life in soil Flashcards
what are the four main ingredients in soil
air - 25
water 25
mineral 45
organic 5
organic definition
materials alive now or in the past
is adding organic matter a good thing or bad thing
good in the long run, bad in the short run
do humic colloids have high or low CEC
high
do humic colloids buffer soil pH
yes
do humic colloids retain cationic nutrients
yes
how does humus act like glue and stabilize soil aggregates
improves aeration
increase infiltration rate
increase plant avail water
decrease susceptibility to erosion
what does humus slow release (3 nutrirents)
N, P, S
negatives of fresh crop residue
initially negligible cation exchange capacity
little glue
interfere with plant nutrient uptake if incorporated directly into soil (less of a problem if left ontop of mulch)
do plant residues like straw or stardust tie up nitrogen
yes
does manure supply ammonium to plant roots
yes
soil organisms converts fresh plant residues to __________
humus
heterotroph
an organism that obtains the carbon atoms from which it builds its strucutre from organic molecules
chemoheterotrophs
heterotrophs that obtain their energy from chemical reactions like respiration or fermentation
yogurt or mushrooms
photoheterotrophs
heterotrophs that obtain their energy from light
few exotic bacteria
autotroph
an organism that obtains its structural carbon atoms inorganic molecules
chemoautotrophs
autotrophs that get energy from inorganic chemical reaction
thiobacilli
photoautotrophs
autotrophs that obtain energy from light
plants, algae, diatoms
a photoheterotroph needs to grow with a _______ __________ who leaks inorgnic compounds
photoautotrophic partner
prokaryote def
no membrane bound nucleus
eukaryote def
keeps DNA in a membrane bound nucleus
Prokaryote or eukaryote? linear chromosomes
eukaryote
Prokaryote or eukaryote? reproduction through clining and binary fission
prokaryotes
Prokaryote or eukaryote? organelles
eukaryotes
Prokaryote or eukaryote? circular chromosomes
prokakryotes
are there curcular chromosomes in eukaryotes
in organelles yes
do all organisms have ribosomes in them
yes
job of ribosomes
assemble all protiens one amino acid at a time based on instructions copied from DNA into RNA messages (mRNA)
TF DNA can’t tell you ancestral history
F
3 domains
bacteria, archaea, eukarya
When are archaea present in soil
nitrogen cycle
only they can create swamp gas
is prokaryotic biomass equal to funal abundance
yes, prokakryotic biomass is more in ag soisl
of all euakryotes, what organisms appear ot be the most significant
earthworms
when macrofauna digests dead plant matter, does it emerge out of the other end fully digested
no
why is amcrofauna not great at difesting dead plant matter (fully) (chemical)
cellulose
TF macrofauna decreases the speed at which microbes can enter, decompose, and transform the fresh organic matter into CO2
F, increases it
are earthworms macro or microfauna
macrofauna
what types of things do earthworms like to eat
fine particles and organic things
earthworm midden
burrow entrance sign- covered with availible debris
TF worms don’t crap in their own burrows
T
where do earthworms void their poop
surface
do earthworms have an affect on the surface grain size, and if so - how
ingestion of silt and clay VS sand will make the surface finer grained
fewer crop residue = more or less earthworms
less
how much do earthworms like lime
a LOT
does tillage reduce earthworm abundance
yes
do earthworms like hot or cool soil
cool- when its hot they’ll drive deeper into the ground
DDT affect on earthworms
doesn’t affect them directly but compounds in their tissue. Then robins eat them and their eggs become very weak
nematodes
small round worms not related to earthworms
some are root infesting plant parasites
some eat pests
do merigolds control nematodes
yes- reduce them
grow w tobacco
three morphological types of protists in soil
flagellates, amoebae, ciliates
flagellates
flagella to flap around
tail
which are the smallest protists
flagellates
how do amoeba consume organisms
wrapping themselves around them
phagocytosis
ingesting orgnaic matter by wrapping them into a membrane and putting digestive enzymes into the pocket
who can do phagocytosis
eukaryotes only
two areas in which you can do your digestion
detritovores, saprotrophs
detritovores
internal digestion
earthworms, milipedes, pill bugs
saprotrophs
external digestion
all free living chemoheterotrophic bacteria
all fungi because they also have rigid cell walls
does bacteria like moist soil
yes
do fungi like moist conditions
yes but also able to thrive in dry better than bacteria (will take over)
what pH do bacterial like
neutral
can fungi survive low pH better than bacteria
yes
Do bacteria require o2
no, they will only slow down
do fungi require o2
yes
who does better in an o2 shortage bacteria or fungi
bactera
who does better in dry soil bacterial or fungi
fungi
who tolerates acidity better bacteria or fungi
fungi
who tolerates tillage better bacteria or fungi
bacteria
