Nitrogen Final
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Transcript of Nitrogen Final
NITROGENNITROGEN
Nitrogen (N)Nitrogen (N)
Jaringan tanaman mengandung 1 – 5% N Diserap dalam bentuk NO3
- dan NH4+
Penyusun protein (DNA dan RNA) Bagian penting dari chlorofil (porphyrin ring
system ) Pertumbuhan vegetatif dan chlorosis Mempercepat penuaan tanaman Pembentukan karbohidrat Mudah bergerak di dalam tanah (mobile)
Nitrogen (N): 1-5%Nitrogen (N): 1-5% Gejala Defisiensi
(kekahatan)– Tanaman menjadi kerdil
dan/atau menjadi kuning pada daun yang tua
– N bersifat mobil dalam tanaman, jadi daun baru dapat tetap hijau
– Kelebihan N menghambat pemasakan, tanaman sukulen dan mudah terserang hama-penyakit
Nitrogen FertilizersNitrogen Fertilizers Natural organic materials
– guano – animal byproduct, manure, plant residues, sewage
sludge used in specialty fertilizersfor lawns and shrubs
– most of N released is converted to N in three weeks.
Natural inorganic N – Nitrate of soda (NaNO3)
mined and refined in Chile contains 16% NO3-N
– NH3 from coal (Europe)
Synthetic chemical fertilizers – Anhydrous ammonia
82% N; stored as a liquid under pressure; becomes a gas when released.
Applied directly to soil by injection tubes Some is lost to atmosphere during application. Need special equipment
– Urea [CO(NH2)2] 46% N rapid hydrolysis to NH4
+ incorporate to pervent volatilization
Synthetic chemical fertilizers – Ammonium Nitrate [NH4NO3]
33.5 -34.5 % N adsorbs moisture (hygroscopic) granulated to reduce caking can be expolsive
– Nitrogen Solutions (non-pressure) NH4NO3 and or urea urea and NH4NO3 dissolved in water called
UAN/solutions – Aqua ammonia - Ammonia gas dissolved in water
(21% N)
Synthetic chemical fertilizers– Ammonium sulfate 20.5% N
NH3 + H2SO4 =====> (NH4)2SO4
also supplies sulfate good handling and storage
– Ammonium phosphates - used primarily as a source of P
NH3 + H3PO4 =====> NH4H2PO4 ............11-48-0 Monoammonium phosphate (MAP)..... 11-48-0
– NH3 + H3PO4 =====> NH4H2PO4 Diammonium phosphate (DAP) ... 18-46-0
– (NH4)2HOP4
Synthetic chemical fertilizers– potassium nitrate .... 13-0-44
6KCl + 12 HNO3 ==> 6KNO3 + 3Cl2 + 6NO2 +
6H20
used mostly as a sidedressing
– calcium nitrate used in Europe
Symptom of Nutrients deficiency
Symptom of Nutrient Deficiency
Kekurangan Nitrogen (N)Kekurangan Nitrogen (N)
Oxidation States of Soil NOxidation States of Soil N
N Form Name Oxidation state
organic-N -3
NH4+ ammonium -3
N2 dinitrogen gas 0 (oxidation)
(reduction)
NO2- nitrite +3
NO3- nitrate +5
N-cycleN-cycleplant & animal residues
organic-N
NH4+NO2
-
NO3-
N2
11
2233
33
44
755
VolatilizationVolatilization
NitrificationNitrification
DenitrificationDenitrification FixationFixation AminasiAminasi
AmonifikasiAmonifikasi
Forms of soil NForms of soil N
1. inorganic - NO3-, NH4
+
2. organic - unavailable to plants : 97-98% of total N in soils is in the organic form. 1-2% per year is mineralized
Mineralization vs. ImmobilizationMineralization vs. Immobilization
Alfalfa, peas, grass
Low C:N (high N content)
straw, bark, sawdust
High C:N (low N)
Ammonia Volatilization Ammonia Volatilization - gaseous loss of N- gaseous loss of N
Ammonia VolatilizationAmmonia Volatilization
Urea: CO(NH2)2 NH3 +CO2 + H2O
urea soil enzymes & H2O
- Most volatilization when:coarse or sandy-textured soils
low clay and low organic matter (which adsorb NH4
+)
dry alkaline surface
– Volatilization Urea
• NH4+ fertilizers
• Anhydrous Ammonia (NH3)
NitrificationNitrificationNH4
+ NO2- NO3
- ammonium nitrite nitrate
- oxidation of N
* Autotrophic bacteria • obtain energy from N oxidation
• Nitrosomonas NH4
+ NO2- + energy
• Nitrobacter NO2
- NO3- + energy
NitrificationNitrification (cont’d) (cont’d)
* Rapid in well-aerated, warm, moist soils
• aerobic organisms (O2 is required)
• little NO2- accumulation
* Acid-forming process NH4
+ +3/2O2 NO2- + 2H+ + H2O
Nitrogen (nitrate?) Leaching
Eutrification
Denitrification
DenitrificationDenitrification
Gaseous loss of N upon N reduction
+ e- + e- + e- + e-
NO3- NO2
- NO N2O N2
nitric nitrous oxide oxide
DenitrificationDenitrification (cont’d) (cont’d)
* Microorganisms responsible:
• facultative anaerobes - prefer O2 but will use N
for a terminal e- acceptor
• mostly heterotrophic - use organic-C for energy source
(reductions require energy)
DenitrificationDenitrification (cont’d) (cont’d)
* Denitrification enhanced by:
• low O2 (flooding)
• high O.M. (energy source)
• high NO3-
DenitrificationDenitrification (cont’d) (cont’d)
* Metabolic reduction is not denitrification(no N gas formation)
NO3-
organisms
NO3- NH4
+ organic-N
- N is reduced for use in protein formation
Nitrogen FixationNitrogen FixationN2 (organisms) NH4
+
* Symbiotic relation between * Symbiotic relation between bacteria and plants:bacteria and plants:
- legumes- legumes + +
- - rhizobiumrhizobium
Bacteria: Rhizobium genus (species specific)
R. meliloti - alfalfa
R. trifolii - clover
R. phaseoli - beans
- bacteria require plant to function
- inoculation of seed
(coat seed with proper bacteria)
Nitrogen FixationNitrogen Fixation
Process:Process:
Rhizobium
nodule
(b) Process:(b) Process:
C from plant photosynthesis
N from fixation of N2 symbiosissymbiosis
RhizobiumRhizobium
organic-Corganic-C
NN22organic-Norganic-N
Quantity of N FixedQuantity of N Fixed Alfalfa and clover provide 100 - 250 kg N/ha/yr
(mature stand, good fertility & pH)
Beans and peas less fixation but high protein food
with minimum N input
added N fertilizer lowered N fixation
Symbiotic Nodules - NonlegumesSymbiotic Nodules - Nonlegumes
* Organismsactinomycetes - Frankia
* PlantsAlders and other trees
Symbiotic - without nodulesSymbiotic - without nodules
* Azolla/Anabaena complex blue-green algae (N-fixer) in leaves floating fern in rice paddies
* Rhizosphere organisms use root exudates (C)
large areas
Nonsymbiotic N-fixation:Nonsymbiotic N-fixation:Free-living OrganismsFree-living Organisms
* Bacteria and blue-green algae
aerobic and anaerobic
small amounts: 5 - 50 kg/ha/yr
inhibited by available soil N