Micronutrient Management Dorivar Ruiz Diaz Soil Fertility and Nutrient Management
Dec 29, 2015
Micronutrient Management
Dorivar Ruiz DiazSoil Fertility and Nutrient Management
OutlineOverview micronutrients
Factors to be considered
S, Zn, Cl, and Fe
Deficiency symptoms
Fertilization strategies and management
Current studies
Essential MicronutrientsMinor elements or trace elementsIncreased interest in micronutrients
– Higher crop yields and micronutrient removal rates– Declining soil organic matter, a major source of
most micronutrients– N, P and K fertilizers contain lower amounts of
micronutrient impuritiesExcessive levels can cause toxic effects on
plantsIn Kansas: Fe, S, Zn, and Cl. Other micronutrients: B, Mg, Cu, Mn, and Ni.
Organic MatterImportant source of most
micronutrients.
Simple organic compounds as chelates.
S, Zn and B deficiencies are more likely to occur in soils low in O.M.
Deficiencies of Cu and Mn are most common in peat soils.
Soil pH and micronutrient availability
Soil pH affects availability of micronutrients.
In general the solubility and availability of micronutrients are greatest in acid soils and lowest in high pH calcareous soils.
Exception is Mo.
In some soils, high levels of soluble Fe, Al and Mn may be toxic to plants.
Sulfur (S)
Photos by Brian Lang, IA
Soil situations and climatic conditions aggravating deficiency symptoms– Coarse textured soils (sandy soils)– Low organic matter soils– Cold, wet soils
– Slow release of S from organic matter– Low atmospheric deposition
No application from– Manure– Other fertilizers
Sulfur Deficiencies
SS
NN
10 kg SO4/ha = 3 lb S/acre
Sulfur Deposition
Corn Response to Sulfur
J. Sawyer, 2007
Wheat S Rec. (Lb/A) = (0.6 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits
Corn and Sorghum S Rec. (Lb/A) = (0.2 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits
Soybean S Rec. (Lb/A) = (0.4 × Y Goal) – (2.5 × % OM) – Profile Sulfur – Other Sulfur Credits
• Subsoil S may be significant.
• Profile soil test for S, 0-24 inches, also good for nitrate and Cl.
Sulfur Fertilizer Recommendation
Zinc (Zn)
ZincFrequently deficient micronutrientAbsorbed by plant roots as Zn++
Involved in the production of chlorophyll, protein, and several plant enzymes
Deficiency symptoms– Most distinctive in corn with new leaves out
of whorl turning yellow to white in a band between the leaf midvein and margin
Sensitive crops– Corn, sorghum
Soil Situation– Low organic matter, high pH (>7.4), eroded soil– Coarse texture, restricted rooting–High P application in conjunction with borderline or low zinc availability– High soil P alone does not create deficiency
Climatic Conditions– Cool and wet soil
Zinc Deficiencies
Phosphorus and Zinc
Zn deficiency impairs plant P regulation.
Large amounts of starter applied P can enhance Zn deficiency if soil Zn is low and no Zn fertilizer is applied.
P2O5 Zn Yield Leaf tissue
lb/acre bu/acre P, % Zn, ppm
0 0 101 0.14 12
0 10 102 0.16 24
80 0 73 0.73 10
80 10 162 0.41 17Adriano and Murphy, KSU
P and Zn Effects On Corn YieldsP2O5 Zn B’cast Starter
Lb / A Corn Yield (Bu/A) 0 0 107
0 10 121 115
40 0 121 93
40 10 139 140
St. Mary’s, KS – Kansas State University
Wheat response to foliar Zn and Cuwestern Kansas
• 1 lb/acre Zn• 1 lb/acre Cu• Control
B. Olson, 2009
Soil Test
Year Site Variety Copper Zinc
- - - - ppm - - - -
2007 1 Danby 1.0 1.3
2 Jagalene 1.0 1.0
3 Wesley 1.0 0.7
4 Jagalene 0.7 0.8
2008 1 Jagalene 0.6 0.2
2 Ike 1.0 1.2
3 TAM111 1.2 0.6
Wheat response to foliar Zn and Cuwestern Kansas
B. Olson, 2009
Treatment Yield2007 2008
- - - - - bu/acre - - - - Zinc 63 42Copper 65 40Control 63 42LSD (0.05) NS NS
Zinc Fertilizer Recommendation
Corn, Sorghum and Soybeans Zinc Recommendation
Zn Rate = 11.5 – (11.25 × ppm DTPA Zn)
If DTPA Zn > 1.0 ppm then Zn Rec = 0If DTPA Zn <= 1.0 ppm then Minimum Zn Rec = 1
Application MethodsBroadcast
– Preferred to correct a low Zn soil test– 5 to 15 pound will increase soil test for a number of
years– Inorganic Zn is more economical than chelates at
these ratesBand
– Very efficient method of applying Zn– 0.5 lb Zn/Acre of inorganic Zn is generally sufficient– Annual applications will be needed for low testing
soils
Chloride (Cl)
Chloride (Cl) Wheat, corn, sorghum deficiencies in Kansas
Deficiencies most likely in higher rainfall areas with no K application history - central and eastern part of state
Soluble, mobile anion
Addition of KCl– Increased yields with high levels of available K– Reduced incidence of plant disease– Internal water relationships, osmotic regulation, enzyme
activation and other plant processes
Chloride fertilization for wheat and sorghum, in Kansas
Chloride rate Wheat yield (Var. 2145)
lb/acre bu/acre
0 66
10 71
20 71
30 73
LSD(0.05)= 3B. Gordon, 2009
Wheat response to Cl and fungicide application
Overley wheat yieldChloride rate No fungicide Fungicide
lb/acre - - - - - - - - bu/acre - - - - - - - - -0 48 54
10 57 6220 60 6430 60 64
LSD(0.05)= 3
B. Gordon, 2009
Grain Yield
Chloride Marion Co. Saline Co Stafford Co.
Rate Site A Site B Site A Site B Site C Site D Site A Site B Avg.
lb/a - - - - - - - - - - - - - - - - - - - - - bu/a - - - - - - - - - - - - - - - - - - - -0 45 80 51 89 83 70 73 64 69
20 47 85 54 89 90 75 80 70 74
Soil test Cl, lb/a (0-24")
7 7 14 22 7 14 7 15 12
*Average over either 12 or 16 varieties. Soil test Cl, lb/a (0-24")
Chloride Fertilization on Wheat
Cl Fertilizer Recommendation
Profile soil Chloride Chloride recommendation
ppm lb/acre lb Cl/acre
< 4 < 30 20
4 - 6 30 - 45 10
> 6 > 45 0Wheat, corn and sorghum
Iron (Fe)Iron in the plant
– Catalyst in the production of chlorophyll– Involved with several enzyme systems
Deficiency symptoms– Yellow to white leaf color– Symptoms first appear on the younger leaves– Wide range of susceptibility of different crops
• Sorghum, field beans and soybeans are more sensitive than corn and alfalfa
• Varieties differ within crops
Iron Deficiency
Iron Deficiency - CausesIron deficiency is caused by a combination of
stresses rather than a simple deficiency of available soil Fe
Soil Chemical Factors– pH, carbonates, salinity (EC), available Fe (DTPA-Fe),
high nitrate-N.– Cool, wet soils
Biotic factors– Variety, SCN, root rotting fungi, interplant competition.
Effect of soil nitrate?
The nitrate theory Iron is part of the chlorophyll molecule
Iron taken up as Fe+++ (ferric)
Iron in chlorophyll exists as Fe++ (ferrous)
High concentrations of nitrate-nitrogen inhibit
conversion of Fe+++ to Fe++
Irrigated soybean
Nitrogen application and iron chlorosis
G. Rehm, 2007
Soybean population and iron chlorosis
2.0
1.51.0Ir
on c
hlor
osis
sco
re5=
Dea
d; 1
=G
reen
Neave, 2004
Soybean population – yield
Neave, 2004Loc.1 Loc.2 Loc.2 0
10
20
30
40
50
bu/a
cre
Soybean Fe Study - 2009Varieties (2): high and low IDC tolerance.Seed treatment: with and without 0.6
lb/acre of EDDHA Fe (6.0%).Foliar treatments:
– 0.1 lb/acre EDDHA Fe (6.0%)– 0.1 lb/acre HEDTA Fe (4.5%)– No foliar treatment
4 locations with 5 replications
ObjectivesEvaluate fertilization strategies.Determine soil parameters (diagnostic):
– Fe, Mg, P, K, Ca, OM, OC, TN, pH, EC, Carbonates, nitrate-N.
Determine “optimum” plant tissue level.Evaluate possible interaction of
parameters, both in soil and plant. – Possible Fe-Mn interaction?
Soybean seed treatment with Fe chelate
Seed coating treatment
No seed coating
EDDHA (6%) HEDTA(4.5%) No Foliar EDDHA (6%).HEDTA(4.5%). No Foliar.
Ch
loro
ph
yll M
ete
r R
ea
din
g
35
36
37
38
39
Yes seed coating
Chlorophyll meter readings
No seed coating
EDDHA (6%) HEDTA(4.5%) No Foliar EDDHA (6%).HEDTA(4.5%). No Foliar.
Ch
loro
ph
yll M
ete
r R
ea
din
g
35
36
37
38
39
40
Tolerant Susceptible
Yes seed coating
Chlorophyll meter readings
Seed coating
No Yes
He
igh
t (i
nch
es)
0
5
10
15
20
25
30EDDHA(6%) HEDTA(4.5%) No foliar
Plant height at maturity
Seed coating
No Yes
Yie
ld (
bu/a
cre)
0
10
20
30
40
50
60EDDHA(6%) HEDTA(4.5%) No foliar
TreatmentAverage
yieldW/O Seed coating 396% Foliar 404.5% Foliar 37No 39
W/ seed coating 506% Foliar 524.5% Foliar 49No 49
Var AG3205: Low IC tolerance
Soybean grain yield
Seed coating
No Yes
Yie
ld (
bu/a
cre)
0
10
20
30
40
50
60EDDHA(6%) HEDTA(4.5%) No foliar
Soybean grain yield
Var AG2906: Very Good IC tolerance
TreatmentAverage
yieldW/O Seed coating 366% Foliar 354.5% Foliar 38No 35
W seed coating 506% Foliar 474.5% Foliar 52No 52
Are these yield values significantly different?
Effect F Value Pr > F SignificanceVariety 2.11 0.1487 NSSeed trt 69.6 <.0001 SFoliar 0.05 0.9553 NSVar*Seedtrt 0.19 0.6616 NSVar*Foliar 2.1 0.1268 NSSeedtrt*Foliar 0.1 0.9004 NSVar*Seed*Foliar 0.27 0.7631 NS
Common Iron Fertilizers
Fertilizer Source
Iron Sulfate
Iron Chelates
Other Organics
Manure - best
Fe (%)
19-40
5-12
5-11
??
Manure source
Iron Manganese Boron Zinc Copper
-----------------lb/wet ton---------------------Dairy solid 0.5 0.06 0.01 0.03 0.01Swine solid 19.0 1.09 0.04 0.79 0.50Poultry 3.0 0.61 0.08 0.48 0.66
-----------------lb/1000 gal---------------------Dairy liquid 0.9 0.11 0.03 0.11 0.12Swine liquid 2.5 0.23 0.06 1.03 0.62
Average animal manure micronutrient content
SummaryFe deficiency potential can not be explained well
by a single soil parameter.
Development of an “ soil index” may be the best alternative.
Foliar treatment seems to increase the “greenness” effectively. But seed coating provides higher yield increases.
Select a soybean variety that is tolerant to Fe chlorosis.
Avoid excessive application of nitrogen fertilizer to the crop that precedes soybeans in the rotation.
SummaryIncreased interest for foliar application of
nutrients.Tissue test can provide good indication for
micronutrient needs.Increased interest for mixing micronutrients
with fluid fertilizer for band application.Seed coating with micronutrients is an
alternative.
Questions?Dorivar Ruiz Diaz
www.agronomy.ksu.edu/extension/