ecology and agriculture Flashcards
agriculture
= the science or practice of farming including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool and other products
history of agriculture
- 200,000ya evolution of homo sapiens
- 15,000-10,000ya = the first agricultural revolution, developed independently in many parts of the world
- change in relationship between humans and the environment
- exponential population growth and increase in caloric intake in the 20th and 21st century led to the intensification of agricultural output
global surface area allocation for food production
- agriculture takes up 50% of habitable land (rest is 37% forests, 11% shrub, 1% freshwater, 1% urban)
- 77% agricultural land is used for livestock (caloric supply of animal products is 17%)
food security issues
- linked to climate change
- LICs issue is amount of food needed for population to survive
- HICs issue is availability of ‘luxury’ imported food
the green revolution
- from 1961 to 2012 the world uses 68% less land to produce same amount of food
- crop yields increased significantly due to the harnessing of the Haber-bosch process (inorganic ammonium nitrate fertilisers) and use of rock phosphorous
- more efficient production but less efficient nutrient use than organic farming
how have yields increased
- crop improvement
- fertiliser application
- mechanisation
- irrigation
- use of pesticides
global fertiliser use
- global increase in use of inorganic fertilisers
- collapse of soviet union meant Cuba had not imported synthetic fertilisers, food crisis, went organic (organoponicos)
pesticides
- increase in use of herbicides, insecticides, fungicides
- recent shift towards GM crops in many EU countries (banned certain pesticides)
irrigation systems
- allowed for stable crop growth in arid areas of the world where rainfall is infrequent and variable
- agriculture is the largest consumer of freshwater on the planet
- rice uses the most water globally, very water demanding
- often depends of aquifers, can cause geopolitical conflict at times of water stress
aquaculture
- fastest growing food production sector
- fish farms
- controlled conditions, high yields and growth rates
- environmental issues, parasitism
industrial agriculture
= a form of modern farming that refers to the industrial production of livestock, poultry, fish and crops. technoscientific, economic and political methods
environmental nutrient enrichment from fertilisers
- nutrient richness historically highest in tropics where there are more legumes and lightning strikes, now in areas with lots of intensive agriculture
- 50% nitrogen lost from fertilisers, 25% into aquatic systems, 25% released as nitrous oxide from soil
- CO2 also released from the process of making fertilisers
insect pollinators
108 main crops, insects are
- essential for 13
- highly important for 30
- moderately important for 28
- slightly important for 21
- neonicotinoid pesticides negatively impact honeybee survival (banned in EU)
current deforestation
- linked to agricultural expansion
- tropical regions
- often profitable in the short term
- grazing, crops such as palm oil, biofuels
the carbon debt of converting land to biofuels
- only unfavourable land used to grow biofuel crops, natural remaining ecosystems
- net loss of carbon from disturbing natural ecosystems often more than carbon savings linked to biofuels
mangrove deforestation
- 30% linked to aquaculture expansion
- also rice and palm oil
agriculture and diseases
- with more deforestation and displacement of wild animals and more livestock there is more of a risk of zoonotic diseases
reducing food waste
- 1.3bn tonnes annually
- 23% food wasted in Wales
- in developing countries most food is lost during early post harvesting and processing
- in developing countries food is mostly lost during retail and processing
shift in diets
- increase in income linked with increase in consumption of animal products and ‘empty calories’
- GHG emission highest from meat and fish
modelled system with no livestock in US, plant based diets
- food production increased 23%
- agricultural GHG emissions reduced by 28%
- overall GHG emissions reduces by 2.6%
- more energy in the system, excess of calories
- greater number of nutritional deficiencies, not everyone able to keep up with nutritional demands on plant based diet
agroforestry
- system with high output and low environmental impact
- increased yields and biodiversity
- study of tropical cacao agroforests showed that non-crop biodiversity only decreased with one group of species
sustainable intensification
= involves increasing yields from the same area of land while reducing negative environmental impacts and increasing provision of environmental services
- a way of coping with future population growth
organic farming
- no pesticide, fertiliser or medicinal inputs
- generally lower yields
- regenerative agriculture aims to restore nutrients and keep them in the system, more efficient overall
precision farming
= the precise application of nutrients, pesticides and water can minimise inputs while maximising outputs and reducing negative environmental impacts
- also assessment of suitability of land for different crops, management at a smaller scale
urban agriculture, hydroponics
= the process of growing plants in sand, gravel or liquid with added nutrients, but not soil
- space saving
- growing close to consumption
- unsure about sustainability of using artificial light sources
