Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

APS 346 Sustainable Agro-Ecosystems > Lecture 14: > Flashcards

Lecture 14: Flashcards

1
Q

what is sustainable agriculture?

A
  • Producing abundant food without depleting the earths finite resources or polluting its environment whilst providing dependable incomes to growers
  • a sustainable agriculture system should be able to be maintained for the foreseable future of the Anthropocene and not compromise the abilities of future generations to feed themselves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Climate change impacts on global food security: estimated number of people more at risk of hunger by 2080 due to climate change

A

200-400 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Climate change impacts on global food security: The Perfect Storm

A

Sir John Beddington
- increased energy, water and food demand with added pressure form climate change
- but is acc more complicated than this (impacts on land area, soils, water and pests, weeds and diseases)
-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Climate change impacts on global food security: likely to drive ___ yields and __ crop vulnerability to failure

A

down

increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Climate change impacts on global food security: replacing fossil fuels with some kinds of biofuels will often compete with

A

crops for land area and fertile soils but may reduce effects of energy use on climate change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Climate change impacts on global food security: decreasing numbers and effectiveness of herbicides, fungicides and pesticides threaten

A

yields

-whilst more fertiliser use (developing countries) can increase yields it often contributes to GHG emission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

anticipated loss of soil/ land area

A
  • extreme weather – drought / high rainfall erosion events
  • warming – increased decomposition of soil organic matter
  • sea level rise – thermal expansion and melting ice caps and glaciers
  • –suggested that 2m of sea level rise may occur by 2100
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

increased sea level: displacements of __ by 2100 due to 2m rise

A

187 million people
– loss of fertile deltas and coastal plains
(move to land being used for agriculture?)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Sea water rise: Fens

A

-37% of outdoor grown veg for the UK
- much of which is as / below sea level
Other areas: Florida

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Soil conservation technologies:

A
  • no-till cultivation
  • strip-cropping
  • contour planting
  • terracing
  • mulches
  • cover crops
  • leys
  • agro-forestry
  • wind-breaks

– many techniques try to mimic natural ecosystems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Nutrient supply for sustainable agriculture: ways of improving

A
  • Legumes and green-manures in rotations to build and retain fertility
  • Agro-forestry especially with legume trees
  • P mobilising plants, mycorrhizas & bacteria
  • use of rock-dust fertilisation from abundant rock sources like basalt
  • waste recycling, composting and manures organic matter nutrient storage and ion exchange capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Nutrient supply for sustainable agriculture: Phosphate fertilisers in soil

A
  • fertiliser is being added at much greater rates than crops use it, most becomes bound in the soil, but more needs to be added because in modern intensive agriculture P use is inefficient.
  • erosion losses of P enriched topsoil
  • for developing countries P fertiliser would be helpful but expensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Nutrient supply for sustainable agriculture: Basalt

A
  • rock dust addition esp for weathered soils
  • increases available P
  • reduces P sorption
  • reduces soil acidity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Water resources for sustainable agriculture:

A
  • no new land or water to develop so have to make good use of what we have
  • more than 70% of all available water is used in world agriculture
  • to produce 1ha of corn, 5million l of water/ha
    Pimmentel & Pimmentel 2006
    -more water used is steadily increasing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Water resources for sustainable agriculture: Wheat yields effected by irrigation

A
  • improve yields
  • UK wheat growing can yield 11.5-14.8 Tonnes per hectare
  • at 13 tonnes per hectare we can produce enough wheat to feed over 150 people per hectare at current consumption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Water resources for sustainable agriculture: Irrigation often requires

A

pumping- frequently using groundwater resources at rates that are unsustainable

17
Q

Water resources for sustainable agriculture: Salt accumulation

A
  • salinity increases as salt from groundwater is deposited there
  • destroys soils as crops can then not grow as it is contaminated
18
Q

Water resources for sustainable agriculture:salt water for irrigation

A

solar powered desalination of seawater for irrigation

19
Q

Organic matter for sustainable agriculture:

A
  • need to get organic matter back in soils for it to be sustainable
20
Q

Approx. £___ cost per year of soil degradation in england and wales

A

£1.2 billion

  • Mainly due to
  • – loss of organic content of soils
  • – compaction
  • – erosion
  • –other
21
Q

loss of organic matter leads to __

A

soil compaction

22
Q

do the majority of uk arable farmers analyse their soils to look at organic matter contact?

A

NO

23
Q

__ inputs are the main control on amounts of soil organic carbon in intensive agriculture

A

carbon

  • – more u put back in, the more that will be there
  • -different sources vary stability
  • -farmyard manure is more chemically stable as it has been processed (digestive system and guts)
24
Q

fertiliser / compost/ fertiliser and compost

A

compost and fertiliser

  • -compost reintroduces organic matter
  • -NPK alone (Fertiliser) restricted by lack of organic matter
25
Q

how feasible is it to substantially increase soil organic carbon storage in agriculture? optimal strategies to rapidly accumulate soil organic carbon?

A
  • Agroforestry
  • Leys
  • Legumes
  • —Leys: countries where food plentiful OK, those w acute food shortage may not be able to take time off growing
  • –negative feedbacks due to climate change
26
Q

Biota Pests, disease and weeds: Conventional agriculture is starting to fail WHY

A
  • Conventional agriculture is starting to fail
  • –resistance to chemicals & banning of use of some chemical presents increasing problems for crop production
    • diverse cropping systems and rotations to reduce bio
  • Hicks et al 2018: Black grass infestation. herbicide resistance: area treated is by herbicide rises, density of weed correlates to herbicide resistance, costly
27
Q

neonicotinoid

A

= insecticide, sprayed on seeds, as grow, enters plants, repels insects BUT damaging to bees
-also effects earthworms. Wang et al 2015. Toxic if conc are high enough

28
Q

Beneficial biota: for nutrient cycling

A
  • legumes and green-manures fixing & recycling nitrogen
  • crop rotation, cover cropping and co-cropping (e.g. cereals undersown with clover)
  • phosphorous mobilising plants
  • phosphorous and plant growth promoting rhizobacteria
29
Q

Beneficial biota: Soil structure, aggregation, drainage and C sequestration

A
  • earthworms
  • mychorrhizas
  • leys and legumes, cover crops and agro forestry
30
Q

undersowing crops and other plant example (cereal and nitrogen fixing plant)

A

maize-soybean

  • strip cropping system,
  • 42% increase on usual yield of same area of land
  • with the correct optimal arrangement
31
Q

energy: Pretty et al 2005

A

our lifestyle is currently totally oil dependent

  • 80-95% of all transport is fuelled by oil products
  • 99% of our food involves oil / gas for fertilisers, agrochemicals, tilling, cultivation and transport
  • nearly 30% of UK goods vehicle miles are used to transport agri-food products
32
Q

Oil consumption

A

still increasing, also increasing in Gas

  • -reneweable increasing but v small
    • BP 2017
33
Q

environmental footprint: wheat-to-bread

A
  • fertiliser huge amount (43%)

- 57% from on-farm acitivites

34
Q

biofuels:

A

use food crops to make fuel
-waste? only makes 4% of worlds fuel

– future –> non-edible crops

35
Q

Crop productivity depends on

A
  • soil
  • nutrients
  • organic matter
  • biota
  • water use
  • energy
  • people
  • weather
36
Q

food supply is dependent on how we use production =?

A
  • whether we use it as human food, animal feed biofuels

- no global stocks/ reserves to last significant time

37
Q

new people coming into farming?

A

no enough

  • not enough studying plant sciences
  • none of UKs top research unis offer horticulture
  • research money: need more funding to look at different crops, especially those grown in developint countries
38
Q

food wastage: in the UK alone food woorth over ___ is wasted each year

A

10 billion

  • -accounts for 5% of UKs ghg emsisions
  • –if we stop wasting food we could pay farmers a fair price (they only receive 4billion)

APS 346 Sustainable Agro-Ecosystems (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions