AGRON 360 EXAM 1 QUESTIONS AND
ANSWERS
the diffuse double layer indicates that against the CEC sites there is much high
concentration of _____ than ____ - Answer-cation; anion
For effective plant growth, soil solution needs to contain dissolved water and plant
available - Answer-nutrients
A simple, easy yet balanced reaction for photosynthesis - Answer-6CO2 + 6H2O -->
C6H12O6 + 6O2 (6O2 is a waste)
High gas exchange generally occurs around roots when the soil's texture is - Answer-
blocky
The texture size that retains the most plan available water is - Answer-clay
"K-fixation" in illite (or mica) refers to - Answer-potassium holding adjacent illite crystals
together
A clay mineral ("phyllosilicate") with LOTS of shrink-swell -- causes a dry soil to crack a
lot -- is - Answer-smectite
Put Ca2+, Mg2+, Na+, H+, NH4+, and K+ in their lytropic series order - Answer-Ca2+ >
Mg2+ > K+ = NH4 > Na+ > H+
LD50 stands for - Answer-is the dose given all at once that kills 50% of the test
organisms
anchor/support - Answer-Role of soil: provide support to the plant
gas exchange - Answer-Role of soil: below ground-respiration, above ground-
photosynthesis, O2 going into soil and Co2, CH4 going out
symbiosis - Answer-Role of soil: providing biological system that is mutually beneficial
nursery - Answer-Role of soil: temperature control and growth environment
nutrients - Answer-Role of soil: supplies 12 of the 17 essential nutrients plants need
water availability - Answer-Role of soil: provide water for plant without complete draining
or over flooding, 100 tons of water per 1 ton of corn
ANSWERS
the diffuse double layer indicates that against the CEC sites there is much high
concentration of _____ than ____ - Answer-cation; anion
For effective plant growth, soil solution needs to contain dissolved water and plant
available - Answer-nutrients
A simple, easy yet balanced reaction for photosynthesis - Answer-6CO2 + 6H2O -->
C6H12O6 + 6O2 (6O2 is a waste)
High gas exchange generally occurs around roots when the soil's texture is - Answer-
blocky
The texture size that retains the most plan available water is - Answer-clay
"K-fixation" in illite (or mica) refers to - Answer-potassium holding adjacent illite crystals
together
A clay mineral ("phyllosilicate") with LOTS of shrink-swell -- causes a dry soil to crack a
lot -- is - Answer-smectite
Put Ca2+, Mg2+, Na+, H+, NH4+, and K+ in their lytropic series order - Answer-Ca2+ >
Mg2+ > K+ = NH4 > Na+ > H+
LD50 stands for - Answer-is the dose given all at once that kills 50% of the test
organisms
anchor/support - Answer-Role of soil: provide support to the plant
gas exchange - Answer-Role of soil: below ground-respiration, above ground-
photosynthesis, O2 going into soil and Co2, CH4 going out
symbiosis - Answer-Role of soil: providing biological system that is mutually beneficial
nursery - Answer-Role of soil: temperature control and growth environment
nutrients - Answer-Role of soil: supplies 12 of the 17 essential nutrients plants need
water availability - Answer-Role of soil: provide water for plant without complete draining
or over flooding, 100 tons of water per 1 ton of corn
