Micronutrient Needs for Crops on the Southern Plains

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Micronutrient Needs for Crops on the Southern
Plains

• Dave Mengel
• Professor of Soil Fertility
• Kansas State University

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The Essential Elements

• Carbon, Oxygen, Hydrogen
• Macronutrients
• N, P, K
• Secondary Nutrients
• Ca, Mg, S
• Micronutrient metals
• Fe, Zn, Mn, Cu, Ni
• Other micronutrients
• Cl, B, Mo

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Micronutrient Metals

• Of the five micronutrient metals
• Zinc deficiency is common on corn and grain
  sorghum
• Iron deficiency is common on corn, grain sorghum
  and soybeans
• Manganese deficiency is not common in the region,
  but is of interest due to reports of Manganese x
  glyphosate interactions in RR soybeans

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Micronutrient Metals

• Of the five micronutrient metals
• Copper is not a problem in the region, but
  recently foreign experts have been raising
  questions concerning potential Cu deficiencies in
  wheat.
• Nickel is of academic interest only at this time.

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Zinc
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Zinc

• Zinc the most common micronutrient deficiency of
  corn in the region
• Deficiencies also are seen in sorghum, soybeans
  and pecans.
• Deficiencies in wheat and sunflowers are rare.
• A cofactor in many enzyme processes in plants,
  the exact role of the zinc in these reactions is
  generally not known.
• Zinc is generally immobile in the plant, and
  deficiency is commonly noted on the young tissue.
  

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Zinc

• Multiple symptoms have been described for zinc
  deficiency, with some genotypes responding
  differently.
• In corn a stunting, yellowing at the whorl and
  intervienal striping is common.
• A stunting or rosetting and internode shortening
  of young seedlings with distinct white band on
  one side of the mid-rib is also common.

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Zinc Deficient Corn
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Where Zinc Deficiency is Seen

• Zinc is low in many soils across the region, and
  especially in areas of high pH, and where organic
  matter has been removed, such as eroded areas or
  land leveled fields.

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Assessing Zinc Deficiency

• The DTPA Soil Test is commonly used for zinc
• The critical level ranges from 0.5 to 1 ppm Zn
  for most crops
• Levels 0-0.5 considered strongly deficient
• Applications are roughly 1 lb Zn per 0.1 ppm
  below the critical level

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Correcting Zinc Deficiency

• Application of zinc can be by
• Broadcast applications of a high percentage water
  soluble zinc source, such as zinc sulfate,
  oxysulfate or zinc chelate.
• Band application of these same products with
  starter fertilizers.
• Foliar application of zinc, especially on pecans
  and rice.
• Application of animal manure. Most manure
  contains large amounts of zinc

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Iron Chlorosis
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Iron in Plants

• Iron deficiency in field crops is common,
  especially on corn, soybeans, and sorghum. It is
  less common on wheat, but does occur.
• Iron is the most common micronutrient deficiency
  of turgrass and ornamentals in Kansas. Iron
  chlorosis occurs frequently on lawns in new
  developments or on golf greens built with
  unwashed river sand.
• Considerable difference exists between varieties
  in all crops. Corn and soybean varieties are
  screened for iron chlorosis.
• Iron is a structural component of cytochromes,
  hemes and other substances involved in
  oxidation-reduction reactions in photosynthesis
  and respiration.

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Iron Deficiency Symptoms

• Iron is very immobile in plants, once deposited
  in tissue, iron is not easily remobilized to
  younger tissue.
• Deficiency symptoms are generally found in the
  youngest leaves on the plant.
• Young leaves develop an intervienal chlorosis
  that rapidly progresses over the entire leaf.
  This may include a bleaching of the veins and in
  severe cases the entire leaves will turn white.

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Iron Chlorosis in Sorghum
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Iron Chlorosis

• Corn

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Iron Chlorosis
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Iron Chlorosis in Wheat
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Where Does Fe Chlorosis Occur?

• On high pH depressional soils
• Most commonly found in spots in the field
• In eroded spots or leveled areas .

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Assessing Iron Deficiency

• The DTPA test is sometimes used, but it is not
  reliable
• pH and OM may be better indicators

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Correcting Iron Deficiency

• Foliar applications of 2 ferrous sulfate
• May take multiple applications
• Band applications of 6-10 pounds soluble iron
• Animal manure
• Lowering pH works in home hort or turf, but too
  expensive for field applications

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Manganese deficiency
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Manganese in the Plant

• Manganese is involved in photosynthesis,
  particularly in the evolution of O2.
• It also is involved in a number of
  oxidation-reduction reactions and in
  decarboxiliation and hydrolysis reactions.
• In many plant reactions Mn and Mg can partially
  substitute for each other.
• May be a relationship with the RR gene in
  soybeans causing Mn deficiency

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Manganese Deficiency Symptoms

• Like iron, Mn is very immobile in the plant and
  deficiency symptoms occur as intevienal chlorosis
  on young leaves.
• Manganese deficient leaves tend to maintain a
  greenish tint, unlike iron chlorosis where they
  turn yellow or bronze.
• Manganese deficiency is not common in the region,
  but occurs on high pH, high organic matter soils,
  found in the eastern cornbelt.

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Mn and RR Soybeans

• Speculation that the RR gene has added a
  sensitivity to Mn deficiency. Reports and
  research in Indiana and Kansas.
• The yellow flashing which occurs after glyphosate
  application in some fields has been called Mn
  deficiency.
• Research with RR isolines suggest this could be
  the case, but likley on marginal Mn sites.

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Manganese Deficiency

• Corn

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Manganese Deficiency

• Soybeans

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Manganese Deficiency

• Wheat

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Assessing Mn Deficiency

• Mn Soil Tests Dont Work
• pH and OM may be useful in deficient regions
  (eastern US)

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Correcting Mn Deficiency

• Like iron, the soil contains large amounts on Mn,
  its an availability issue.
• Foliar application
• Band application
• Band apply an acid forming fertilizer (N)

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Copper Deficiency
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Where is Copper Deficiency Found?

• Deficiency is not found in the Southern Plains.
  It looks similar to drought or heat damage on
  wheat and has been some confusion recently
• It is common on organic soils in Canada and the
  Great Lakes region, and on organic soils or deep
  acid sands in the southeastern US, which have
  never received applications of copper as a
  fertilizer or as a fungicide.
• On extremely weathered oxisols or sands in
  tropical regions and Australia.

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Copper in Plants

• Copper is involved in many complex enzyme systems
  where redox potential is critical. Examples
  include the enzymes involved in lignin and
  melanin production.

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Copper Deficiency Symptoms

• Corn and wheat are the two commonly grown field
  crops most likely to be deficient in copper.
• Like most metals, copper is not very mobile in
  the plant, with deficiency symptoms occurring on
  the younger tissue.
• Copper deficiency results in a unique necrosis
  and twisting of the leaf tips of young seedlings.
  Copper is bound very strongly by soil organic
  matter..

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Corn
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• Wheat

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Correcting Copper Deficiency

• Broadcast applications of 5 pounds Cu, 20 pounds
  Copper sulfate per acre. Good residual effects.
• Foliar applications of 1-2 pounds Copper sulfate
  per acre.

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Nickel

• Recently confirmed as an essential element.
• Only one field deficiency ever found.
• Primarily of academic interest.

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Micronutrient Non-metals

• Of the three non-metals
• Boron deficiency occurs rarely on alfalfa in SE
  KS and Oklahoma and on peanuts in OK
• Old research found Mo deficiencies on soybeans in
  SE KS
• Recent reports suggest Mo deficiency may occur on
  soybeans in Central Kansas also.
• Chloride response occurs frequently on wheat,
  sorghum and corn in NE and Central KS where no
  potash has been applied.

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Boron
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Boron Deficiency

• Since B is involved in cell division, deficiency
  symptoms are cessation of growth at the terminal
  bud, followed by yellowing and death of young
  leaves.
• Severely impaired fruit and seed set are late
  season symptoms on many crops.
• Boron deficiency is commonly confused with potato
  leaf hopper damage in alfalfa

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Where Boron Deficiency is Seen

• In Kansas, boron deficiency is occasionally seen
  on alfalfa, primarily in SE Kansas.
• There have been reports of boron response in corn
  and sunflower in Nebraska, cotton in Missouri,
  and peanut in Oklahoma.

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Boron Deficient Alfalfa
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Boron Deficiency in Corn
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Boron Toxicity

• Corn

• Soybeans

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Assessing Boron Deficiency

• A hot water soluble soil test is sometimes used
  for boron. However it is not well correlated
  with plant growth, so is not recommended.
• Plant analysis is the preferred diagnostic
  method.
• Since B deficiency is easily confused with
  leafhopper damage, and B toxicity can be a
  problem, care should be used when applying boron

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Correcting Boron Deficiency

• Boron is highly toxic to germinating seeds of
  corn and soybeans. Boron fertilizers should
  never be applied as a "starter fertilizer" in or
  near the row at planting time..
• Application of boron can be by
• Broadcast applications of 1-2 pounds of B as
  granular borate.
• Foliar application of 0.1-0.5 pounds soluble
  borate.

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Chloride
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Background

• Chlorine has been generally accepted as an
  essential element since 1954.
• Responses to chloride fertilization have been
  reported since the 1800s.
• Chloride plays many roles in plant nutrition, but
  role in disease suppression, especially leaf rust
  in wheat and stalk rot in sorghum and corn,
  sparked interest in chloride in Kansas.
• Yield responses to potash on high K soils also
  sparked interest in other states in the plains.

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Chloride Fertilization of Wheat in Kansas

• Some of the first chloride work reported in
  Kansas was done in the early to mid 1980s by
  Larry Bonczkowski comparing KCl to fungicides on
  leaf rust suppression.
• Mark Hooker at Garden City, and Ray Lamond in
  Manhattan followed that up with work on yield
  response to chloride on wheat in the mid-80s.
• Ray Lamond also screened wheat varieties for
  differences in response/sensitivity to chloride.

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RESPONSE OF WHEAT TO CHLORIDE FERTILIZATION IN
KANSAS, 1990-2006. _____________________________
__________________ Chloride applied
Grain Yield Percent Chloride lbs
Cl-/acre bu/A in leaf at boot
_______________________________________________
0 48.4 b 0.29 c 10 51.7
a 0.38 b 20 52.5 a 0.43 a LSD 0.05
1.3 0.03 n 34
30 __________________________________________
_____
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Sorghum 1996 to date

• Unlike wheat, no visual chloride deficiency
  symptoms have been described on sorghum.
• There appears to be a relationship in sorghum
  between chloride nutrition and stalk quality.
• The first chloride studies on sorghum were
  conducted by Lamond in 1996.
• 23 chloride response trials on dryland sorghum
  have been reported, by several people, primarily
  in central Kansas.

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Response of dryland grain sorghum to applied
chloride fertilizer in Kansas,
1996-2006. _______________________________________
_________________ Chloride applied Grain
Yield Percent Chloride in leaf lb
Cl-/acre Bu/A at boot, percent
__________________________________________________
______ 0 98.5 b 0.10
c 20 108.2 a 0.24 b
40 109.9 a 0.33 c LSD 0.05
2.4 0.05 n 20
11 ______________________________________________
__________
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Corn 1996 to 2001

• Like sorghum, no visual chloride deficiency
  symptoms have been described on corn.
• There appears to be a relationship in corn
  between chloride nutrition and stalk quality.
• The first chloride studies on corn were conducted
  by Lamond in 1996.
• Only 11 chloride response trials on dryland corn
  have been reported, all in central Kansas.

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Response of dryland corn to applied chloride
fertilizer in Kansas, 1990-2001. ________________
____________________________________________
Chloride applied Grain Yield Percent
Chloride lb Cl-/acre Bu/A
in earleaf at tassel _________________
___________________________________________
0 104.4 b 0.17 c 20
108.9 a 0.27 b 40 111.6 a 0.36
c LSD 0.05
3.4 0.05 n 11
11 _______________________________________________
_____________
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Soil test chloride interpretations and fertilizer
recommendations for Kansas. _____________________
_______________________________________ Soil
Chloride in a 0-24" sample Cl Recommended Categor
y lb/acre ppm
lb/acre __________________________________________
__________________ Low lt30
lt4 20 Medium 30-45
4-6 10 High gt 45
gt6 0 _________________
___________________________________________ Recom
mendations for corn, sorghum and wheat only.
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Molybdenum
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Molybdenum in Plants

• Molybdenum is involved in the nitrate reductase
  and nitrogenase systems in plants.
• Plants require very low levels of Mo. In
  legumes, enough molybdenum can be present in the
  seed to meet the needs of the plant. But
  subsequent generations may need additional
  molybdenum.

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Molybdenum Deficiency Symptoms

• Molybdenum deficient plants appear stunted, light
  green and N deficient.

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Molybdenum
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Where Does Molybdenum Deficiency Occur?

• On low pH, weathered soils in SE and SC Kansas.
  Molybdenum deficiency is not common in Kansas,
  but occurs most frequently on old, highly
  weathered acid soils.
• Recent reports suggest low molybdenum in seed may
  be contributing to Mo deficiencies under high pH.

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Assessing Molybdenum Deficiency

• No reliable soil test is currently available.
• Soil pH and seed molybdenum may be better
  indicators of molybdenum needs.
• Plant analysis is a good diagnostic tool.

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Correcting Molybdenum Deficiency

• Liming
• Seed treatment with 1-2 ounces of ammonium
  molybdate.
• Foliar applications of ammonium molybdate of
  2-4ounces per acre.
• Due to the toxic nature of molybdenum to ruminant
  animals, molybdenum fertilization is normally not
  recommended.

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Questions?