Soil Fertility Management 4 ‐Nitrogen ZEF‐IPADS Joint Lecture (20 Jan. 2016) 1 IPADS Soil Fertility Management 4 NITROGEN Department of Global Agricultural Sciences IPADS Kensuke OKADA ([email protected]‐tokyo.ac.jp) ipads.jp/soil 1 (Llanos Orientales in Colombia, photo by KO) International Program in Agricultural Development Studies (IPADS) 20 January 2016 IMPORTANCE OF N IN PLANTS N of primary importance as plant nutrient 9 elements 8 elements 17 essential elements Sodium (Na), Cobalt (Co), Vanadium (Va) and Silicon (Si) (Havlin et al. 2005) Importance of N in plant (1) ‐‐‐ Protein Ribulose‐bisphosphate carboxylase Accounts for 50% of soluble leaf protein in C 3 plants (20‐ 30% of total leaf nitrogen) and 30% of soluble leaf protein in C 4 plants (5‐9% of total leaf nitrogen). (Wikipedia) Importance of N in plant (2) ‐‐‐ Nucleic acids Importance of N in plant (3) ‐‐‐ Chlorophyll N deficiency Yellow and necrotic leaves From lower leaves
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IPADS NITROGEN IMPORTANCE OF N IN PLANTSakokada/soil/files/04... · 2016-01-20 · 4 ‐Nitrogen ZEF‐IPADS Joint Lecture (20 Jan. 2016) 6 Volatilization of Ammonium Nitrate leaching
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International Program in Agricultural Development Studies (IPADS) 20 January 2016
IMPORTANCE OF N IN PLANTS
N of primary importance as plant nutrient
9 elements
8 elements
17 essential elements
Sodium (Na), Cobalt (Co), Vanadium (Va) and Silicon (Si)
(Havlin et al. 2005)Importance of N in plant (1) ‐‐‐ Protein
Ribulose‐bisphosphatecarboxylase
Accounts for 50% of soluble leaf protein in C3 plants (20‐30% of total leaf nitrogen) and 30% of soluble leaf protein in C4plants (5‐9% of total leaf nitrogen). (Wikipedia)
Importance of N in plant (2) ‐‐‐ Nucleic acids Importance of N in plant (3) ‐‐‐ Chlorophyll
N deficiency
Yellow and necrotic leavesFrom lower leaves
Soil Fertility Management 4 ‐Nitrogen
ZEF‐IPADS Joint Lecture (20 Jan. 2016)
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N FROM FERTILIZERS
N fertilizers
niter硝石nitratineチリ硝石
(Havlin et al. 2005)
Chilean nitratesHaber‐Bosch process
1909 experimental scale 1931 industrial scale
N2(g) + 3H2(g) ‐‐‐‐‐ 2NH3 (g)
Urea to ammonium
Urea hydrolysis : rapid in warm, moist soils (several days)Depending on the pH, NH3
+ volatizedUrease is abudant in the soils, especially with high OM
It is sometimes slow in cold seasons(p.152)
Soil Fertility Management 4 ‐Nitrogen
ZEF‐IPADS Joint Lecture (20 Jan. 2016)
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Slow release nitrogen fertilizers
(Havlin et al. 2005)
N CONVERSION IN SOILS
N cycle
(Havlin et al. 2005)
N input and loss
(Havlin et al. 2005)
Mineralization 1 : Aminization
Mineralization : Conversion of organic N to NH4+
by bacteria (neutral to alkaline soils)by fungi (acidic soils)
Mineralization 2 : Ammonification
Soil Fertility Management 4 ‐Nitrogen
ZEF‐IPADS Joint Lecture (20 Jan. 2016)
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C:N ratio effects on mineralization and immobilization
(Havlin et al. 2005)
C:N ratio effects on mineralization and immobilization