiotics, medication residue can contaminate waterways, diseases in farmed organisms may spread to wild populations

• SOLUTION can be recirculating systems where it is enclosed meaning farmed or GMO fish will not mix with wild fish. it also filters the waste which prevents disease and nutrients from spreading and causing contamination or eutrophication