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Micronutrients in agriculture
Are they important?
Wim Bussink (NMI, www.nmi-agro.nl)
October 17, 2013
Nutriënten Management Instituut B.V.
Postbus 250, 6700 AG Wageningen
T: 088 8761280
I: www.nmi-agro.nl
• Micronutrients:
• importance, crop, animal, “human””
• deficiency & critical contents
• Micronutrient status NL, EU, others
• shortage in future
• soil testing & fertilizer
Lay out
• Needed in small quantities
• Necessary for growth and development (plant,
animal, human)
• Most are involved in protein synthesis/activation
• Deficiency symptoms chlorosis within leaves
• Deficiency < --- > toxicity
Stick deficiency photos
http://ppi-store.stores.yahoo.net/crnudeimco.html
Micronutrients
• Boron (B), H2BO3- NL
• Copper (Cu), Cl- NL
• Manganese (Mn), Mn2+ NL
• Zinc (Zn), Zn2+ NL
• Selenium(Se), SeO42- NL
• Iron (Fe), Fe2+ or Fe3+
• Molybdenum (Mo), MoO4-
• Nickel (Ni), Ni2+
• Chlorine (Cl), Cl-
Essential micronutrients (1)
Essential micronutrients, plants
molybdenum essential for nitrogen fixation, cofactor that
functions in nitrate reduction
iron component of cytochromes activates some
enzymes
nickel cofactor for enzyme functioning in nitrogen
metabolites
chlorine required for water-splitting step of
photosynthesis in water balance
Essential micronutrients
boron Cofactor in chlorophyll synthesis, may be
involved in carbohydrate transport and
nucleic acid synthesis
manganese Active in formation of amino acids,
activate some enzymes, required for
water-splitting step of photosynthesis
zinc Active in formation of chlorophyll,
activates some enzymes
copper Component of many redox and lignin-
biosynthetic enzymes
Crop Zn Fe Cu Mn B Mo
_____________________________________________________
beans h h h m
barley m m m m
broccoli m m h h
cabbage m m h m
canola h h h
carrot m m m m
corn h m m m m?
flax h m m
lettuce h h h m h
onion h h h h
potato m h
spinach h h h m h
s. beet m m h h h? m
wheat m h h
____________________________________________________
Sensitivity of some crops
http://eprints.nwisrl.ars.usda.gov/777/1/753.pdfDaves and Westermann, 1991
• Dependent of
• Crop type
• Growth stage
• Where it is measured
• Example Mn: potato
Critical contents
Nutrient Deficient Marginal Critical Suff High Very high
or toxic
Remarks Source
Mn (mg/kg) 40-100 YML before or start flowering 1
30-300 YML begin bloei 4
50-450 YML halverwege knolzetting 4
<30 30-60 >60 YML bij 20-25 cm gewashoogte 7
<30 30-100 >100 YML begin bloei 7
<20 20-100 >100 YML halverwege knolgroei 7
<20 20-100 >100 YML afsterven blad 7
<10 10-20 21-200 201-400 L midden seizoen, einde bloei 14
20-29 30-250 >250 L laat seizoen, halverwege knolgroei 14
7 40 L 15
Example Boron
Shortage:
Sugar beet:
death of growing points in
center of plant, brown fibrous
patches on leaf stems
decrease of sugar content
Poorer development of
maize ear
less nodule development in
legumes
Example: Mn shortage
Also sensitive crops
• oil seed rape
• peas
• beans
• cabbage
• carrots
• lettuce
• onions
Deficiency yield depression up to:
• 20% potato
• 10% sugar beet
• 50% grain
INPUT Mn; strong decrease due to:
• Decrease of Mn containing crop protection products
(maneb, mancozeb)
• Fertilizer less “polluted” with Mn
OUTPUT Mn
• Circa 200 g Mn/ha
OUTPUT > INPUT deficiency possible
especially high pH soils
Induced shortage due to Round-Up use? IFS SympRomheld (2004)
Mn actual
Purdue Work Don Huber
Root uptake Translocation to shoot
Effect of glyphosphate: 2.5% of recommended rate
Examples Mn
Zn
• Enzymes, reproduction, immune defense system
appetite
• Small body reserve• Muscles, bones
• Shortage effects: fast
Cu
• Blood & bone formation, resistance
• Large body reserve
Animals (cattle): Zn and Cu
Se
• Resistance, less muscle damage,
reproduction/fertility,
• Large body reserve• enzyme GSH-Px (red blood cells, organs & tissue)
Co
• Essential for Vit B12
• small body reserve
• liver
Animals (cattle): Se and Co
http://www.oxfordjournals.org/our_journals/tropej/online/mcnts_chap10.pdf
http://www.fao.org/docrep/013/am027e/am027e00.pdf
Micronutrient status NL, EU,
others
Zn deficiency worldwide(mining stocks about 30 yr!!!)
In Europe: Turkey has Zn deficiency problems
Boron deficiency worldwide (after Shorrocks, 1997)
China:Se deficiency as well as to
rich soils China
Europe:Generally to low Finland
fertilization program for over 20
years
Bron: Schaarste van micronutriënten, in bodem,
voedsel en minerale voorraden, 2012
Number of years of supply for essential mineral nutrients (vertical axis)
based on current reserves and consumption levels (data source: USGS,
2011).
Jongvee Vaarzen Oudere koeien Dekkingsgraad (%) <1
jaar >1
jaar 14
dgn 100 dgn
200 dgn
300 dgn
drg 14
dgn 100 dgn
200 dgn
300 dgn
drg
Zomer 198 199 216 210 180 221 191 199 198 181 212 199 Zink
Winter 198 178 216 209 190 229 191 199 198 180 221 199
Zomer 216 72 236 226 168 201 38 205 202 168 184 40 Selenium
Winter 216 71 231 220 161 203 38 200 196 161 186 40
Zomer 139 77 315 319 199 153 44 287 302 216 152 46 Koper
Winter 151 68 340 343 210 175 47 309 324 229 175 50
Zomer 184 99 610 509 459 445 73 503 445 424 414 73 Kobalt
Winter 184 98 594 494 440 434 73 488 431 407 404 73
Often supplementation in dairy cattle
farming: not only in NL
Factors involved in micronutrient
availability
• Total amount
• pH
• Organic matter
• CEC
• Oxides
• Redox potential
• Temperature
• Interaction with
other nutrients
Factors involved in micronutrient
availability
• Soil water content
• Microbial activity
• Mycorrhizas
• Root growth
• Root induced
changes
(phytosiderophores)
• Heavy metals Cu, Ni and Zn
– minimise increase
• Food safety
• Minimise fertilisation costs
– marginal profits in agriculture
• Scarce minimise use:
– stocks Zn, Cu & 30-50 years (USG, 2011)
Requirement of:
• (High quality) testing at a low price
– From single nutrient towards multi-nutrient extraction
Soil and plant testing
• Boost after 1945
• “Aggressive extractants” to measure anything
Variation in micronutrient content of soil and soil solution
Big variation in soil
Element Total content, mmol kg-1
Concentration in soil solution, M
total Ionic form
B 0.100 - 25 1 – 100 1 – 100
Mo 0.002 – 0.38 0.01 – 1.5 0.001 – 1.5
Cu 0.015 – 5.08 0.05 – 0.6 10-5
– 101
Zn 0.05 – 11.6 0.03 – 3.8 10-5
– 103
Mn 0.365 – 167 0.1 – 790 10-1
– 104
Fe 3.5 – 1800 0.3 – 17.1 10-4
– 101
Ni 0.0035 - 6.3 0.01 - 0.425 10-3
– 10-1
Co 0.015 – 5 0.005 - 1.5
Se 0.0008 – 0.25 0.0001- 0.1 10-4
• Trial and error research
Many different soils
• Many (complex) extractants used different fractions• Empirical validation
• Regional basis
• Results outdated NL, Cu & Co 50 yrs old
An overview of extractants used
Many different procedures
1 component 2 components 3 or more components
Water Mehlich 1 Mehlich 2
Dilute salts (CaCl2, NaCl, KCl, Mg(NO3)2 Morgan Mehlich 3
Hot water Wolf-Morgan AAAc-EDTA
DTPA AB-DTPA DTPA+CaCl2+triethanolamine
EDTA Ammonium oxalate CH3COOH+ NH4Cl+citric acid+ HCl
EDDHA CaCl2 +DTPA (ie CAT)
Pyrophosphate EDTA+(NH4)2CO3
Anorganic acids of different strength
(HCl, HNO3, H3PO4, H2SO4)
Citric acid + EDTA
Organic acids of different strength
(citric, acetic)
Hydroquinone
Triethanolamine
• Extractant information
– what is directly available (intensity) (ie 0.01 M CaCl2)
– what can come readily into solution (capacity)
• (strong) acid spectroscopic tech., NIR/MIR/XRF
– multi-nutrient and ICP(-MS) Interactions
• Modelling chemical processes solid phase/solution
• Field and pot trials
New Approach
2011-2014 STW research project Cu, Mn, B, Se
2 AIO’s WU, NMI, Blgg, AKZO, PA, PZ
• Micronutrients, important but often underestimated
• Plant, animal and humans
• Shortage now in many parts of the world
• Diminishing stocks
• To much focus on N, P and K
• Soil and plant testing
Final remarks