Basu Dev Regmi.ppt - The UWA Institute of Agriculture ...€¦ · Basu Dev Regmi School of Earth...

Basu Dev RegmiSchool of Earth and Environment

Basu was born and raised in the rural mountains of Nepal. He did undergraduate (B Sc Ag) degree from TribhuvanHe did undergraduate (B Sc. Ag) degree from Tribhuvan University, and M. Sc. (Agri. Systems) at Asian Institute of Technology, Bangkok, Thailand. Basu worked with agricultural research and development in Thailand and g pNepal. He worked with the bilateral project funded by Swiss government and implemented by the Nepalese government for 5 and half years as theme leader of “soil fertility and plant nutrition” discipline before joining UWA. Having motivated to work in rural communities, he has seen and experienced the different dimensions of problems in these communities His PhD research aims atproblems in these communities. His PhD research aims at investigating the dynamics of zinc (Zn) in biological and conventional farming systems, in WA. How best we can load the Zn into edible parts of the crops is the main

The UWA Institute of

Agriculture

interest of work.

D i f i l i i hDynamics of zinc accumulation in wheat grains grown in the soils of conventionalgrains grown in the soils of conventional

and biological farming systems

Basu Dev Regmi

School of Earth and EnvironmentSoil Science and Plant Nutrition

Supervisors:W/Prof Zed Rengel and


Agriculture

Dr Hossein Khabaz-Saberi

Content

1. BackgroundgRole of Zn in plant Zinc in soil and its trendGlobal scenario of Zn (impact on human…..) and role of Australiaof AustraliaZinc with respect to farming practice

2 Method and Materials2. Method and Materials3. Results 4. Conclusion


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Role of Zn in plant• Stimulate germination in low Zn soils• Involves many cellular process (enzyme• Involves many cellular process (enzyme

activation....)• production of auxin an essential growth hormone• production of auxin, an essential growth hormone • regulates starch formation and proper root

developmentdevelopment • biosynthesis of chlorophyll and carbohydrates • enable plants to withstand lower air temperaturesenable plants to withstand lower air temperatures • helps in the biosynthesis of cytochrome; a pigment,

and maintains plasma membrane integrity, andand maintains plasma membrane integrity, and synthesis of leaf cuticle.............


AgricultureCont Background

Effects of zinc deficiency on metabolic processes associated with growth

Source: Mac Donald, 2000.



Zn in soils• Among micronutrients in soil, low Zn availability is most widespread

Cereals growing areas are particularly affected by low Zn• Cereals growing areas are particularly affected by low Zn (Cakmak et al, 1998, Singh et al 2005)

• Among cereals, wheat is the most sensitive to Zn deficiency (Cakmak et alAmong cereals, wheat is the most sensitive to Zn deficiency (Cakmak et al, 1998, Kabata-Pendias, 2001, Alvarez and Gonzalez, 2006)

• Post green revolution: increased crop production with increased use of i l f ilimineral fertilizers

• Increased use of mineral fertilizers led to higher production hence d l t d i h t il f tilit ( t i t i i )depleted inherent soil fertility (nutrient mining)

• Mostly macro-elements are taken into consideration (N P K)

• Imbalance among plant nutrients ……………………..



• 5th out of 10 Risk Factors in De eloping

Zinc affects a Zinc affects a Factors in Developing Countries to Cause of

range ofrange of functions:functions:

• ImmunityDisease Burden (WHO, 2002)

• About 3 billion people • Growth• Brain development • Reproductionbout 3 b o peop e

are affected by low Zn (Stein et al 2007)

p• Sexual Formation

( )

• Over 1 million child death due to Zn with Vitamin Adue to Zn with Vitamin A (The Lancet Maternal and Child Undernutrition Series January 2008)


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y )

Current concentration of Zn in cereal grains 10 30 /k10-30 mg/kg

Required concentration of Zn

PhytatePhenolic compounds ……..

concentration of Zn in cereal grains40-60 mg/kg for humanhuman consumption

Increasing micronutrient density in edible parts of plant—highly desirablehighly desirable


AgricultureZn ++ Cont Background

Zn Deficiency: Global Nutritional Problem in Soils

Widespread Zn DeficiencyWidespread Zn Deficiency

Medium Zn Deficiency

Alloway, 2004. IZA Publications, Brussels


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y, ,

Cont Background

Countries at Risk of Zinc Deficiency in Children


AgricultureBlack et al. 2008 The Lancet Maternal and Child Undernutrition Series

Market destination of Australian bulk wheat exports (- 13 million t)


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www.wea.gov.au

Cont Background

• Increasing on the awareness on soil health, environment, …………..

• Organic farming and product are preferred

• Biological farming systems are not organic farming systemsBiological farming systems are not organic farming systems

• Biological farming systems (BF) is combination of orgainc and conventional which aims to achieve optimum yield byconventional, which aims to achieve optimum yield by balanced use of organic and mineral fertilizers.

• Conventional farming system (CF) aims to achieve highestConventional farming system (CF) aims to achieve highest possible yield through the use of mineral fertilizers and other external inputs.

• How farming practices impact the nutritional quality of grains, in particular grain Zn density?



Aims• Characterize the distribution

f Z f ti f il ( tof Zn fractions of soils ( two farming systems)

• Characterize the concentration and content ofconcentration and content of Zn in shoot and seed of wheat grown in two soils


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grown in two soils

2. Method and Materials

Identification of appropriate sites:Identification of appropriate sites:- with history of conventional or biological farmingfarming- the same soil type, adjacent paddocks

We identified Dalwallinu as an appropriate siteWe identified Dalwallinu as an appropriate site for soil collection :

Biological paddock:Biological paddock:• 30 ° 14‘ 203" S, 116° 31‘ 299" E

Conventional paddock:The UWA Institute of

Agriculture

Conventional paddock:• 30 °14‘ 210" S, 116° 32‘ 339" E

History of biologically and conventionally managed soils in Dalwallinu

Farming Crop rotationgsystems

p

2001 2002 2003 2004 2005 2006 2007 2008 2009

Biological Clover Brown Manure

Wheat

Wheat Green Wheat Wheat Green wheatManure at Manure Manure

C i l Wh t Wh t Wh Wh Wh Wh O h WhConventional Wheat Wheat Wheat

Wheat Wheat Wheat Oats Wheat Wheat

Source: Rob Harris, farmer, Dalwallinu


AgricultureCont Method and Materials

Cont Method and Materials

Soil Properties 2008

O (C C ) ( )

2003( )

SitepH –H2O (CaCl2) 4.9 (5.7)

OM (%) 0.9

NO3 –N (mg/kg) 9.5

NH N (mg/kg) 2

Soil Properties 2008

pH –H2O (CaCl2) 5.1 (5.4)

OM (%) 0 96

20036.00 (5.44)

5.5 (5.9)1.14

5

• Dalwallinu (Lat. 30° 14'166" S and NH4-N (mg/kg) 2

Phosphorous (mg/g) 18

Potassium (mg/g) 42

DTPA Zn (mg/kg) 0 36

OM (%) 0.96

NO3 –N (mg/kg) 13

NH4-N (mg/kg) 2

Phosphorous (mg/g) 22

0.9574

21

11742

Long. 116 °32' 377" E) DTPA Zn (mg/kg) 0.36

Total Zn (mg/kg) 10Phosphorous (mg/g) 22

Potassium (mg/g) 60

DTPA Zn (mg/kg) 0.62

Total Zn (mg/kg) 12 5

2156

0.56

0.40

• Merredin (Lat. 31° 44' 530" S and Long. 118° 18' 879" E)

Total Zn (mg/kg) 12.5

118° 18' 879" E),

Biological paddock


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1 Characterization of soil Zn:1. Characterization of soil Zn:

• Sequential fractionation as outlined by Iwasaki and Yoshikawa (1990, 1993).Iwasaki and Yoshikawa (1990, 1993).

• Total Zinc by aqua-regia• DTPA - extractable Zn



F ti Chemicals/methods

Sequential fractionations methodsFraction Chemicals/methods

1 Water soluble (WS) 1.5gm soils in 25mL MQ water shaken for 16 hours

2 Exchangeable (EX) Wash with 10mL of MQ water and 25 mL of 0.5 M Calcium Nitrate Ca(NO3)2. 4H2O for 16 hours

3Specifically adsorbed (SA) Wash with 10mL of MQ water and

25 mL of 0.05M Lead Nitrate Pb(NO3)2

0.5 M Ammonium Acetate (CH3COONH4) for 2 hours

Acid soluble (AS) Wash with 10mL of MQ water and 4 Acid soluble (AS) 25 mL of 25mL Acetic Acid CH3COOH/LMQ water for 2

hours

5Manganese (Mn)-oxide-occluded (Mn-OX) Wash with 10mL of MQ water and

50 mL of 0.1 M Hydroxylamine Hydrochloride NH2OH.HCl for 30 min

6 Organic matter occluded (OM) Wash with 10mL of MQ water and 50 mL of 0.1 M Potassium pyrophosphate K4 P2O7 for 2 hours

amorphous iron (Fe)-oxide-bound (AFe-OX) Wash with 10mL of MQ water and

7amorphous iron (Fe) oxide bound (AFe OX) 50 mL of 0.1M Oxalic acid (COOH)2. 2H2O

and 0.157M Ammonium Oxalate (NH4)2C2O4 for 4 hours

8

crystalline Fe-oxide-bound (CFe-OX) Wash with 10mL of MQ water and 50 mL of ( 0.1 M Oxalic acid (COOH)2. 2H2O , 0.175M Ammonium Oxalate (NH ) C O 0 1 M Ascorbic acid C H O8 Ammonium Oxalate (NH4)2C2O4 0.1 M Ascorbic acid C6H8O6

for 30 min boiling bath

9 Residual (RES) Total Zinc – Sum of all fractions (as Alvaraz, et.al.,2006)

A i


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10 Total (TZn) Aqua-regia

2. Glasshouse experiment on Zn loading into wheat grains:

• Soils : Biological and Conventional Farming Systems

• Genotypes: Excalibur (Zn-efficient), and Kukri (Zn-inefficient)

• Zn fertilisation: 0 0 1 and 1 0 mg/kg• Zn fertilisation: 0, 0.1, and 1.0 mg/kg

• Zn source: ZnEDTA and ZnSO4



Results

Zinc in soilsFertilizers, OM decay....

Total

Different fractionsResidual

Different fractions


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Di t ib ti f diff t f ti f Z i ilDistribution of different fractions of Zn in soils

• Important to understand the Zn fractionation i il f li ti (f tili )in soil for resources application (fertilizers)

• Previous studies: soil properties influence the transport of trace metals the soil-crop p pcontinuum…………….

• I looked at the fractions as influenced byI looked at the fractions as influenced by farming practices


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0.6

Distribution of differenct Zn fractions in soils of two farming systems , Dalwallinu

0.5

g

CF BF

0 3

0.4

mg/

kg

0.2

0.3

Zinc

in

0.1

Z

0.0

WS EX SA AS Mn-OX OM AFe-OX CFe-OX

Diff t Z F tiThe UWA Institute of

Agriculture

Different Zn Fractions

Residual and total Zn

12

14

6

8

10

in m

g/kg

2

4

6

Zinc

0

Res -Zn Total - Zn


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Distribution of zinc fractions (%) in soils from the two different farming systems ,

Dalwallinu

Zi f ti C ti l Bi l i l F i

from the two different farming systems , Dalwallinu ----

100Zinc fractions Conventional

Farming systemsBiological Farming systems

708090 CF BF

WS 0.81 0.98EX 1.67 2.63SA 0.27 0.48506070

cent

SA 0.27 0.48AS 0.86 1.18Mn‐OX 2.07 1.94OM 4 87 7 53304050

Per

OM 4.87 7.53AFe‐OX 1.62 3.44CFe‐OX 2.25 1.671020

RES 85.58 80.15Total 100 100

0sum of total fraction Residual Total


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Correlation coefficient among different Zn fractions in soils

WS Ex SA AS MnOx OM O AmFeOx Cr FeOx Res TZn

WS 1.00 0.86 -0.99 0.79 0.93 -0.58 0.70 0.20 0.43 0.80WS 1.00 0.86 0.99 0.79 0.93 0.58 0.70 0.20 0.43 0.80

Ex 1.00 -0.84 -0.50 -0.94 0.87 -0.28 0.15 0.04 -0.40

SA 1.00 0.77 0.93 -0.57 0.71 0.27 0.49 0.83

AS 1.00 0.52 -0.03 0.93 -0.28 0.53 0.85

MnOx 1.00 -0.82 0.41 0.42 0.25 0.60

OM O 1.00 0.16 -0.40 0.28 -0.04

AMFeoX

1.00 -0.10 0.78 0.94

CrFeO 1.00 0.40 0.21xRes 1.000 0.86

TZ 1 00


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TZnnumbers with red marks are significant ≤ 0.05 probability levels

1.00

Zinc in vegetative tissues and igrains


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There is difference in growth

No visible Zn deficiencysymptoms appeared (4th week)y ( )

0 mg/kg .1 mg/kg 1 mg/kgg/ g

pH 4.9DTPA Zn 0.36 mg/kg


AgricultureWheat (Kukri) grown in conventional soils, Dalwallinu

Zn concentration in wheat shoot grown in different soils for 7 weeks

70

80 Zn 0 mg/kg soil Zn 0.1 mg/kg soil Zn 1mg/kg soil

a 70

80Zn 0 mg/kg soil Zn 0.1 mg/kg soil Zn 1mg/kg soil

grown in different soils for 7 weeks

20

30

40

50

60

bc b

a

bc b

a

b b

a

d dration (m

g/kg)

30

40

50

60 a

dc

b

cd

cb

aa

ration

(mg/kg)

0

10

20

Zn SO4 ZnEDTA ZnSO4 ZnEDTA

d d

Zn con

centr

0

10

20

Zn SO4 ZnEDTA ZnSO4 ZnEDTA

dd d d

Zn concentr

Excalibur Kukri

Biological Farming Systems (Dalwillinu)

Excalibur Kukri

Conventional Farming Systems (Dalwallinu )

Mean values with the same letters are not significantly different by Tukey’s HSD α =Mean values with the same letters are not significantly different by Tukey s HSD α = 0.05

Soils : Significant (Tukey’s HSD α = 0.01)Zn level : Significant (Tukey’s HSD α = 0.01)Zn Source : Significant (Tukey’s HSD α = 0.05)Genotypes : Non-Significant


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Genotypes : Non Significant

Concentration (mg/kg DW) of seed Zn

Farming Wheat ZnSO4(mg/kg soil) ZnEDTA(mg/kg soil)gSystems Genotypes

4( g/ g ) ( g/ g )

0 0.1 1 0 0.1 1

Biological Excalibur 26c 26c 36a 26c 29b 36a

Kukri 22cd 23d 32b 22cd 26c 31b

Conventional Excalibur 21d 23cd 25c 22cd 26c 42a

Kukri 21d 18d 20d 21cd 22cd 27b

Mean values with the same letter are not significantly different by Tukey’s HSD α = 0.05

Soils : Significant (Tukey’s HSD α = 0.05)Zn level : Significant (Tukey’s HSD α = 0.01)Zn Source : Significant (Tukey’s HSD α = 0.05)Genotypes : Significant (Tukey’s HSD α = )


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Genotypes : Significant (Tukey s HSD α = 0.05)

Seed Zn contented

)ent (µg

/se

Zn Con

te

Density of Zn is higher:• Zn fertilizer level and sources (ZnEDTA doing better)


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Zn fertilizer level and sources (ZnEDTA doing better)• Excalibur (Zn efficient genotypes)• Biologically managed soils

Internal mobilization/translocation is better in Zn efficientbetter in Zn efficient Genotypes ??

19-76 mg/kg19 76 mg/kg16 - 65 mg/kg

Excalibur (Zn-efficient) Kukri (Zn-inefficient)

Critical Zn concentration in youngest leaf <15 mg/kg


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Zinc fractions and their relative availability to plant

SN Fractions Availabilit Sources

availability to plant

y1

1 Water soluble (WS) 5: Readily Davis and Leckie1978Nalovic 1978, 2 Exchangeable (EX) 5: Readily

pHpHClay contentClay content ,

Lindsay 1979Liang et al 1990,Sharad et al 2001,Alvaraz, et al 2006

2 Exchangeable (EX) 5: Readily3 Specifically adsorbed (SA) 3: Available4 Acid soluble (AS) 3: Available

Clay content Clay content OM contentOM contentSoil typesSoil types et.al.,2006

Adhikari et al 2007, Rico, et al 2008

5 Manganese (Mn)-oxide-occluded (Mn-OX) 2:Limited 6 organic matter occluded (OM) 3: Available

h ( ) d b d ( )

Soil typesSoil types………..………..

7 amorphous iron (Fe)-oxide-bound (AFe-OX) 0-2 limited8 crystalline Fe-oxide-bound (CFe-OX) 0-2 limited9 Residual (RES) 0-1 limited

Capacity of plant Capacity of plant to to solubalizesolubalize9 Residual (RES) 0-1 limited

10 Total inactive forms of inactive forms of ZnZn


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10 as least to 5 as very highZnZn

Correlation coefficient among shoot and seed Zn concentration, and different Zn fractions in soils

SN Fractions Shoot Zn Seed Zn

1 Water soluble (WS) 0.66* 0.71*2 Exchangeable (EX) 0.55* 0.88**3 Specifically adsorbed (SA) 0 25 0 393 Specifically adsorbed (SA) 0.25 0.394 Acid soluble (AS) 0.08 0.52*5 Manganese (Mn)-oxide-occluded (Mn-OX) 0.25 0.68*g ( ) ( )

6 organic matter occluded (OM) 0.75** 0.54*7 amorphous iron (Fe)-oxide-bound (AFe- 0.31 0.357 p ( ) (

OX)0.31 0.35

8 crystalline Fe-oxide-bound (CFe-OX) 0.27 -0.399 R id l (RES) 0 08 0 139 Residual (RES) 0.08 -0.1310 Total (TZn) 0.84** 0.37* and ** are significant at 0.05 and 0.01 probability levels, respectively


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and are significant at 0.05 and 0.01 probability levels, respectively

Harmsen 1977, Sharad et al 2001, Adhikari et al, 2007

Conclusions:• Biologically managed soil has higher proportion of available and

total Zn content than conventionally managed soils• More inactive forms in conventional than biological soil (residual• More inactive forms in conventional than biological soil (residual

pool=85% vs 80%)

• Important fractions for crop nutrition i e water solubleImportant fractions for crop nutrition i.e. water soluble, exchangeable, acid soluble and organically-occluded fractions are higher in biological than conventional soil

• Excalibur (Zn-efficient genotype) loaded significantly more Zn (31-85 mg/kg DW) into grains than Zn-inefficient Kukri (21-65 mg/kg DW) (translocation of shoot Zn into seed ) -- breeding

• ZnEDTA fertiliser was more effective than ZnSO4, but relatively high cost limits the practical use of ZnEDTA

• Growing/promoting grain legumes or crops that can solubalizethe inactive forms of Zn to plant (Biological farming approach to be promoted)


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p )

AcknowledgementsAcknowledgements

• UWA/IPRS scholarships• ARC linkage project (with DAFWA and ERAARC linkage project (with DAFWA and ERA

sustainable)• W/Prof. Z RengelW/Prof. Z Rengel• Hossein Saberi• Paul Damon, Mike SmirkPaul Damon, Mike Smirk • ……..


AgricultureThis is the way to my home

Conclusions:• Biologically managed soil has higher proportion of available and

total Zn content than conventionally managed soils• More inactive forms in conventional than biological soil (residual• More inactive forms in conventional than biological soil (residual

pool=85% vs 80%)

• Important fractions for crop nutrition i e water solubleImportant fractions for crop nutrition i.e. water soluble, exchangeable, acid soluble and organically-occluded fractions are higher in biological than conventional soil

• Excalibur (Zn-efficient genotype) loaded significantly more Zn (31-85 mg/kg DW) into grains than Zn-inefficient Kukri (21-65 mg/kg DW) (translocation of shoot Zn into seed ) -- breeding

• ZnEDTA fertiliser was more effective than ZnSO4, but relatively high cost limits the practical use of ZnEDTA

• Growing/promoting grain legumes or crops that can solubalizethe inactive forms of Zn to plant (Biological farming approach to be promoted)


Agriculture

p )

Basu Dev Regmi.ppt - The UWA Institute of Agriculture ...€¦ · Basu Dev Regmi School of Earth...

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