Lecture 2 - ecosystems vs agriculture

Question 1

3 major drivers of climate change

Answer 1

1) agriculture
2) food production
3) deforestation

Question 2

what is a possible natural climate solution?

Answer 2

changing land use and management - especially forest management

Question 3

what temperature margin has been defined as a cost effective level of mitigation?

Answer 3

<2°C

Question 4

what are the 5 climate mitigation pathways with co-benefits?

Answer 4

1) reforestation
2) avoided forest conversion
3) natural forest management
4) avoided peatland impacts
5) cropland nutrient management

Question 5

can you put a value on soil?

Answer 5

cant put a numerical value on things that we critically depend on - they have an infinite value

Question 6

Humans depend on ecosystem services what do ecosystem services depend on?

Answer 6

• ecosystem services are ultimately all reliable on both soil and vegetation functions

Question 7

what has a significant role in almost all ecosystem services?

Answer 7

soil

Question 8

examples of 6 ecosystem services that crucially rely on soil?

Answer 8

1) disturbance regulation
2) water regulation
3) erosion control and sediment retention
4) soil formation
5) nutrient recycling
6) food production

Question 9

what is agro-ecology?

Answer 9

Building crop production systems on the sustainable principles of natural ecosystems

Question 10

what 5 plant soil relationships do we need to understand?

Answer 10

i) Understand and better manage global carbon and nutrient cycles
ii) Conserve soil and natural ecosystems
iii) Sustainably feed a rapidly increasing human population
iv) Reduce carbon and nutrient emissions from agriculture
v) Restore sustainability and biodiversity of ecosystems and agriculture

Question 11

what is our primary goal, resource or economic sustainability?

Answer 11

resource sustainability, economic sustainability is secondary

Question 12

where has much of the research on sustainable agriculture taken place?

Answer 12

in developing countries- where people cannot afford the kinds of chemicals, tractors, energy use etc. that characterises modern intensive farming
-Interesting that other systems in developing countries actually may bring solutions to our ‘high tech’ systems

Question 13

what are four types of differences in our understanding of agricultural and ecosystem soil-plant relationships?

Answer 13

1) definitions - what is soil?
2) evaluations
3) assumptions
4) characteristics

Question 14

how do definitions of soil differ?

Answer 14

Depends who you are and what you do with it 
e.g. Engineer = Drift & unconsolidated material 
Soil scientist (pedologist) = mixture of mineral and organic compounds undergoing 	complex physical and chemical transformations.
Agronomist (farmer) = depth to which cultivation takes place and the medium for crop nutrient and water supply.
Ecologist = below-ground ecosystem which provides habitats for plant, animal and microbial communities and controls ecosystem productivity and biogeochemical cycles.

Question 15

how might evaluations of soil differ?

Answer 15

A soil which is good for agriculture is not necessarily of great ecological value, Farmers aim to maximize profit and production.
Ecologists value diversity of flora and fauna and seek sustainability
We need to be aware of these different value systems and the ways they are used.
e.g. how ecologists and agronomists look at a piece of land is completely different

Question 16

how might soil assumptions differ?

Answer 16

• Assumptions which hold true or are valid in an agricultural context may not apply to natural systems.
• Likewise, proven attributes and features of natural ecosystems may not be retained in agriculture
  e. g. drainage was previously assumed to improve soil but we now know it releases C stores and normally reduces biodiversity

Question 17

how do characteristics of agriculture and ecosystem soil-plant relationships differ?

Answer 17

The characteristics of agricultural and natural soil and plants vary massively

e. g soil. in agricultural soil stones are removed and natural soils are often very stony
e. g. plants - grown as monocultures in agriculture and natural ecosystems are often mixtures of species

Question 18

what is the sparing land method?

Answer 18

suggested that intensification of agriculture to ‘spare’ natural ecosystems from conversion to agriculture is better than expanding less intensive agriculture into natural ecosystems

Question 19

what would land sparing do the agricultural footprint?

Answer 19

may reduce the overall size of the “footprint” of agriculture but the resulting “heavy footprint” of the intense cultivation areas often involves total destruction of native habitats

Question 20

how does land sparing effect crop failures?

Answer 20

concentrates risks of major crop failures

Question 21

what are the issues with agricultural intensification under the land sparing method?

Answer 21

• Soil degradation reduces crop production and soil fertility- so more land needs to be converted to agriculture to compensate for this loss and more fertilizer added. This leads to more land and water degradation and loss of ecosystem services
• high ecological costs

Question 22

describe the food-biofuel conflict

Answer 22

Over 30% of maize (corn) grown in USA from 2009 is used to make bioethanol
GLOBAL biofuels in 2008 contributed only 0.6% of total liquid fuel production but inflated staple grain prices by more than 25%
Cereals (wheat, maize, rice etc.) provide 48% of human food energy.
World per capita cereal production has peaked and is not keeping up with population growth. Now biofuel production is also using food

Question 23

there is no universally accepted definition of sustainable agriculture but what is it viewed as?

Answer 23

Producing abundant food without depleting the earth’s finite resources or polluting its environment whilst providing dependable incomes to growers

Question 24

who came up with the current uk sustainable agriculture policy?

Answer 24

DEFRA

Question 25

why cant we expand intensive agriculture to feed the world

Answer 25

-Finite resources (land, soil, water, nutrients, energy)