Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
1
ZEF‐IPADS Soil Fertility Management ‐6‐
Plant Nutrient Acquisition (1)
Department of Global Agricultural Sciences , IPADS
Kensuke OKADA
([email protected]‐tokyo.ac.jp)
1
International Program in Agricultural Development Studies (IPADS) 21 January 2016
Today’s topic
1. Phosphorus acquisition
2. Aluminum tolerance
3. Tolerance to iron deficiency
4. Biological nitrification inhibition
5. Organic N utilization
1. PHOSPHORUS ACQUISITION
Pigeonpea cultivation in the worldhttp://gisweb.ciat.cgiar.org/GapAnalysis/?p=1205
Pigeon pea (Cajanus cajan (L.) Millsp)
Origin : India (at least 3,500 yrs ago)Today cultivated in India, east Africa and Central AmericaShrub to grow for a few years (long‐duration), medium, short (3‐4 months).Usually inter‐croped with sorghum, pearl millet or maize.
Forms of P in soil
(Otani et al. 2001)
(Stevenson 1994)
Specific Organic P Compounds
Sorghum
Chickpea
Pigeonpea
Grain yield (t/ha)
Sorghum
Grain yield (t/ha)
Pigeonpea
Chickpea
P
P applied (kg P / ha)
Response of sorghum, pigenopea, and chickpea to P application in a Vertisol and an Alfisolfield of low P fertility
Shoot dry weight of plant species without P application on P deficient soils(Grain filling stage, pot exp. )
0
1
2
3
4
5
6
7
乾物重
(g
)
ソルガム キマメ ダイズ トウジンビエ トウモロコシ
Alfisols
Vertisols
Pigeonpea could grow better on Alfisol compared with other crops.
Sorghum Pigeon Soy Pearl Maizepea bean Millet
(Ae et al. 1990, Science 248,477‐480)
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Growth of sorghum and pigeonpea on Vertisol and Alfisol without P application
Pigeon pea(Cajanus cajan (L.) Millsp.)
Sorghum(Sorghum bicolor (L.) Moench)
Vertisol Alfisol Vertisol Alfisol
• Hypothesis for the better growth of pigeonpea in low‐P soil1. Pigeonpea can utilize large volume of soil by its extensive root system2. Association with VAM3. Special mechanism of pigeonpea
Hypothesis 1 : Pigeonpea can utilize large volume of soil by its extensive root system
×REJECTED
(Ae et al. 1990, Science 248,477‐480)
(Okada)
Hypothesis 2 : VAM association as mechanism to acquire P ×REJECTED
(Ae et al. 1990, Science 248,477‐480)
Forms of P in Alfisol and Vertisol
(Ae et al. 1990, Science 248,477‐480)
When Fe‐P (FePO4) was applied as only source of P (the lowest figure), pigeonpea absorbed more P than other crops
→Pigeonpea has the special ability to absorb Fe‐P which other crops cannot utilize
(Ae et al. 1990, Science 248,477‐480)
The amount of the ordinary organic acids exuded from the roots of pegeonpea and other crops
→Pigeonpea is not different from other crops
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Soybean Sorghum Pigeonpea
Pigeonpea had unique peak that other crops did not have (GC)
(Ae et al. 1990, Science 248,477‐480)
Active substance in the root exudates of pigeonpea which is responsible for Fe‐P solubilization (identified by GC‐MAS)
p‐Hydroxybenzoic acid Tartaric acidPis=fishcidic=toxicJamaica dogwood
(Ae et al. 1990, Science 248,477‐480)
Piscidic acid
Root Alfisol
Exclusion from rhizosphere
A mechanism of P solubilization by pigeonpea (hypothesis)
Uptake
Grainyield(t/ha)
P applied for sorghum (kg P / ha)
2nd year (P‐S)
3rd year (S‐P‐S)
1st year (S)
Effect of pigeonpea on the following sorghum in low‐P alfisols.
Effect of different crops on the following growth of maize in low‐P Alfisols (no P added)
After intercropping ofsorghum andpigeonpea
After pigeonpea
Aftersorghum
(Ae)
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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SoleSorghum
SolePigeonpea
Sorghum/PigeonpeaIntercropping
Amountof Pabsorbedby plant(kg P/ ha)
P absorbed bysorghum
P absorbed bypigeonpea
Effect of sorghum/pigeonpea intercropping on theP uptake from low‐P Alfisol (Ae)
P applied (kg‐P/ha)
Strategy to acquire P from Ca‐P
<Chickpea>
Sorghum
Pigeonpea
Chickpea
Grain yield (t/ha)
P forms in Alfisols and Vertisols
When pH decreases, phosphorus is solubilized in
Vertisols and Ca‐P
Chickpea acidifies its rhizosphere by exuding citric acid from the roots
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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When P is held by Fe and Al on the surface of clay
In the case of organic P
(Otani et al 2001)
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Organic acid exudation from roots and solubilization of P in a volcanic ash soil and absorption mechanism
Citrate exudation from proteoid roots in Lupin
Proteoid roots in Lupinus albus
→Proteoid roots increases under P deficient conditions
Organic acid secretion induced by P deficiency in crop species
(Randall et al. 2001)
Estimated available P for different cropsExudation of organic acids from different parts
of plant roots
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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P acquisition mechanisms : Synthesis(Randall 2001)
P deficiency was overcome by the introduction of Pup1 loci (P uptake 1)
Nipponbare
NIL-Pup1Nipponbare introduced with Pup1
Kasalath
Near isogenic line with Pup1 loci (NIL-Pup1): 97% same as ‘Nipponbare’ but Pup1 (on 12th chromosome) from Kasalath
(indica varitey) was introduced →Introduction to NERICA
Genetic Improvement B(Low soil fertility, contd.)
(Wissuwa, 2009)
2. ALUMINUM TOLERANCE
Malic acid secretion as a resistant mechanism to Al in wheat
(Delhaize et al 1993)
Malic acid in wheat
(Delhaize et al 1993)
Malic acid secretion as a resistant mechanisms to Al in wheat
(Delhaize et al 1993)
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Citric acid for maize
Citric acid in maize
• Citric acid secretion from root apex is playing important role in Al resistance, not the secretion of the entire roots.
Oxalic acid in buck wheat(buck wheat is for SOBA noodle and crepes)
(Ma et al 1997)
Summary organic acids secretion as the mechanism of Al resistant
• Malic acid : wheat• Citric acid : maize, Cassia tora
• Oxalic acid: Buckwheat
3. IRON DEFICIENCY TOLERANCE
Iron Deficient Rice in calcareous soil (Vertisol)Photo by Prof. Naoko Nishizawa
Forms of Fe in soils
1. Fe2+ ←‐‐‐‐‐→ Fe3+
Reduced form Oxidized form
Water soluble Water insoluble
Grey/Blue Red
2. Deficiency symptom : Chlorosis in younger leaves
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Fe deficiency symptom
(Matsunaka2003)
Maize plants in solution culture
The interveinal symptoms look like Mg deficienty, but the chlorosis of Mg deficiency starts from the lower leaves. (The topic of phytosiderophore (iron‐chelating compound) will be discussed in another lecture (Plant Nutrient Acquisition)).
Inquiry on the yellowing of the leaves of upland rice (NERICA) in the northern part
of Benin, Africa
44
•Depending on the varieties•Soil pH=7.6‐8.2•Yellowing of upper leaves
•Not N deficiency
Which problem ?
Iron deficiency
Iron (Fe) acquisition:Strategy I (dicotyledonous crops)
(Mori 2001)
Animationhttp://www.winep.jp/feuptake.html
Iron acquisition strategy II(monocots)
Role of mugineicacid to chelate Fe3+
to absorb from soil and transport in plant body
(Mori 2001)
Animationhttp://www.winep.jp/feuptake.html
Mugineic acid – How was it found?
Classis experiment by Prof. S. Takagi (Tohoku Univ.)• Rice was grown with synthetic soil (sand+ clay, without organic matter) under both upland and irrigated conditions.
• On this soil, rice in upland conditions grew well in wide pH conditions including higher pH range, while that in irrigated condition it suffered from chlorosis (Fe deficiency) at pH>6.0. (These are the unexpected results)
• Takagi intuited that the rice roots excrete a chelator‐like iron‐solubilizing substance, but the substance might be leached from the rhizosphere under flooding conditions.
• In the flooded conditions of normal soil, the rice plants do not suffer from iron deficiency, because the soil is in reduced conditions, and most of the iron exists in Fe2+ form which is soluble and can be easily absorbed by plants. But in the synthetic soil, this did not happen.
Mugineic acid
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Mugineic acid
• Takagi later identified a chelating substance for iron which is produced from rice roots under iron deficiency, which was later identified as mugineicacid (MA).
• It was found afterwards that MA was excreted from the roots of various crops (cereals), too.
• In fact, there is a good correlation between the degree of Fe efficiency of major cereal crops and the ability of their roots to liberate mugineic acid under Fe deficienc: barley>wheat, rye>oats>maize>sorghum>rice.
• The MAs production system has come to be called Strategy II for graminaceous crops.
Lowland rice in inland‐valley, and upland in the slopes(Cote d’Ivoire, West Africa)
Iron toxicity
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4. BIOLOGICAL NITRIFICATION INHIBITION (BNI)
(a). The mechanisms of nitrification suppression and inhibition of nitrous oxide emission by Brachiaria humidicola
Common nitrification inhibitor
• N‐Serve (nitrapyrin)
• DCD (dicyandiamide)
• DMPP (3,4‐dimethyl pyrazole phosphate)
Effect of crops on the number of the ammonia oxidizing bacteria
Brachiaria decumbens
Melinis minutiflora
Brachiaria humidicola
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Effect of crops on the following nitrification processes in the soils
(Subbarao et al. 2012)
(Subbarao et al. 2012)
(Subbarao et al. 2012) (Subbarao et al. 2012)
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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5. UTILIZATION ORGANIC NITROGEN BY PLANTS
Organic vs. Inorganic Nutrition Theory
• Thaer, A. D. (1752‐1828)“Humus (organic matter) of the soils is the nutrients for plants.”
• von Liebig, J., (1803‐1873)“CO2 and ammonia from air, and H2O, P, S, Si, Ca, Mg, K, Na, Fe, NaCl from soil are the important nutrients for plants.”
“Manure are not utilized by plants directly, only after decomposition.”
“Plants can grow only with inorganic nutrients”
Latitude and net N mineralization rate
(Kielland 2001)
Boreal forest (Taiga)
Proposed new nitrogen pathway=Short‐Circuiting
UPTAKE
(Kielland 2001)
Forms of N in cold climate(Kielland 2001) N utilization by
arctic plants
• Arctic sedge utilize more N from amino acids while barley uses more inorganic nitrogen
(Kielland 2001)
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
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Species difference in the preference to glycine over ammonium
(Kielland 2001)
Contrasting N uptake among crops from organic and inorganic N sources
(Yamagata et al 2001)
Forms of nitrogenous compound in the soils under different climates
(Sowden et al. 1977)
Forms of nitrogen in the soils in the world• Proteneiceous N compounds
(protein, peptide, amino acids) 40%• Free amino acids 5‐6%• Heterocyclic N coumpouds 35%• NH3 19%
(Shulten and Schnitzer 1998)
Different effects of organic and inorganic N sources on vegetables
(Yamagata et al 2001)
Experiment in aseptic conditionsChingensai Carrot Pimento
20% 10% ControlSoil Extract
(Matsumoto et al 2000)
Xylem sap composition in two vegetables contrasting in
the utilization of organic and inorganic nitrogen
(Matsumoto et al 2000
Soil Fertility Management ‐6‐ Plant Nutrient Acquisition
ZEF‐IPADS Joint Lecture (18‐22 Jan. 2016)
13
Effect of organic and inorganic N on sorghum growth on volcanic ash soil (Tsukuba, Japan)
Organic N(Rice bran+strawC/N=20, 150kgN/ha)
Inorganic N(Urea, 150kgN/ha)
Inorganic NWithout NOrganic N
The growth of sorghum on volcanic ash soil in Japan applied with 150 kg/ha N in inorganic (ammonium sulfate) or organic forms (rice bran and straw, C/N=20) (Okamoto et al. 2003)
A
B
C
D
A
B
C
DAS
73
86
108
DAS
73
86
108
128
ON IN
ON IN
Sorghum
Pearl millet
(Tsukuba, Japan)150 kgN/ha IN=Urea, ON=Rice bran+straw
(Okamoto et al. 2003)
AN : ammonium nitrateBran : rice bran (C/N=12)Bran+Straw (mixture of rice bran and straw, C/N=20)
0
2
4
6
8
10
12
14
Control AN Bran Bran+Straw
N吸
収量
(m
g pl
ant-1
)
a
bc
b
c
0
2
4
6
8
10
12
14
Control AN Bran Bran+Straw
a
bc
ac
b
Rice Sorghum
N u
pta
ke (
mg
/pla
nt)
0
5
10
15
20
25
30
35
40
45
50
Control AN Bran Bran+Straw
a
b
c
a
0
5
10
15
20
25
30
35
40
45
50
Control AN Bran Bran+Straw
a
b
c
a
Pearlmillet
Maize
N u
pta
ke (
mg
/pla
nt)
Pearl millet, maize pattern[NH4NO3]>[Bran]>[Bran+Straw]≧[No N]
Sorghum, rice pattern[Bran+Straw]≒[Bran]≒[NH4NO3]>[No N]
Effect of organic and inorganic N application on the nitrogen uptake of four gramineous crops (pot experiment).
Pearl millet →Inorganic N Sorghum→Organic N
(Okamoto andOkada 2004)
Ability to absorb proteinaceous N by gramineous crops
N u
pta
ke r
ate
(µ
mo
l g–1
roo
t D.W
. 3 h
–1)
P rotein N
Nitrate N
Am m onium N
-5
0
5
10
15
Sor
ghum
Ric
e
Mai
ze
Pe
arl
mill
et
N uptake rates of the four crop species when N was applied to the root bathing solution in the form of proteinaceous N extracted from soils in agricultural field. (Extracted organic N was dialized to exclude molecules <3,500Da)
(Okamoto and Okada 2004)