Agricultural sustainability Flashcards
What percentage of the GHG emissions of the UK does DEFRA estimate to come from agriculture?
Current DEFRA estimates that circa 10% of UK greenhouse gases are from agricultural sources.
This underestimates the role of this sector in overall emissions because key processes such as fertiliser production (via Haber-Bosch) are counted in the Business sector.
What proportion of the carbon footprint of a loaf of bread comes from wheat growth according to Goucher et al (2017)?
Approximately 57% of the carbon footprint of bread production was estimated to be from the growth of wheat, comprised of 43% from fertiliser production and nitrous oxide emissions, and 14% from soil cultivation.
How quickly is applied ammonium fertiliser nitrified?
Ammonium has been shown to be nitrified within a week of application.
All N fertilisers applied to soils disappear quickly either through plant or microbial conversion to biomass by leaching/volatilisation or microbial processing.
What is the main function of denitrification?
Denitrification is a respiratory process using nitrogen oxides as alternative electron donors.
What are the main environmental factors affecting denitrification that cause variation in the release of N2O and N2?
Main factors include rainfall affecting the oxygen status of soils as they wet, soil pH, and temperature.
How good are mammals at breaking down cellulose?
Mammals cannot break down cellulose but rely on symbiosis with microbial consortia in their gut to degrade it.
The mammal then competes with the microbes for products such as volatile fatty acids, although they also digest microbial biomass as a source of protein.
Why do cows produce several hundred litres of saliva a day?
One of the main reasons is to maintain pH balance in the rumen.
Why can we not simply kill methanogens in the rumen to solve the issue of methane release from cows?
Simply killing methanogens disrupts the balance of the rumen and results in reduced production of critical volatile fatty acids in the rumen, reducing the efficiency of the system.
