Soils Final

Question 0

2 classes of organic contaminants

Answer 0

Industrial

Pesticides

Question 1

Xenobiotics

Answer 1

Artificially produced organic compounds

Question 2

7 possible fates of xenobiotics when released into the soil environment

Answer 2

Vaporize
Absorbed by soil
Leach down 
Break down into other compounds
Broken down to simple products via microbe ingestion
Erosion losses
Taken up by plants

Question 3

Remediation of contaminated soil 5 basic ways

Answer 3

Ex. Situ
In situ
Bioremediation 
Biostimulation
Phytoremediation

Question 4

Ex. Situ

Answer 4

Dig up, haul off, and replace or remove soil

Question 5

In situ

Answer 5

On site remediation. Method when can’t remove the soil

Question 6

Methods of in situ remediation

Answer 6

Decontamination
(Put down chicken litter)
Soil sequestered
(Treatments in the soil until contaminants are broken down

Question 7

Surfactants

Answer 7

Help dissolve and disassociate some xenobiotics. Used in soil sequestering

Question 8

Bioremedition

Answer 8

Use of organisms to remove or neutralize pollutants fro contaminated site
Do things to enrich the soil in situ

Question 9

Biostimulation

Answer 9

Do things to increase biological activity in soil such as lime or fertilizer

Question 10

Phytoremediation

Answer 10

Use plants to remediate soil. Take up and break down compounds

Question 11

Problems with land applications of sewage sludge

Answer 11

sludge has contaminants such as xenobiotics and heavy metals (Cd, Ar, Pb)

Question 12

2 basic types of land fills

Answer 12

natural, unsecured

contaminant, secured

Question 13

natural , unsecured landfill structural characteristics

Answer 13

flat grounds
doesn’t flood
clay sublayer with a loamy topsoil

Question 14

contaminant, secured landfill structural characteristics

Answer 14

excavated out
lined with a heavy vinyl or concrete
wells that go down into the pit
constantly check levels of dangerous contaminants

Question 15

Soil properties favorable for landfills

Answer 15

depth 1.5 meters or more
CEC thats high with good microbe environment
soil texture that’s loamy on top and clay underneath

Question 16

Problem of radon gas from soils

Answer 16

causes lung cancer

Question 17

Cause of radon gas

Answer 17

emission from some soils such as shale

Question 18

potential radon problem soils

Answer 18

highly deformed metamorphic residium soils
marine sediments
certain limestones
coal or oil bearing shales

Question 19

remediation idea of radon exposure

Answer 19

seal cracks in foundations
houses with crawl spaces rather than slab or basement
good ventilation

Question 20

fauna

Answer 20

soil animals

Question 21

flora

Answer 21

soil microplants and microorganisms

Question 22

5 classes of soil organisms

Answer 22

macrofauna
mesofauna
microfauna
macroflora
microflora

Question 23

macrofauna examples

Answer 23

mice
moles
beetles
termites

Question 24

mesofauna examples

Answer 24

mites
springtails
pot worms

Question 25

microfauna examples

Answer 25

nematodes
amoebae
flagellates

Question 26

macroflora

Answer 26

feeder roots of higher plants

mosses

Question 27

microflora

Answer 27

root hairs
algae
fungi
bacteria
actinomycetes
cyanobacteria

Question 28

Things that affect soil organisms

Answer 28

nitrification
denitrification
mineralization
soil aggregation
water infiltration
increased carbon

Question 29

2 main groups of soil organisms based on where they get C

Answer 29

autotrophic

heterotrophic

Question 30

autotrophic

Answer 30

“self feeding”
photoautotrophs- obtain energy from CO2 fixation
chemoautotrophs- N, S, Fe fixation

Question 31

heterotrophic

Answer 31

cannot fix carbon and use organic carbon for growth

Question 32

Primary benefits of soil organisms

Answer 32

organic matter decomposition
nutrient mineralization
breakdown, detoxifying pesticides and other deadly compounds
improving soil structure, erosion resistance, aeration
help plants obtain nutrients

Question 33

Relative rates of organic matter decomposition

Answer 33

sugars/starches > proteins > cellulose > fats/waxes > lignin/cutin

Question 34

Breakdown of plant debris (detritus)

Answer 34

1. main concern: primary consumers: bacteria, fungi, shredders (mites, earthworms, etc)
2. Secondary consumers: microflora and carnivores (mites, centipedes that consume small insects and nematodes)
3. Tertiary consumers: ants, scorpions, birds, etc that consume soil macrofauna

Question 35

decomposition of plant residue

Answer 35

role of residue composition

limit of C/N ratio or residue before potential for temporary tie up of soil N (25/1)

Question 36

conditions affecting growth and populations of soil microorganisms

Answer 36

soil organic matter (detritus, humus)
oxygen
moisture
temperature
pH, CEC, Na etc

Question 37

practices to increase biodiversity and populations of soil organisms

Answer 37

cover crops
reduce tillages
crop rotation with legumes
liming acidic soils
irrigation
good soil fertility program
soil erosion control