Nitrogen Final

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NITROGEN NITROGEN

description

mkt nitrogen

Transcript of Nitrogen Final

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NITROGENNITROGEN

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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)

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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

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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)

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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

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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)

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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

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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

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Symptom of Nutrients deficiency

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Symptom of Nutrient Deficiency

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Kekurangan Nitrogen (N)Kekurangan Nitrogen (N)

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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

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N-cycleN-cycleplant & animal residues

organic-N

NH4+NO2

-

NO3-

N2

11

2233

33

44

755

VolatilizationVolatilization

NitrificationNitrification

DenitrificationDenitrification FixationFixation AminasiAminasi

AmonifikasiAmonifikasi

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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

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Mineralization vs. ImmobilizationMineralization vs. Immobilization

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Alfalfa, peas, grass

Low C:N (high N content)

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straw, bark, sawdust

High C:N (low N)

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Ammonia Volatilization Ammonia Volatilization - gaseous loss of N- gaseous loss of N

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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

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– Volatilization Urea

• NH4+ fertilizers

• Anhydrous Ammonia (NH3)

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NitrificationNitrificationNH4

+ NO2- NO3

- ammonium nitrite nitrate

- oxidation of N

* Autotrophic bacteria • obtain energy from N oxidation

• Nitrosomonas NH4

+ NO2- + energy

• Nitrobacter NO2

- NO3- + energy

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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

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Nitrogen (nitrate?) Leaching

Eutrification

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Denitrification

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DenitrificationDenitrification

Gaseous loss of N upon N reduction

+ e- + e- + e- + e-

NO3- NO2

- NO N2O N2

nitric nitrous oxide oxide

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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)

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DenitrificationDenitrification (cont’d) (cont’d)

* Denitrification enhanced by:

• low O2 (flooding)

• high O.M. (energy source)

• high NO3-

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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

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Nitrogen FixationNitrogen FixationN2 (organisms) NH4

+

* Symbiotic relation between * Symbiotic relation between bacteria and plants:bacteria and plants:

- legumes- legumes + +

- - rhizobiumrhizobium

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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

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Process:Process:

Rhizobium

nodule

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(b) Process:(b) Process:

C from plant photosynthesis

N from fixation of N2 symbiosissymbiosis

RhizobiumRhizobium

organic-Corganic-C

NN22organic-Norganic-N

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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

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Symbiotic Nodules - NonlegumesSymbiotic Nodules - Nonlegumes

* Organismsactinomycetes - Frankia

* PlantsAlders and other trees

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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

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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