Food and agriculture

Question 1

What are the main staple food in terms of E%?

Answer 1

Main staple food (in terms of energy) in two average diets

African: mostly cereals, second roots and tubers and last animal products

Western: mostly animal product, second cereals and last roots and tubers.

Question 2

What is the meat mostly produced?

Answer 2

Pig meat – the biggest meat in world today. There is a very high concentration and specialization in world pig production today. In china, middle of US and middle of EU.

Question 3

How is milk and beef production interlinked?

Answer 3

Milk and beef production are closely interlinked – more efficient to have beef from a dairy system than from a pure beef system. ~50% of global beef production originates from the dairy sector.

Question 4

What is the different soil degradation?

Answer 4

Soil degradation: overview of types and mechanisms
1. Displacement of material
	water erosion (loss of topsoil, terrain deformation)
	wind erosion (loss of topsoil, overblowing)

2. Physical deterioration
   compaction, crusting and sealing (caused by heavy machines, raindrops (due to lack of soil cover) and cattle trampling)
   waterlogging (caused by human intervention in natural drainage systems)
3. Chemical deterioration
   loss of nutrients and/or organic matter
   Salinization (caused by improper irrigation, seawater/saline groundwater, decreased evapotranspiration due to human activities in areas with salt-containing soils or saline groundwater)
   acidification (over-application of acidifying fertilizers)
   pollution (e.g. excessive use of pesticides)

Question 5

What are some GHG from agriculture?

Answer 5

GHG from agriculture – livestock and soils most important
Nitrous oxide N2O – mostly soils 1kq N2O 300kg CO2
Metan CH4 – ruminants and manure 1kg CH 25kg CO2
CO2 from fossil fuels less significant
Ruminant feed digestion
Has complex microbial community. Bacteria, cliliate protozoa, anaerobic fungi, archea, viruses. Plant material broken down results in volatile fatty acids, NH3, H2 and CO”.

Question 6

How is N2 fixation?

Answer 6

Anthropogen production of reactive nitrogen
Industrial fixation of N2
Biological fixation of N2, leguminoses (soybeans, clover, peas etc)
NOx produced from N2, in combustion > 1200 C (most) and mobilization of N in the fuel.

Reactive N-emissions from agriculture
Emission of nitrous oxide: global warming
Input N-fixation: industrial + biological
Emission of ammonia: eutrophication, acidification.
Leaching of nitrate: Eutrophication, contamination of groundwater

Increasing transports of reactive nitrogen in world water systems.