Contribution of Plant Mineral Nutrition to Global Food ... · Plant Mineral Nutrition • The study...
Transcript of Contribution of Plant Mineral Nutrition to Global Food ... · Plant Mineral Nutrition • The study...
-
Contribution of Plant Mineral Nutrition to Global Food Security
Philip J. White
Environment Plant InteractionsProgramme at SCRI
UWA Institute of Agriculture, 1st February 2011
-
Babylonian Proverb
A man who has food has many problems
A man who has no food has only one
UWA Institute of Agriculture, 1st February 2011
-
Outline of Talk
• Plant Mineral Nutrition
Principles of Plant Mineral NutritionA Short History of Mineral Fertilisers
• Food Security
Challenge 1 – Sufficient FoodChallenge 2 – Nutritious FoodChallenge 3 – Safe Food
• Can We Achieve Food Security?
-
Plant Nutritional Requirements
• Plants are capable of making all necessary organic compounds from inorganic compounds and elements in the environment (autotrophic)
• They are supplied with all the carbon, hydrogen, and oxygen they need as CO2 and H2O
• All other elements must be obtained (often) from the soil solution by roots
-
Plant Mineral Nutrition
• The study of how plants obtain, distribute, metabolize, and utilise mineral nutrients
• Mineral: An inorganic element
• Nutrient: A substance needed for survival or necessary for the synthesis of organic compounds
-
White & Brown (2010) Ann. Bot. 105: 1073-1080
Essential Mineral ElementsRequired for plant growth and/or reproduction
Cannot be replaced by another element
Have unique physiological or biochemical roles
Essential & Beneficial Elements
-
Essential Elements – Deficiencies & Toxicities
White & Brown (2010) Ann. Bot. 105: 1073-1080
Essentiality Critical Leaf Concentrations (mg g-1 DM)Element Plant Animal Sufficiency ToxicityNitrogen (N) yes yes 15 - 40Potassium (K) yes yes 5 - 40 > 50Phosphorus (P) yes yes 2 - 5 > 10Calcium (Ca) yes yes 0.5 - 10 > 100Magnesium (Mg) yes yes 1.5 - 3.5 > 15Sulphur (S) yes yes 1.0 - 5.0Chlorine (Cl) yes yes 0.1 - 6.0 4.0 - 7.0Boron (B) yes suggested 5-100 x 10-3 0.1 - 1.0Iron (Fe) yes yes 50-150 x 10-3 > 0.5Manganese (Mn) yes yes 10-20 x 10-3 0.2 - 5.3Copper (Cu) yes yes 1-5 x 10-3 15-30 x 10-3Zinc (Zn) yes yes 15-30 x 10-3 100-300 x 10-3Nickel (Ni) yes suggested 0.1 x 10-3 20-30 x 10-3Molybdenum (Mo) yes yes 0.1-1.0 x 10-3 1
Sodium (Na) beneficial yes - 2-5Selenium (Se) beneficial yes - 10-100 x 10-3Cobalt (Co) beneficial yes - 10-20 x 10-3Iodine (I) - yes - 1-20 x 10-3
-
Plant Mineral Nutrition and Crop YieldLiebig’s Law of The Minimum
Crop yield is determined bya critical input that is inshort supply: the limitingfactor. This is often N.
Inputs that do not correctthe limiting factor aregenerally ineffective inincreasing yield.
-
Essential Mineral Elements
P=200 kg/ha, K=100 kg/ha
0
5
10
15
20
0 100 200 300 400 500N fertiliser (kg/ha)
DM
yie
ld (t
/ha)
N=500 kg/ha, K=100kg/ha
0
5
10
15
20
0 50 100 150 200P fertiliser (kg/ha)
DM y
ield
(t/h
a)
N=500kg/ha, P=200kg/ha
0
5
10
15
20
0 50 100 150 200K fertiliser (kg/ha)
DM y
ield
(t/h
a)White et al. (2006) In: Potato Biology and Biotechnology,
Advances and Perspectives, pp.739-752
Responses in potato yields to N, P and K fertilisation predicted by simulation models (http://www.qpais.co.uk/)
nitrogen phosphorus potassium
-
Soil Fertilisers are Ancient History
Crop production began
Ancient Chinese using organic manures
Ancient Greeks and Romans using animal manures, composts, bones, plant ash (potash), seaweed, saltpeter (potassium nitrate) as fertilisers, and liming materials to correct soil acidity
Egyptians and Mesopotamians using river silt
10,000 1,000 100 10 1 0years before present
Chemical fertiliser industry began about 250 years ago…
Nitric acid 1771
Chilean Nitrate 1830Ammonium sulphate (from coal) 1830Superphosphate 1842
Nitrogen from the air 1911
-
Nitrogen from the Air (1911)
The Haber-Bosch process, is the production of ammonia from nitrogen and hydrogen gases over an enriched iron or ruthenium catalyst.
The Haber-Bosch process produces about 500 million tons of nitrogen fertilizer per year, mostly in the form of anhydrous ammonia, ammonium
nitrate, and urea, consumes about 1% of the world's annual energy supplyand sustains 40% of the world’s population.
The Haber-Bosch process has been called “the most important invention of the 20th century”.
It “detonated the population explosion”, driving the world's population from 1.6 billion in
1900 to 6 billion in 2000.
Smil (1999) Nature 400, 415; Fryzuk (2004) Nature 427, 498
-
The Green Revolution Norman Borlaug “the man who defused the population bomb”
-
Breeding for Improved Varieties
“Plant Breeding is responsible for about 50% of crop productivity increase over the last century, while the
remainder of the yield increase comes from better crop management (e.g. fertilization, irrigation, weeding)”
Food and Agriculture Organization of the United Nationshttp://km.fao.org/gipb/
-
Fertilisers and The Green Revolution
Grain yields at Rothamsted Broadbalk Field (since 1843)
-
Grain yields at Rothamsted Broadbalk field
0123456789
10
1850 1900 1950 2000
Gra
in (t
/ ha
)
PK + 144 kg N
PK + 48 kg N
Unmanured
Flan
ders
Brim
ston
e
fung
icid
es
wee
dkill
ers
Red
Ros
tock
Red
Clu
bSq
uare
head
M
Squa
rehe
ad M
Red
Sta
ndar
d
Cap
elle
Des
prez
Apol
lo
Fertilisers and The Green Revolution
-
Australian Wheat Yields
Kirkegaard & Hunt (2010) J. Exp. Bot. 61, 4129-4143
-
Production of Commodity Crops (1965-2008)
The use of fertilizers accounts for approximately 50% of the yield increase, and greater irrigation for another substantial part.
Nellemann, et al. (2009) The Environmental Food Crisis, UNEP
-
Crop Production and Resource Consumption
Nellemann, et al. (2009)The Environmental Food Crisis,
UNEP
Increased crop yields are paralleled by increases in:the consumption of nitrogen and phosphate fertilisers
the amount of irrigated landthe use of pesticides
-
Global Increase in Crop Yield
Breeding of improved varieties (especially shorter cereals and disease resistance)
Improved weed control
Improved pest and disease control
Application of fertilisers
Irrigation (especially S and SE Asia)
Evans (1993) Crop Evolution, Adaptation and Yield.Cambridge University Press.
-
Potential Losses to Pests and Diseases(Expressed as % Yield)
Oerke (2006) Crop losses to pests. J. Agric. Sci. 144, 31-43
Crop Weeds Animals Pathogens Viruses TotalWheat 23 9 16 3 50Rice 37 25 14 2 77
Maize 40 16 9 3 69Potato 30 15 21 8 75
Soybean 37 11 11 1 60Cotton 36 37 9 1 82
-
Losses to Pests and Diseases(Expressed as % Yield)
Crop Without Pest Control Using mechanical, biological & chemical control measures
Wheat 50 28Rice 77 37
Maize 69 31Potato 75 40
Soybean 60 26Cotton 82 29
Oerke (2006) Crop losses to pests. J. Agric. Sci. 144, 31-43
-
Postharvest Losses are Significant
Nellemann, et al. (2009) The Environmental Food Crisis, UNEP
There are significant postharvest losses in:Fresh fruits and vegetables
Fluid milkProcessed foods and vegetables
Meat, poultry and fishGrain products
Caloric sweetenersFats and oils
Other foods (including eggs and other dairy products)
-
Food Security - Definition
“Food Security exists when all people, at all times, have physical and
economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an
active and healthy life”
FAO World Food Summit (1996)
-
Challenge 1 – Sufficient Food for Nine Billion
global population is projected to increase from 6.8 billion in 2009to over 9 billion in 2050
Source: UN Population Division, World Population Prospects: The 2008 Revision, medium variant (2009)
-
Feeding The Nine Billion
Source: FAO, USDA, Goldman Sachs Commodity Research
“strong demand will require a substantial increasein acreage, which has been virtually unchanged
for decades”
“in the past demand growth has been met throughyield growth, however the strong demand growth
ahead will create a need for substantialacreage expansion”
-
Feeding The Meat Eaters
Source: FAO, USDA, Goldman Sachs Commodity Research
“food demand is stable, feed demand is rising,and fuel demand is exploding”
-
Projected Contributions (%) to Increased Crop Production between 1997/99 and 2030
Land area expansion
Increase in cropping intensity
Yield increase
All developing countries
21 12 67
Sub-Saharan Africa
27 12 61
Near East/North Africa
13 19 68
Latin America and Caribbean
33 21 46
South Asia 6 13 81East Asia 5 14 81
J Bruinsma (2003) World Agriculture: towards 2015/2030: an FAO perspective. Earthscan Publications Ltd.
-
Land Suitable for Rainfed Crops
Nellemann, et al. (2009) The Environmental Food Crisis, UNEP
-
Yield Gaps
The difference between actual and potential crop production.
“By definition, yield potential
is an idealized state in which a crop grows
without any biophysical limitations other than
uncontrollable factors, such as solar radiation,
air temperature, and rainfall in rainfed systems”
Lobell et al. (2009) Annu. Rev. Environ. Resour. 34, 179-204
-
Global Yield Gap for Wheat
Global aggregated yield gap = 43%(cf. 60% for maize and 47% for rice)
Neumann et al. (2010) Agricultural Systems 103, 316-326
-
Major Contributors to Yield Gaps
Lobell et al. (2009) Annu. Rev. Environ. Resour. 34, 179-204
Biophysical factors Socioeconomic factorsNutrient deficiencies & imbalances (N,P,K,Zn…) Profit maximization
Water stress Risk aversion
Flooding Inability to secure credit
Soil problems (salinity, alkalinity, acidity, iron, aluminum, or boron toxicities, compaction…)
Lack of knowledge on best practices
Weed pressures Limited time devoted to activitiesInsect damage
Diseases (head, stem, foliar, root)
Suboptimal planting (timing or density)
Lodging (from wind, rain, snow, or hail)
Inferior seed quality
-
Analysis of Yield Gaps
A wide range of yield gaps exists – 20 to 80% of yield potential
Estimates most difficult in rainfed conditions
Many irrigated cropping systems have yields at, or approaching 80% of potential – difficult to improve
Closing yield gaps will depend on developing technologies that address husbandry, mineral nutrition, irrigation, soil conditions, crop protection
Lobell et al. (2009) Annu. Rev. Environ. Resour. 34, 179-204
-
Plant Mineral Nutrition and Crop YieldLiebig’s Law of The Minimum
Crop yield is determined bythe limiting factor.
Inputs that do not correctthe limiting factor aregenerally ineffective inincreasing yield.
-
Current Constraints to Crop ProductionWater
-
Current Constraints to Crop ProductionSoil
-
Phytoavailability of Mineral ElementsLimits Crop Production on Many Soils
agricultural soils: acid (35-40%, red), alkaline (25-30%, blue), saline (5%)
crop production is limited by soil pH
wikipedia
-
Phytoavailability of Mineral Elements
• Each element has an optimum pH for availability
• Most elements available between pH 6 to 7
• High pH limits the uptake of P, B, Fe, Zn, Cu and Mn
• Plant roots can acidify the rhizosphere
• Liming can be used to adjust pH if soil is acidic
-
Root Traits for Acid SoilsTarget the Limiting Factor – Aluminium Toxicity
Al exclusion allows roots to grow
Chelate Al in the rhizosphere by releasing organic acids or mucilage at root tip
Raise rhizosphere pH
Increase Al-binding to cell wall
These also improve P acquisition
Sequestering Al in root vacuoles
Delhaize et al. (2007) FEBS Letters 581: 2255-2262
Control
TaALMT1
-
Management for Alkaline Soils
Poor soil structure and a low infiltration capacityOften have hard calcareous layer at 0.5 - 1 m depth
Soil alkalinity is associated with calcium carbonateOr, on alkaline sodic soils, sodium carbonate
Low availability of P, N, Fe, Zn, Mn, Cu and B
Main constraint: lime-induced Fe and Zn deficiencies
The pH of alkaline calcareous soils, where crop production is limited by high pH, Ca2+ and bicarbonate concentrations, can be lowered by the addition of S, Fe-sulphates or aluminium sulphate and fertilisers containing urea, ammonium or phosphate
-
Root Traits for Alkaline Soils Target the Limiting Factor – Iron and Zinc Deficiencies
Rhizosphere acidification
Efflux of organic acidsEfflux of phytosiderophoresEfflux of phenolics
Mycorrhizal associationsBeneficial microbes
-
Management of Saline and Sodic Soils
Toxicities:Na and Cl on saline soilsB and Na on sodic soils
soluble salts accumulate with water flowsnear the surface of the soil
or in subsoil moisture
SSaline soils can be remediated by leaching soluble salts from the soil profile by flushing with fresh water
Sodic soils can be remediated by applying Ca2+, often as gypsum, followed by flushing with fresh water
-
Root Traits for Saline or Sodic SoilsTarget the Limiting Factor – Sodium or Boron Toxicity
Exploitation of “salt-free” zone
Exclusion of Na, B or Cl• Increased expression of B efflux transporters (BOR genes) in roots• Na exclusion from leaves by retrieval from xylem sap (HKT genes)
Prevent apoplastic bypasses
Sequestration in non-vital compartments
Munns & Tester (2008) ARPB 59: 651-681Reid (2010) Plant Science 178: 9-11
-
Efficiencies of Wheat Production(and the most limiting factors in different regions)
Factors affecting yield gaps vary by region and are related to complex social, economic and political processes
Neumann et al. (2010) Agricultural Systems 103, 316-326
-
Can We Produce SufficientFood for Nine Billion?
9.5 billion
Increase Agricultural LandProvide Appropriate InputsPrevent Preharvest LossesPrevent Postharvest Losses
-
Koning & van Ittersum (2009) Curr. Opin. Environ. Sustain. 1, 77-82
Can We Produce SufficientFood for Nine Billion?
we are approaching the necessity of increased yields
by increasing the level of complexityof agricultural systems
and increasing energy inputs
-
research priorities “for advancing global welfare” as ranked by eight of the World’s top economists
SOLUTION CHALLENGE1 Micronutrient supplements for children (vitamin A and zinc) Malnutrition2 The Doha development agenda Trade3 Micronutrient fortification (iron and salt iodization) Malnutrition4 Expanded immunization coverage for children Diseases5 Biofortification Malnutrition6 Deworming and other nutrition programs at school Malnutrition & Education7 Lowering the price of schooling Education8 Increase and improve girls’ schooling Women9 Community-based nutrition promotion Malnutrition
10 Provide support for women’s reproductive role Women
http://www.copenhagenconsensus.com/About%20CC08/The%20Basic%20Idea.aspx
Challenge 2 – Nutritious Food
-
Of the 6 billion people in the world,
60-80% are Fe deficient, over 30% are Zn deficient, 30% are I deficient and about 15% are Se deficient
Mineral Elements with Low Phytoavailability
White & Broadley (2009) New Phytologist 182, 49-84
Of the soils in the world,
25-30% are alkaline with low Fe, Zn, Cu & Mn availability many lack sufficient I and Se for adequate animal nutrition
-
Through Agronomy
the application ofmineral fertilisers
Increasing Mineral Concentrations In Crops
White & Broadley (2005) Trends in Plant Science 10, 586-593White & Broadley (2009) New Phytologist 182, 49-84
Biofortification with selenium
Screening potato genotypes
Through Genetics
select or breed varieties that accumulate minerals
-
Biofortification – Agronomic Strategies
• If mineral elements are absent from the soil they must be applied to crops as soil or foliar fertilisers (plants cannot synthesise mineral elements)
• If mineral elements are present in the soil, either agronomic or genetic strategies are developed to increase their phytoavailability, or mineral elementsmust be added as soil or foliar fertilisers
White & Broadley (2009) New Phytologist 182, 49-84
-
Agronomic Biofortification with Zinc(Anatolia, Turkey)
Cakmak (2004)Proceedings IFS 552
http://www.harvestzinc.org/
-
Agronomic Biofortification with Zinc(Anatolia, Turkey)
Project of 1 million USD
Provided a Net Incomeof 100 million USD p.a.
The International Fertilizer Industry Association (IFA): The Anatolia initiative is oneof the world's first examples of using agricultural practices to address publichealth problems as well as improved crop production, and its successprovides a model for countless other nations. More soils throughout the world lackzinc than any other micronutrient. About 50 per cent of the world populationsuffers from iron and zinc deficiencies, which can be addressed throughthis cost-effective method. (http://www.fertilizer.org/ifa/aw_ 2005.asp).
-
Agronomic Biofortification with Iodine(China)
5% potassium iodate dripped into irrigation canalgiving 10-80 µg / L in water
increased water soluble iodine in soil from 19 to 277 µg / Limproved human and animal iodine status and health
Jiang et al. (1997) Arch. Environ. Health 52: 399-408
-
Mandatory Selenium Fertilisation(Finland)
Enrichment of fertilisers with Se in FinlandIncreased grain Se concentrations
and daily selenium intakesfrom below the RDI to the RDI
Broadley et al. (2006) Proceedings of the Nutrition Society 65, 169-181.
-
Biofortification – Genetic Strategies
• If mineral elements are absent from the soil they must be applied to crops as soil or foliar fertilisers
• If mineral elements are present in the soil, crops can be developed that acquire mineral elements or distribute mineral elements to edible tissues more effectively
• There are physiological constraints associated with the edible tissue consumed
• There are phylogenetic constraints associated with evolutionary events impacting mineral composition
White & Broadley (2009) New Phytologist 182, 49-84
-
Mineral Concentrations of Edible PortionsPhysiological & Phylogenetic Constraints
Movement of mineral elements to edible tissues
White & Broadley (2009) New Phytologist 182, 49-84
-
• Elements of dietary importance: zinc, iron, nitrogen
location of mineral elements in wheat grain
Cakmak et al. (2010) Cereal Chemistry 87, 10-20
Mineral Concentrations of Edible PortionsPhysiological & Phylogenetic Constraints
-
White & Broadley (2005) Trends in Plant Science 10: 586-593
Zn (mg kg-1DM) Ca (mg kg-1DM)Fe (mg kg-1DM)0 100 200 300 400 500 0 100 200 300 400 0 1 2 3 4 0
Brassicaoleracea
(leaves)
Phaseolusvulgaris
(seed)
Triticumaestivum
(seed)
Possible Ca-deficiencyupon transfer from bean-rich to cereal-rich diet
Mineral Concentrations of Edible PortionsPhysiological & Phylogenetic Constraints
-
Pfeiffer & McClafferty (2007) Crop Science 47, S88-S105
Within-Species Variation inConcentrations of Mineral Elements
There is considerable genetic variationin mineral concentrations in edible portions of:
maize, wheat, polished rice, barley, pearl millet, sorghum,beans, cowpea, lentil,
cassava, potato, sweet potato and yams
-
QTL Impacting Mineral Concentrations inEdible Portions of Diverse Crop Species
Few genes underlying QTL for mineral concentrations have been identified
Crop Species Elements QTL Tissue ReferencesRice (Oryza sativa)
FeFe, ZnPhytate
33, 22
graingraingrain
Gregorio et al. (2000)Stangoulis et al. (2007)Stangoulis et al. (2007)
Bean(Phaseolus vulgaris)
Fe, ZnFe, Zn, CaZnFe, Zn, CaFe, ZnPhytateTannin
7, 112, 1, 21013,134
seedseedseedseedseedseedseed
Beebe et al. (2000)Guzmán-Maldonado et al. (2003)Cichy et al. (2005)Gelin et al. (2007)Blair et al. (2009)Cichy et al. (2005)Guzmán-Maldonado et al. (2003)
Brassica oleracea Ca, MgFe, Zn
7, 4 leafleaf
Broadley et al. (2008)Broadley et al. (2010)
Brassica rapa Ca, Mg, CuFe, ZnPhytatePhytate
0, 1, 01, 252
leafleafleafseed
Wu et al. (2008)Wu et al. (2008)Zhao et al. (2007)Zhao et al. (2007)
Potato(Solanum tuberosum)
Fe, ZnCa, Mg, Cu
tubertuber
White et al., unpublishedWhite et al., unpublished
-
Summary – Sufficient Food – Increasing Yields
plants require at least 14 mineral nutrientssupplying these in fertilisers has increased crop yields
yields still limited by phytoavailability of mineral nutrients
in the immediate future need to address “yield gaps”yield gaps can be addressed through agronomy
and/or germplasm can be developed for hostile soils
reduce losses to pests and diseasesreduce postharvest wastage
need to produce more with less resource
roots of the second green revolution…
-
Summary – Nutritious Food – Biofortification
many people are at risk of mineral deficienciesagronomic biofortification of crops can be successful
if minerals are present in the soilcrops can be developed to accumulate them
there are physiological and phylogenetic constraintsto the accumulation of minerals
there is significant variation between genotypesin mineral acquisition and accumulation in edible tissues
roots of the second green revolution…
-
Plant Roots Acquire Mineral Elements(provided they are available in the soil solution)
Lynch JP (2007) Roots of the Second Green Revolution. Australian Journal of Botany 55, 493-512.
-
Contribution of Plant Mineral Nutrition to Global Food Security
Sufficient, Safe & Nutritious Food