Lecture 2 Flashcards
land use change over the last 8000 years =
reduction in wild lands (forests), semi-natural
increase in arable and pasture and densely settled
building crop production systems on the sustainable principles of natural ecosystems consequences
-reduction in productivity
- reduction in biodiversity?
difficult to please all
what do we need to understand to achieve sustainable yet effective agro sector
- understand & better manage global carbon & nutrient cycles
- conserve soil and natural ecosystems
- sustainably feed growing population
- reduce carbon and nutrient emissions from agriculture
- restore sustainability & biodiversity of ecosystems & agriculture
natural ecosystems are ___ self-sustaining and perpetually renewing and adapting
naturally
– we need to learn from this to be effective stewards of earths resources
has sustainability been a major goal in agriculture in past?
no, been on productivity.
- recently now on sustainability
- -but focussed on money, economical value of products
research of ‘healthy’ soil in developed countries
little research, more research in developing countries as they can’t afford high use of fertilisers (chemicals), energy use etc
is soil perceived the same from everyone?
no,
agronomist (farmer) diff to ecologist
ecologist like virgin tropical rainforest
agronomist like intensive agriculture
many of the ecosystem properties that farmers manipulate to enhance productivity result in
loss of diversity and ‘ecological value’ but ensure cheap food –> but what value do we put on sustainability and nature
agricultures role in society extends beyond
production of food and fibre
- management of renewable natural resources, conserve biodiversity, landscape aesthetics and regulates hydrological flows
RENTING et al 2009
No value for these, so famers payed for producing such services
positive and negative environmental values of agriculture?
- UK agriculture generates environmental value of £650 million per year
- agriculture damage due to ghg emissions estimated £2.07 billion per year (ANGUS et al 2009)
MORE WORSE THAN GOOD
Current UK government 25 year environment plan
- improve soil health
- by 2030 all england soils managed sustainability = unrealistic! massively
there is often more biology and biodiversity above/below ground
belowground
is there a Royal Society for the Protection of Soil Organisms
No
characteristics of soil: agricultural soil vs ‘Natural’ ecosystems soil
- Natural more variable, not having manipulations
- natural = more organic matter
Characteristics of plants in agricultural vs natural soil
- agricultural =
- grown in monocultures
- -annual herbaceous
- -high yield
- shallow roots
natural
- -mixed sp. co-existiing
- -perennial plants
Even urban areas now host more ____ than our intensively managed farmland
biodiversity
alternative to less intensive agriculture in natural ecosystems
intensification of agriculture to ‘spare’ natural ecosystems
- land sharing vs land sparing
- land sharing not been looked into enough
land sparing concentrates risks of
major crop failures
- drought
- hurricanes
soil degradation reduces crop ___ and soil ____
crop production and soil fertility
– so more land needs to be converted to agriculture to compensate for this loss and more fertiliser added
UK post 1940’s agricultural intensification and productivity gains have had
high ecological costs
- loss of biodiversity in birds, wildflowers are noticed but loss of topsoil, earthworms, mychorriza go unnoticed
UK crop yields have__
plateaued - fake in recent years due to poor weather & soil constraints
The food-biofuel conflict
- over 30% of maize (corn) grown in the USA from 2009 is used to make bioethanol
- 18% fall in world grain stocks from 2000-2012 at the same time a 14% increase in world pop
- now less than 3 months stock of food globally
cereals (wheat, maize, rice etc) provide __% pf human food energy
48%
- world per capita cereal production has peaked and is not keeping up with population growth
- now biofuel production is also using food
what do we mean by sustainable agriculture?
no universally accepted definition BUT
‘producing abundant food without depleting the earths finite resources or polluting its environments whilst providing dependable incomes to growers’
finite resources (land,soil,water,nutrients,energy) mean we cannot merely ___
expand intensive agriculture to feed the world
- more of the same isn’t an option
- must produce more food efficiently with a growing population
