CPSC 112 Final Exam UIUC UPDATED
Exam Questions and CORRECT Answers
Furrow Irrigation - Correct Answer- Crops in row slightly elevated, sloped "furrows" between
rows convey water, over 50% of the US irrigated farmland, water rights in the arid west
which soil textures have the highest plant available water - Correct Answer- clay, sand, sandy
loam, loam, clay loam, silty loam
Plant available water - Correct Answer- field capacity-permanent wilting point
options for increasing WUE (water use efficiency) - Correct Answer- agronomic =
yield/amount of water applied
physiological = unit of biomass/unit of water transpired
photosynthetic = unit of C assimilation/unit of water transpired
increase numerator or decrease denominator
3 E's of sustainability - Correct Answer- equity (society, people), economy (profit),
environment (planet)
properties of agricultural systems with agroecology - Correct Answer- productivity, stability,
sustainability, and equitability
crop rotation benefits in organic agriculture - Correct Answer- replenishment of N, pathogen
reduction, soil quality improvements, soil fertility
general idea of 0.4% (or 4 per 1000) French initiative - Correct Answer- if we increase soil
carbon by 4% per year, then we can halt the annual increase of CO2 in the atmosphere
organic standards - Correct Answer- no inorganic fertilizers, no synthetic chemicals
(herbicides, pesticides, fungicides - but some bio based products okay), and no GMOs
, benefits of using legumes in organic agriculture - Correct Answer- fixes N, helps to control
weeds, improve soil structure, erosion control,
sustainable intensification - Correct Answer- increasing yields while decreasing
environmental impacts
method of calculating yield gaps - Correct Answer- yield potential-actual yield obtained by
farmers
most important variables influencing energy efficiency and net energy output - Correct
Answer- water use, water loss, net energy yield = energy output in grain-sum of all energy
inputs
options for increasing water productivity in rain-fed systems - Correct Answer- 1) Increase
yields
2) Increase precipitation capture (e.g.
mulching soil surface)
3) Increase soil water storage (e.g.
through increased SOM)
4) Minimize losses (e.g. decrease
runoff/evaporation by increasing
infiltration rates with no-till)
soil greenhouse gases (GHGs) occurring in agriculture - Correct Answer- carbon dioxide (soil
respiration, primarily offset by crop CO2 fixation), methane (CH4, flooded soils (rice) and
animal production), and nitrous oxide (N2O, arable soils , primarily related to N fertilizer and
manure application)
why is N2O such a concern - Correct Answer- it often represents over 50% of total CO2
equivalents for corn production, also somewhat unavoidable because it is produced during
nitrification and denitrification processes (especially when soil N is high), N fertilizer is
needed for high yields yet ag is targeted as possible climate change mitigation opportunity
Exam Questions and CORRECT Answers
Furrow Irrigation - Correct Answer- Crops in row slightly elevated, sloped "furrows" between
rows convey water, over 50% of the US irrigated farmland, water rights in the arid west
which soil textures have the highest plant available water - Correct Answer- clay, sand, sandy
loam, loam, clay loam, silty loam
Plant available water - Correct Answer- field capacity-permanent wilting point
options for increasing WUE (water use efficiency) - Correct Answer- agronomic =
yield/amount of water applied
physiological = unit of biomass/unit of water transpired
photosynthetic = unit of C assimilation/unit of water transpired
increase numerator or decrease denominator
3 E's of sustainability - Correct Answer- equity (society, people), economy (profit),
environment (planet)
properties of agricultural systems with agroecology - Correct Answer- productivity, stability,
sustainability, and equitability
crop rotation benefits in organic agriculture - Correct Answer- replenishment of N, pathogen
reduction, soil quality improvements, soil fertility
general idea of 0.4% (or 4 per 1000) French initiative - Correct Answer- if we increase soil
carbon by 4% per year, then we can halt the annual increase of CO2 in the atmosphere
organic standards - Correct Answer- no inorganic fertilizers, no synthetic chemicals
(herbicides, pesticides, fungicides - but some bio based products okay), and no GMOs
, benefits of using legumes in organic agriculture - Correct Answer- fixes N, helps to control
weeds, improve soil structure, erosion control,
sustainable intensification - Correct Answer- increasing yields while decreasing
environmental impacts
method of calculating yield gaps - Correct Answer- yield potential-actual yield obtained by
farmers
most important variables influencing energy efficiency and net energy output - Correct
Answer- water use, water loss, net energy yield = energy output in grain-sum of all energy
inputs
options for increasing water productivity in rain-fed systems - Correct Answer- 1) Increase
yields
2) Increase precipitation capture (e.g.
mulching soil surface)
3) Increase soil water storage (e.g.
through increased SOM)
4) Minimize losses (e.g. decrease
runoff/evaporation by increasing
infiltration rates with no-till)
soil greenhouse gases (GHGs) occurring in agriculture - Correct Answer- carbon dioxide (soil
respiration, primarily offset by crop CO2 fixation), methane (CH4, flooded soils (rice) and
animal production), and nitrous oxide (N2O, arable soils , primarily related to N fertilizer and
manure application)
why is N2O such a concern - Correct Answer- it often represents over 50% of total CO2
equivalents for corn production, also somewhat unavoidable because it is produced during
nitrification and denitrification processes (especially when soil N is high), N fertilizer is
needed for high yields yet ag is targeted as possible climate change mitigation opportunity
