Nitrogen Flashcards
what do plants want from their soil
O2
watwe
Strength
Buffer pH
nutrients
6 Macronutrients
N P K Ca Mg S
Nitrogen use
protiens chlorophyll DNA RNA
Phosphorous use
DNA RNA ATP
Potassium use
Osmosis- open and close stomata
Ca use
crosslink carboxylate groups
Mg use
chlorophyll
sulfur use
amino acids- cysteine and methionine
Mobile nutrient
element that can be withdrawn from a tissue were it was originally deposited by a plant and transfered to a new tissue where it is more vitally needed at present
Transferring an element from an old leaf to a new leaf
immobile nutrients
x moved after deposition
N P K immobile or monile
mobile
what color do leaves with insufficient nitrogen turn
yellow
will yellowing leaves occur on the newest, or oldest growth
oldest - N is mobile
what are the two most important forms of N in soil
ammonium- NH4
Nitrate- NO3
ammonium in soil where is it stored
since it’s a cation, soil can store it on it’s exchange sites
what flushes ammonium off of exchange sites and therefore available to plants
rain
how do most crops obtain the N in their diets
NO3-
do clays attract NO3-
no
where can plants find NO3-
in solution
does rain flush out NO3-
yes
does the ancient N cycle of the N conversion to NH4+ still exist to raise pH
yes in conifer forests on sandy soils
since bacteria hate acid, what does the mineralization of organic N into NH4+ in the sandy coniferous low pH forests
fungi
ammonification
turning OM into ammonium
do microbes need energy to perform ammonification
not extra, they already to ammonification when they mineralize the organic carbon they took up in things like oligopeptised
They get energy from the oxidation of carbon
they end up with an excess of Nitrogen
can ammonificaiton happen without O2
yes just slower- like in archean period
Does ammonification lower pH
no it raises it. The byproduct of ammonification is one OH-/NH4+
do water molecules keep NH3 in solution
no- no net charge
it’s a water soluble gas
NH3 + H2O = NH4+ + OH-
ammonification
what will happen if you add lime to your compost
the alkaline pH will cause it to stink of ammonia
urea
most common N containing ingredient in mixed fertilizers in New England
why do manuered fields stink
it’s losing its nitrogen as ammonia
what happens if you add ammonia NH4+ ions to soil with lots of 2:1 clays
the NH4+ ions will move into exchange sites and squeeze layers together
water can’t even fit between layers
backwards weathering
how to get NH4 out of 2:1 clays
weathering
what type of bacteria figured out how to consume CO2 and produce O2
cyanobacteria
what is the aerobic nitrification equation
NH4+ + 2O2 –> NO3- + 2H+ + H2O
what does aerobic nitrogen transformation produce
energy that is captured by chemoautotrophic bacteria for growth
Does nitrification require Nitrification post photoautotrophic bacteria producitng O2?
yes- oxygen killed most others
post photo autotrophic bacteria- does nitrificaiton increase pH
no it lowers it
what do nitrifiers do
break down NH4+ to NO3-
why are nitrifiers good for plants
EXCHANGABLE nitrogen at these sites
what is the overall reaction of nitrification
NH4+ + 2O2 —–> NO3- + 2H+ + H2O
what captures the energy of oxidation and nitrification
chemoautotrophic bacteria
Does nitrification require O2
YES!!
what affect does nitrification have on pH
lowers pH creates acidity (2H+)
which is toxic to your crops and animals : nitrite or nitrate
nitrite
can complete nitrification be done by a chemoautotrophic microbe
no- must be divided by 2 chemoautotrophic nitrifiers
what two chemoautotrophic nitrifiers nitrify
ammonium oxidizers and nitrite oxidizers
what bugs create all the acidity during nitrification
ammonium oxidizers
what bugs create no acidity when nitrification
nitrite oxidizers
what are the conditions for nitrification
warm, well aerated, not too dry
do nitrifiers like the cold
no
what should you do for early spring crops
give them some nitrate
do nitrifiers like acidity
no
NH4+ oxidizers will keep working up to a pH of 9. what has caused this resilliency
they go into sites where ammonification is happening
ammonification releases NH4+ and OH-
in temperate regions- do nitrate or nitrite leach through soils of temperate regions easilt
both
TF it matters if the plant is going to take up nitrogen by ammonium or nitrate when looking at the effect on pH N assimilation will be
T- roots and microbes must stay neutral because otherwise it would repel needed nutrient ions of the same charges
To avoid developing an overall charge, what do plants do
They either take in an H+ ion for every NO3-(nitrate) they take in
or kick out an OH- for every NO3- they take in
does nitrate assimilation cause pH to increase
yes because oH is being kicked out and H+ is taken in
For the assimilation of ammonium (NH4+) what happens in plant root
OH- comes in or H+ leaves to keep charge samw
rhizosphere
all soil close enough to the root to be affected by the root
abt 5mm from root
TF rhizosphere is more affected by what form of Nitrogen the plant is assimilating
T
TF during the day the rhizosphere is moister than at night
F its drier
which is the oxidation of nitrogen
NH4+ -> NO3-
NO3- -> NH4+
NO3- -> NH4+
increasing charge
if O2 gets consumed by aerobic respiration what do the microbes do
suffocate and die
pack DNA into spores and die
ferment
find alternative oxidizer
denitrification
turning the N in nitrate into N2 gas
what happens to energy o2 and pH with denitrification
energy- provides energy
O2- anerobic provess
pH- raise pH
denitrification equation
NO3- -> NO2- -> [NO] -> N2O -> N2
in soil aggregates, where is nitrification likely to happen - outside or inside
outside where it’s moist, denitrification on the inside
at 90% filled with water pore space is nitrification going to have a high or low rate
low
it will be denitrification
nitrogen fixation
conversion of nitrogen from botanically useless N2 into ammonia NH3
ammonia gets converset to organic N in plant
plants and bugs move slower than a molecule of N2 in the air
N is fixed
do eukaryotes do biological nitrogen fixation
no only prokaryotes
biological nitrogen fixation energy o2 and ph
energy- high requirement of energy
O2- bacteria will protect the enzymes from O2. Occurs aerobically and anaerobically
pH- no effect
heterotopic bacteria who can fix N have advantage over those unable to fix N
T when carbon is abundant and N is in short supply
if there is ammonium or nitrate in a soil, what will nitrogen fixing bacteria do
stop
why do plants that excrete sugars to get a N fixators attention not work
bacteria gets to the sugars first anf also steal the ammonium as well
plants will form nodules around N fixators and never bacteria
hopefully true but not never
heghemoglobin
obygen transporting compound like hemoglobin
how are leghemoglobin used to trap rnodules
it delivers O2 to vell without allowing free o2 to diffuse int o the cell and clobber the O2- sensitive N-fixing enzymes
why should you fertilize your legumes with rhizobia instead of N
N is already avail to them its free in solution
