MacroNutrients 1

MacroNutrients 1 - Macronutrients
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Unformatted text preview: Macronutrients
 Nitrogen
fixing
nodules
 h4p://blog.lib.umn.edu/denis036/thisweekinevoluAon/ 2007/08/cooperaAon_gets_complex_1.html
 ESSENTIAL
ELEMENTS
 •  We
are
learning
that
soils
 are
very
complex
medium


 •  many
reacAons
occurring


 •  the
system
as
a
whole
in
a
 constant
state
of
flux.


 Add
the
further
complicaAon
of

 •  plants,

 –  plant
uptakes
and
 –  plant
needs

 •  the
situaAon
can
become
 even
more
complex

 •  plants
all
need
slight
 differences
 •  

 generalizaAons
 •  SO
we
need
to
make
 generalizaAons
that
do
not
 fit
all
the
plants
all
of
the
 Ame

 •  
they
may
not
even
be
true
 for
any
one
plant
in
a
given
 situaAon

 Essen8al
element

 •  element
needed
for
the
 growth
and
reproducAon
of
 most
plants.

 •  FIGURE
15‐1
 Essen8al
element

 Sixteen
are
currently
accepted:


 •  •  •  •  •  •  •  •  
C



carbon














 

 
H



hydrogen











 

 
O



oxygen
 
P



phosphorus














 
 
 

 K



potassium









 

 N



nitrogen












 

 S



sulfur













 
 

 Ca


calcium













 

 •  •  •  •  •  •  •  •  Fe


iron
 Mg


magnesium
 B



boron
 Mn


manganese
 Cu


copper
 Zn


zinc
 Mo


molybdenum
 Cl


chlorine
 C,
H,
O
 macronutrients

 •  We
don't
usually
ferAlize
 with
CHO

 •  H
and
O
from
water,
and

 •  C
and
O
from
the
air,
 


 •  O
from
soil
air.


 •  Other
elements
are
also
 called
fer8lizer
elements.
 Macronutrient

 •  essenAal
element
needed
in
 large
quanAAes.


 •  
 Primary 
N,
P,
and
K
 •  MOST
FERTILIZERS
 


 •  
 Secondary 
Ca,
Mg
and
S


 Micronutrient
 •  trace
element
 •  
 Fe
needed
in
much
larger
 amounts
than
others

 •  essenAal
element
needed
in
 Any
amounts.
 •  
in
Assue
culture

it
may
be
 considered
a
macronutrient.
 •  
 Mn,
B,
Cu,
Zn,
Mo
and
Cl.
 Mobile
element
‐
plant

 N
deficiency
 •  nutrient
that
is
translocated
 to
young
growth
if
a
 deficiency
occurs.


 •  Therefore,
deficiency
 symptoms
appear
first
on
 older
growth.

 •  
N,
P,
K,
Mg,
Mo,
 

 –  possibly
S
a
li4le.


 Immobile
element
‐
plant
 Mn
deficiency
 •  nutrient
that
is
not
 translocated
to
young
 growth
in
a
deficiency
 
situaAon.

 •  Therefore,
deficiency
 symptoms
appear
first
on
 young
growth.


 •  Fe,
Ca,
B,
Zn,
 
Mn,
Cu,
Cl,
S
 to
some
extent.
 Mobile
element
‐
soil
 N
deficiency
 •  nutrient
that
is
moved
 easily
in
the
soil

 •  Can
be
lost
to
leaching
 Immobile
element
‐
soil
 P
 •  nutrient
that
is
not
in
a
form
 readily
available
for
plant
 Nutrient
balance

 •  is
just
as
important
as
the
 absolute
amount
of
any
 nutrient.

 NITROGEN


 •  Single
most
important
for
 plant
growth,

 –  acer
water
 •  especially
leaves
and
fruit


   used
for

 •  N
is
in
all
amino
acids,

 –  so
in
all
proteins,

 –  so
in
all
enzymes;

 –  also
in
nucleic
acids,
 chlorophyll
and
many
other
 compounds.


 Mobile
(in
plant
and
soil)
 corn
 •  so
foliar
symptoms
appear
 first
on
older
leaves.


 N
deficiency:
Symptoms:
 •  
 Plant
small
 N
deficiency:
Symptoms:
 •  
 Underground
parts
small,
 too
(roots,
bulbs...)
 N
deficiency:
Symptoms:
 •  Individual
leaves,
flowers,
 fruits
small
 •  
 Seeds
not
as
nutriAous
to
 us,
since
we
eat
for
protein.

 Same
for
forage.


 N
deficiency:
Symptoms:
 •  Beginning
with
the
older
 leaves,
a
uniform
chlorosis
 light
green
‐
yellow
leaves
 •  
 If
it
is
really
deficient,
plant
 may
be
too
weak
to
flower
 or
fruit
well
 Excess
N:
 •  This
is
just
as
bad
as
too
 li4le
N.

 •  
It's
common
when
 gardeners
incorporate
lots
 of
compost,
then
add
N
 ferAlizer.
 Excess
N:
 Symptoms:
 •  
 Growth
succulent,
dark
 green
succulent
vegetaAon;
 has
trouble
hardening


 •  
 

 •  
 
 Excess
N:
 Symptoms:
 Black
legume
aphid
 •  Reduced
hardiness
and
less
 insect
and
disease
 resistance.


 •  •  •  •  •  WHAT
TO
DO
–
for
…
 Plant
early
 CulAvate
clean
 Avoid
excess
use
of
nitrogen
 Conserve
natural
enemies

 •  
 
 Excess
N:
 Symptoms:
 •  Plant
tall
and
leggy
growth
 too
fast
(long
internodes),
 subject
to
lodging
 Excess
N:
 Symptoms:
 •  
River
problems
‐
e.g.
 Everglades
 •  Algal
blooms

 Excess
N:
 Symptoms:
 •  At
Lake
A(tlan
in
 Guatemala,
excess
nitrogen
 promotes
algae
growth,
 which
leads
to
 eutrophica(on.

 •  Nitrogen
is
present
in
soils
 •  •  •  •  in
organic
ma4er
 
in
amino
acids
(AAs),
 proteins,

 complex
compounds.


 THE
NITROGEN
CYCLE


 •  Nitrogen
bonds
easily
and
is
 in
many
different
forms
 •  Easily
lost
as
leaches
out
 from
soil

 DERIVED
from
the
atmosphere

 (79%
nitrogen)

 
FORMS
 •  but
not
available
to
 •  Nitrate

NO3‐
 plants
as
N2

Too
 strong
a
bond
to
break
 easily
 •  Nitrite

NO2‐
 •  so
we
need
to
“fix”
 the
N
 •  Ammonia
NH3

(gas)
 •  In
an
inorganic
form
 that
plants
can
uAlize


 •  Ammonium

NH4+
 Plants
absorb
N
as

 •  ammonium,

NH4+
 •  nitrate,
NO3‐
 •  Urea
(NH2)2CO
 –  (organic
nitrogen)
 •  nitrite
(usually
negligible).
 1)
FIXATION
(put
in
a
usable
form)


 •  Plants
mostly
absorb
NO3‐

 and
NH4+
 •  So
fixaAon
is
essenAal
for
 life
 A)
symbio8c
fixa8on

 Mainly
Legumes…
 •  They
contain
symbioAc
 bacteria
called
Rhizobia
 within
nodules
in
their
root
 systems,

 •  Producing
nitrogen
 compounds
that
help
the
 plant
to
grow
and
compete
 with
other
plants.
 Fabaceae
family
 A)
symbio8c
fixa8on

 •  
the
bacteria
have
a
 symbioAc
relaAonship
with
 the
plant


 •  
 ammonia
is
used
by
both
 for
food,
and
the
bacteria
 also
use
the
plant
for
food


 •  
 the
plant
needs
the
 nitrogen
 •  A
“gall
is
produced”


 A)
symbio8c
fixa8on

 •  
the
bacteriahave
a
 symbioAc
relaAonship
with
 the
plant


 •  
 ammonia
is
used
by
both
 for
food,

 •  and
the
bacteria
also
use
 the
plant
for
food


 •  
 the
plant
needs
the
 nitrogen


 A)
symbio8c
fixa8on

 Fabaceae
 •  Galls
are
formed

 •  nodule‐forming
N‐fixing
 bacteria,
 

 •  found
mostly
on
legumes.


 •  •  •  •  Legumes
 Soybeans
 Alfalfa
 clover
 A1)
symbio8c
fixa8on

 Non
legumes

 •  few
non‐leguminous
plants,
 such
as
alder
and
bayberry,
 that
can
also
fix
nitrogen
 •  a
symbioAc
associaAon
with
 Frankia
bacteria.

 B)
BIOLOGICAL
‐
but
non‐symbio8c
 fixa8on


 •  Independent
bacteria
–
to
 specific
plants
 •  Biological
nitrogen
fixaAon
 (BNF)

 •  atmospheric
nitrogen
is
 converted
to
ammonia
by
 an
enzyme
called
 nitrogenase
 •  They
fix
about
20
lbs./acre/ year.
 B)
BIOLOGICAL
‐
but
non‐symbio8c
 fixa8on


 •  absorb
N2
gas
(use
light,
 water,
CO2)
BY
LIVING.
 •  and
convert
it
to
ammonia
 NH3

BY
DYING
 •  REDUCING
REACTION 

 B)
BIOLOGICAL
‐
but
non‐symbio8c
 fixa8on


 •  E.g
cyanobacteria
 C)
lightening
fixa8on

 ABIOTIC
 •  high
energy
fixaAon
that
 occurs
primarily
as
lighAng
 strikes
breaks
apart
 atmospheric
nitrogen
 oxidizing
into
nitrates
 (NO3‐).
 •  
These
chemicals
dissolve
 easily
into
rain
that
is
then
 carried
down
to
the
Earth.

 Important
for
forests
 D)

industrial

 ABIOTIC
 INDUSTRY
&
FERTILIZERS
 •  Nitrogen
can
also
be
fixed
 through
man‐made
 processes,
primarily
 industrial
processes
that
 create
ammonia
and
 nitrogen‐rich
ferAlizers.

 Nitrogen
is
now
in
the
biomanss
 CYCLE
1

mineraliza8on
‐
 immobiliza8on
cycle
 mineraliza8on
 •  N
mineralizaAon
is
the
 conversion
of
organic
N
to
 mineral
forms.

 •  the
release
of
organic
 compounds
during
 decomposi8on
 .

 CYCLE
1

mineraliza8on
‐
 immobiliza8on
cycle
 mineraliza8on
 •  When
a
plant
or
animal
dies
OR
 animal
expels
waste,

 •  iniAal
form
of
nitrogen
is
sAll
 organic.

 •  Bacteria
usually
(someAmes
 fungi),

 •  Convert
organic
nitrogen
back
 into
ammonium
(NH4+),

 •  called
ammonificaAon
or
 mineralizaAon.

 .

 CYCLE
1

mineraliza8on
‐
 immobiliza8on
cycle
 mineraliza8on
 •  N
mineralizaAon
is
the
 conversion
of
organic
N
to
 mineral
forms.

 CYCLE
1

mineraliza8on
‐
 immobiliza8on
cycle
 immobiliza8on
 •  The
incorporaAon
of
soluble
 nitrogen
compounds
into
a
 plant
 –  NH4+
 –  NO3‐
 OPPOSITE…..
 CYCLE
1

mineraliza8on
‐
 immobiliza8on
cycle
 •  
some
decomposes
and
is
 •  some
reacts
with
H+
to
 released

 form
ammonium
(NH4+)

 and
absorbed
by
plants

 •  
some
to
atmosphere
–
NH3

 •  some
to
nitrificaAon
(NEXT
 CYCLE
‐
#2)
 SOME
HELD
BY
CLAY
MINERALS
 NH4+
 •  
adsorbed

 •  about
size
of
a
K+
 •  BUT
if
in
mica
or
similar
 structure
it
is
not
mobile
 any
more
 •  

 •  then
immobilized
again
by
 the
plants


 –  NH4+or
NO3
to
the
plants
 CEC

 CYCLE
2

mineraliza8on
‐
nitrifica8on
‐
 immobiliza8on
cycle

 Mineraliza8on
–
(death)
 MAYBE
CEC
 ammonium •  
This
 –  –  –  –  Absorbed
by
plants,

 adsorbed
to
clay
minerals
 Adsorbed
to

humus,

 used

by
microbes,

 – or
nitrified.


 NITRIFICATION
 NITRIFICATION
 •  NH4+
ammonium

 •  GOES
RAPIDLY
TO
nitrite
 NO2‐

 •  THEN
TO
nitrate
NO3‐


 •  NitrificaAon
‐
the
bacterial
 oxidaAon
of
ammonium
to
 nitrate;
 •  
not
in
wet
soils
as
need
O.
 •  two
groups
of
organisms
 •  1)


ammonia‐oxidizing
 bacteria
(AOB)
and
 •  2)

ammonia‐oxidizing
 archaea
(AOA)
 1)


ammonia‐oxidizing
bacteria
 (AOB)

 2)

ammonia‐oxidizing
archaea
 (AOA)
 •  Rare
bacteria

 •  oxidizes
ammonia
into
 nitrite
as
a
metabolic
 process.

 •  oxidizing
nitrite
into
nitrate
 in
soil.
 •  Nitrosomonas
is
a
genus
 comprising
rod
shaped
 chemoautotrophic
bacteria.
 •  Nitrobacter
is
genus
of
 mostly
rod‐shaped
 chemoautotrophic
bacteria
 •  Favored
by
warm,
slightly
 acid,
aerobic
moist
soil.


 •  Nitrobacter
have
an
 opAmum
pH
between
7.3
 and
7.5,
 •  will
die
in
temperatures
 exceeding
120°F
(49°C)
or
 below
32°F
(0°C)
 •  The
first
reacAon
releases


H+

 •  Makes
soil
more
acidic
 •  may
need
to
lime
to
 counteract
this.
 •  2
NH4+

+

3
O2







 Nitrosomonas


(bacteria)
 FORMS
 



2
NO2‐

+

2
H2O

+

4
H+
+
 energy
 •  2
NO2‐

+

O2







 Nitrobacter
(bacteria)
 •  Oxidizes
nitrite
to
nitrate
 FORMS
 






2
NO3‐
+
energy
 •  Plants
use
the
nitrate
‐
 IMMOBILIZATION


 •  REACTIONS
–
both
need
 oxygen
 •  nitrates
are
soluble
and
 move
easily
in
water

 •  used
easily
by
plants


 •  BUT
if
using
ferAlizer
need
it
 more
than
once
as
moves
to
 the
plant
so
easily


 CYCLE
3
‐
DENITRIFICATION
‐
 atmosphere
‐
fixa8on
cycle


 •  results
in
the
loss
of
N
to
 the
atmosphere
by
 microbial
acAvity


 •  N2O

N2
 •  Denitrifica8on

 •  NO3−
→
NO2−
→
NO
+
N2O
 →
N2
(g)
 •  microbially
facilitated
 process
of
nitrate
reducAon

 •  may
ulAmately
produce
 molecular
nitrogen
(N2)
 •  through
a
series
of
 intermediate
gaseous
 nitrogen
oxide
products.

 •  The
process
is
performed
 primarily
by
heterotrophic
 bacteria
 •  They
live
deep
in
soil
and
in
 aquaAc
sediments
where
 condiAons
are
anaerobic.
 •  
They
use
nitrates
as
an
 alternaAve
to
oxygen
for
the
 final
electron
acceptor
in
their
 respiraAon
 •  They
close
the
nitrogen
 cycle.

 anaerobic
condiAons
 •  biochemical
reducAon
of
 nitrates
under
anaerobic
 condiAons
in
water
or
acer
 a
rain.
 
The
cycle


 CROPPING
‐
USES
AND
PROBLEMS
‐
 fer8lizers


 •  Agriculture
may
now
be
 responsible
for
one‐half
of
 the
nitrogen
fixaAon
on
 earth
through

 •  the
use
of
ferAlizers
 produced
by
industrial
 fixaAon

 •  the
growing
of
legumes
like
 soybeans
and
alfalfa.
 •  IN
the
winter
plants
have
 li4le
use
for
nitrogen


 •  if
nitrates
are
present
they
 leach
from
the
soil
and
can
 be
a
problem
for
 groundwater
recharge


 •  BEST
‐
to
use
ammonium
in
 the
FALL
‐
+ve
charge
‐
CEC
‐
 does
not
get
leached


 •  N
‐
FERTILIZERS
‐
required
 especially
for
high‐yielding
 crops
e.g
corn


 •  

 •  an
excepAon
to
this
may
be
 legumes
‐
soybeans,
clover,
 alfalfa
may
get
all
their
 needs
by
nitrogen‐fixing
and
 galls
produced
by
bacteria.


 •  If
we
add
residue
to
the
soil
 ‐
plough
it
in
we
get
N
 added


 •  BUT
if
all
the
crop
is
 harvested
we
get
a
net
loss
 of
N
‐
need
to
ferAlize


 •  Some
plant
residue
be4er
 than
none.


 PHOSPHORUS


 macronutrient
 •  Needed
in
large
amounts
 •  Used
for
:

 –  nucleic
acids
(geneAc
info),
 –  phospholipids
(membranes),

 –  ATP
et
al
(energy
currency,
 very
important
for
converAng
 sugars
to
starches),

 –  cell
formaAon,

 –  root
and
 

 –  reproducAve
growth

 •  CRUST
has
0.1%
P
‐

really
 plenty
for
plant
growth
BUT
 it
is
rela8vely
insoluble
 –  A
problem
 •  
 Most
as
apaAte
(mineral)
–
 in
igneous
rocks
‐
 weathering
‐
soil

 •  "Blossom
Booster"
ferts
are
 high
in
P”.


 •  Mobile
in
the
PLANT.
 –  Old
leaves
(grape
below)

 •  Immobile
in
the
SOIL
 Deficiency
symptoms:
 •  
 Purpling
of
leaf
veins,
 peAoles,
margins,
and
 stems.
 •  
 If
yields
are
reduced
 without
classic
purpling,
 called
hidden
hunger.


 Deficiency
symptoms:
 •  
 StunAng,
with
short
spindly
 internodes.


 •  
 Li4le
branching.


 •  
 Few
flowers
and
fruits,
so
 also
poor
seed
producAon.



 Roots
of
papaya 
 
normal
‐
deficient
 High
phosphorus
levels
in
water
allow
 excess
growth
of
aquaAc
plants
 •  Major
role
in
plants
is
in
the
 transfer
of
energy
between
 compounds
in
various
 metabolic
cycles

 •  In
humans
(mammals)
 –  
bones
+
teeth
 –  DNA


 Immobile
in
the
SOIL

 so
how
do
we
ferAlize?


 Li`le
is
lost
by
leaching;
 most
is
lost
by
soil
erosion,
 so
P
is
usually
low
in
highly
 weathered
soils.


 •  Eroding
soil
with
P
Aghtly
 a4ached
is
a
major
source
 of
phosphate
polluAon
of
 water.


 •  •  •  •  •  GOOD
–
lose
li4le
by
 leaching
 •  BAD
–
not
available
 •  Most
is
FluorapaAte


 –  eqn.
Ca10(PO4)5F2


 •  has
fluorine
which
resists
 decay
‐like
our
teeth


 •  weathers
to
orhophosphoric
 acid

H3PO4
























 •  
or

H2
PO4

‐orthophsphate
 


 •  +
many
compounds
with
Al,
 Ca,
Fe
etc


 •  however
H2PO4‐
reacts
with
 other
ions
in
the
soil
easily


 •  precipitaAon
/
adsorpAon

 of
P
compounds


 •  FIXED
‐
unavailable


 •  AGAIN
‐
IMMOBILIZED
to
 plants
‐
organic
P
‐
20‐30%
 of
P


 •  mineralized
by
 microorganisms


 DIAGRAM
14‐1
 •  insolubility
related
to
pH
 lets
look
at
P
as
our
e.g
of
 this


 diag
14.2


 •  In
calcite
‐
rich
soils
‐
basic
 soils
‐

Ca
rich
P
compounds
 are
stable
and
insoluble
‐
so
 soils
lack
P
that
is
available
 to
plants
if
in
this
form


 •  Middle
soils
‐


 •  acidic
soil
‐
P
compounds
 with
Al
and
Fe
‐
they
are
 insoluble
and
stable


 •  a
li4le
li4le
is
returned


 •  even
if
we
add
say
a
Ca‐P
 compound
to
an
acid
soil
 the
P
will
quickly
react
with
 the
Fe
and
Al
to
form
fixed
 compounds.


 •  Best
for
all
solubiliAes
at
pH
 6‐7
(discounAng
 flourapaAte)
BEST
at
pH
6.5


 •  can
exceed
95%
of
P
in
acid
 and
basic
soils
“fixed”


 •  Good
news
‐
bad
news


 •  

 •  SO
‐
very
li4le
P
is
available
 BUT
li4le
leached
too!!!


 •  OPPOSITE
TO
NITRATES
?
 NITRITES


 •  with
Ame
the
amorphous
 Ca
Fe
Al
P
compounds
 become
more
Xlline
‐
and
 even
less
available


 •  LITTLE
P
gets
to
plants
via
 water
flow
as
such
low
 solubility


 •  diffusion
is
the
main
 process.


 Potassium
‐
K
 •  Mobile
in
plant

 •  Mobile
in
soils
 •  Available
–
2.6%
crust
 •  Mica
 •  Feldspars
–
weathering
 produces
K+
 •  Held
CEC
 •  OsmoAc
and
ionic
 regulaAon
 K
deficiency
 K
deficiency
 Sulfur
cycle
 •  Cycle
similar
to
N
 •  Used
in
some
AAs
(so
in
 many
proteins),

 •  Fairly
immobile
in
plant
 •  enzyme
acAvaAon,
 •  vitamins,

 •  
Organic
S
must
be
mineralized
 •  needed
for
chlorophyll
 before
available;
 formaAon
 •  
requires
bacteria
 •  protein
movement,

 •  favored
by
aerobic
soil,
 •  N
fixaAon.
 nearness
to
roots
since
 >microbes.
 S
‐
deficiencies
 Leaves
uniformly
pale
yellow
then
beige
 (usually
young
leaves)







 StunAng
of
the
new
growth
 Atmospheric
sulfur
 •  PROBLEM
–
acid
rain
 •  Sulfuric
acid
 ...
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This note was uploaded on 01/23/2012 for the course GEOL 306 taught by Professor Staff during the Spring '08 term at George Mason.

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