Understanding Emergence &
Stand Problems in No-Till Corn
R.L. (Bob) Nielsen
Agronomy Dept., Purdue University
West Lafayette, IN 47907-1150
ph. (765) 494-4802
Internet: rnielsen@purdue.edu
A Common No-Till Lament….
• “Getting a good
stand of no-till
soybeans is easy,
but...
• Getting a good stand
of no-till corn can be
a pain in the rear!”
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Why Worry About
Variable Stand Establishment?
Only because uniform and vigorous
stands of corn are required for
attaining optimum yields.
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Yield Loss From Variable Stands...
• Regardless of tillage, uneven stand
establishment in corn reduces yield potential
from Day 1.
– Yield losses due to uneven stand establishment
can easily approach 7 to 15 bu./ac.
– This yield loss cannot be recovered.
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What is
Stand Establishment Variability?
• Plant Spacing Variability
– How evenly are the seedlings spaced?
• Plant Emergence Variability
– Do all the seedlings emerge the same day?
• Plant Growth Variability
– Do all the seedlings continue to grow vigorously
and uniformly?
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Successful Germination &
Emergence Require...
• Adequate Soil Temperatures
– Consistently greater than 50o F
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Typical Soil Temperatures
Bare Soil Degrees F
42
35
28
50
21
14
7
0
0
Date
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Soil Temperature & Corn Emergence
42
35
28
50
Avg. Daily Soil Temp.
Days to Emergence
21
14
7
0
20-Mar
Days After Planting
Bare Soil Degrees F
WC Indiana, 1993
0
3-Apr
17-Apr
1-May
15-May 29-May
12-Jun
26-Jun
Planting Date
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Successful Germination &
Emergence Require...
• Adequate Soil Temperatures
• Adequate Soil Moisture
– Too wet = Dead kernel
– Just right = Germination
– Too dry = Inert kernel
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Successful Germination &
Emergence Require...
• Adequate Soil Temperatures
• Adequate Soil Moisture
• Adequate Seed-to-Soil Contact
– Seed-to-residue contact is not good!
– Seed-to-rock contact is not good!
– Seed-to-clod contact is not good!
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Successful Germination &
Emergence Require...
• Adequate Soil Temperatures
• Adequate Soil Moisture
• Adequate Seed-to-Soil Contact
• Pest-Free Conditions
– Grubs, wireworms, seedcorn maggots
– Seed rots, seedling blights
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Germination & Emergence Success Do Not
Guarantee Successful Stand Establishment!
What other secrets
do you know?
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Successful Seedling Establishment
Depends On Two Criteria...
• Healthy kernel, seed
roots, and mesocotyl
– Until permanent roots are
established, a seedling
depends primarily on the
energy reserves of the
kernel.
– These energy reserves are
translocated through the
connecting mesocotyl
‘pipeline’.
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Corn Mesocotyl
• Tubular, white, stemlike
tissue that connects
kernel and base of
coleoptile.
• Mesocotyl cell elongation
elevates coleoptile to soil
surface.
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Successful Seedling Establishment
Depends On Two Criteria...
• Healthy kernel, seed roots, and mesocotyl
• Successful establishment of the permanent
(nodal) root system
– Adequate soil moisture
– Adequate soil temperatures
– Adequate soil tilth
– Pest-free conditions
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Practically-speaking, Corn Has
Two Root Systems...
• Seminal roots originate
from the first node
located within the seed
embryo.
– Radicle root and lateral
seminal roots.
– Serve mainly to anchor
seedling.
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– Minimal uptake of water
& nutrients.
– Cease new growth
shortly after seedling
emergence.
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Practically-speaking, Corn Has
Two Root Systems...
• Seminal roots originate from seed embryo
• Nodal roots originate from stalk nodes
– Elongate shortly after seedling emergence.
• First set visible by 1-leaf collar stage
– One set of roots for every below-ground node
plus 1 or more above ground.
– By 6-leaf collar stage, are main roots of plant.
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Growth Stage VE (Emergence)
Seminal roots
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Swelling of 1st
nodal roots
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Growth Stage V2 (two leaf collars)
2
1
1st set of
nodal roots
Seminal roots
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Growth Stage V5 (five leaf collars)
5
3
Nodal roots
1
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In summary,
Critical Period for Seedling Establishment
Is From Emergence to Knee-High
• Damage to the kernel or mesocotyl prior
to establishment of nodal root system will
stunt or kill the seedling
– From about growth stage VE to about V3
• Damage or stress to the 1st few sets of
nodal roots can severely stunt corn plant.
– From about growth stage V3 to about V6
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Root Trivia Question...
Do roots grow TOWARD water and
nutrients?
“Water at 1 foot, sir!”
“DIVE! DIVE!”
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Root Trivia Answer...
No!
Root growth occurs
where conditions are
favorable, not in
anticipation of
favorable conditions.
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A related root question….
If roots develop
where conditions are
favorable, what are
the primary factors
that determine
whether roots
develop shallow or
deep in the soil?
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Root Location Depends On...
• In some fields, root
depth is dependent on
the presence of soil
compaction or hard
pans.
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More importantly,
Root Location Depends On...
• Soil temperature & moisture in May & June
– Warm, dry soils encourage deep rooting.
– Cool, wet soils encourage shallow rooting.
Among other things, root location affects crop’s 1) nutrient
uptake patterns and 2) drought tolerance.
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What’s Different About No-Till?
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Trash, trash, and more trash!
• TRASH: Stover, stubble, and other plant
materials left from previous crops or weeds
that directly or indirectly interferes with corn
germination, emergence, & seedling growth.
• RESIDUE: Stover, stubble and other plant
materials left from previous crops or weeds
that conserve soil moisture and improve soil
tilth.
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Bad Effects of Trash...
• Delays soil drying and warmup
– Delays or causes uneven germination
– Hinders early root & shoot growth
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If Seedling Growth is Slow...
• Increases exposure time to damaging soilborne pathogens, insects or pesticides.
• Delays roots’ encounters with soil nutrients.
• Decreases the effective length of the
growing season.
– No-till corn is often literally younger than
conventional till corn planted same day!
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Tillage Effects on
Soil Temperature
67
66
Plow
No-Till
66
Degrees F
65
64
62.5
63
62
61
60
Average temperatures during
1st five weeks after planting.
1991-93, westcentral IN
Continuous
corn, SiCL
Feb '98
• No-till averaged 3-4
fewer soil-based GDD
per day than plow.
• Over 5 weeks of
growth, translates to
about 2 leaf stage
delay in development
for no-till.
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Bad Effects of Trash...
• Delays soil drying and warmup
• Can hinder planter operation, especially
when accompanied by wet soils.
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Surface Trash and/or Wet Soil =
Nightmare For Planters!
• Hairpinning of residue into slot
– Wet residues are difficult to cut
– Wet, soft soil = sponge-like cutting board
– Dull coulters do not help!
Kernel
Pinned residue
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Surface Trash and/or Wet Soil =
Nightmare For Planters!
• Hairpinning of residue into slot
• Uneven seed depth
– Caused by uneven residue distribution and/or
excessive planting speeds
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Surface Trash and/or Wet Soil =
Nightmare For Planters!
• Hairpinning of residue into slot
• Uneven seed depth
• Decreased closing wheel effectiveness
– Insufficient down pressure = Open planter slots
– Excessive down pressure = Compacted furrow
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A problem related to slot closure...
Example: 1993 growing season
Sandy loam soil
Previous crop = Soybean
Planted “on the wet side”
Trouble closing the slots
25+% emerging underground
Farmer: “Must be fertilizer dealer’s fault!”
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Normal Emergers
• Growth stage ~ V2
• Seeding depth ~ 1”
• Reasonable rooting
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Delayed Emergers
• Leafed out underground
• Trying to pull itself out
• Fairly dense soil surface
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Another Example
• Delayed emergence
• Leaves emerged just
below soil surface, but
successfully
Coleoptile
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Brush the soil away and you see...
• Flattened coleoptile
• Flattened mesocotyl
• Smooth compacted
sidewalls
“Smooth as a baby’s ….”
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Side View of Delayed Emerger
• Flattened coleoptile
• Flattened mesocotyl
• Smooth compacted
sidewalls
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Top View of Delayed Emerger
• Seminal root growth confined to furrow
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Surface Trash and/or Wet Soil =
Nightmare For Planters!
• Hairpinning of residue into slot
• Uneven seed depth
• Decreased closing wheel effectiveness
• Sidewall compaction in furrow
– Caused by double-disc openers
smearing sides of furrow
– Can cause delayed emergence or leafing out
underground
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Bad Effects of Trash...
• Delays soil drying and warmup
• Can hinder planter operation
• Surface trash harbors disease inoculum that
can cause...
– Seedling blights
– Leaf diseases
– Root and stalk rots
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Bad Effects of Trash...
• Delays soil drying and warmup
• Can hinder planter operation
• Surface trash harbors disease inoculum
• Surface trash favors pesky critters
– Slugs
– Seedcorn maggot
– Brown stinkbug
– Stalk borer
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You be the detective….
•
•
•
•
Originally no-till planted May 20
Northeast Indiana
Corn emerged fine
Began to “suffer” at
“two to three” leaf stage,
resulting in significant
stand loss
• Replanted June 26
Feb '98
Farmer: “Must
chemical
dealer’s fault!”46
RLNielsen,be
Purdue
Univ.
Appearance of Survivors
•
•
•
•
Stunted growth
Deformed growth
Prominent tillering
Unusual leaf stripes
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Deformed Inner Stalk Appearance
• Split stalks revealed
“gnarly” “innards”
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What’s Your Diagnosis?
• The stunting, deformed growth, necrotic leaf
stripes, tillering and “gnarly innards” are all
symptomatic of physical injury near to the
growing point at an early stage of
development.
– Hail or frost damage
– Stinkbug injury
– Stalk borer injury
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So What’s A Guy To Do?
• Planting date
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Planting Date Management
• How many no-till corn growers plant as early
or earlier than in conventional tillage?
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Planting Date Management
• How many no-till corn growers plant as early
or earlier than in conventional tillage?
After all, no-till ground supports equipment pretty dang well!
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Planting Date Management
• How many no-till corn growers plant as early or
earlier than in conventional tillage?
• Maybe........we should be planting a little later
than before?
– Let the soil dry some.
– Let the soil warm some.
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Planting Date Management
• Maybe........we should
plant no-till soybeans
before no-till corn?
– No-till soybean
establishment seems
to be easier
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So What’s A Guy To Do?
• Planting date
• Hybrid selection
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Key Factors for
Hybrid Selection for No-Till...
 Identify consistently superior yielding
hybrids, regardless of tillage system
– Good hybrids in conventional tend to also be
good in no-till
– Multiple location or year data are important
• Performance on “My” farm should NOT be given the
highest priority!
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Key Factors for
Hybrid Selection for No-Till...
 Identify consistently superior yielding hybrids
 Within that group of superior hybrids, select
those with characteristics important to no-till
corn production
– Cold tolerance for germination/emergence
– Strong seedling vigor or early growth habits
– Disease tolerance or resistance
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Key Factors for
Hybrid Selection for No-Till...
 Identify consistently superior yielding hybrids
 Select important no-till characteristics
 Seed quality has greater potential impact in
no-till than in conventional tillage
– The best hybrid in the world can fall apart in
severe no-till situations if seed quality is poor!
– Consider cold germination ratings in addition to
warm germination ratings.
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So What’s A Guy To Do?
• Planting date
• Hybrid selection
• Planter gadgets
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Managing Trash & Cold, Wet Soils
With Planter Gadgets
• Move the trash from the row area
– Before or during planting
– May help warm and dry row zone
– May improve planter operation
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Managing Trash & Cold, Wet Soils
With Planter Gadgets
• Move the trash from the row area
• Cheat & do a little row zone tillage
– Before or during planting
– May help warm and dry row zone
– May improve planter operation
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Managing Trash & Cold, Wet Soils
With Planter Gadgets
• Move the trash from the row area
• Cheat & do a little row zone tillage
• Give the closing wheels some help
– Firming knives or blades
– In-furrow firming wheels
– Furrow sidewall shavers
– Furrow finger fluffers
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Trash Removal or Zone Tillage
Are Attractive For...
• Troublesome no-till seed zones...
– Heavy levels of surface trash
• Continuous corn
• Winter cover crops
• Uneven trash distribution
– Poorly drained soils
– Early planting (cold soils)
– Cooler climates (e.g., northern Corn Belt)
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Seed Firming Contraptions
Are Attractive For...
• Situations where seed-to-soil contact is
inadequate due to poor slot closure
– Primarily wet seedbeds where you have no
business being anyway!
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Bottom Line,
Planter Gadgets May...
• Improve seed placement
– Planter sees “conventional” seedbed
• Improve germination success
– Warmer, drier seed zone
– Improved seed-to-soil contact
• Improve early root development
– Warmer rooting zone
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In Summary,
• Uniform and vigorous stands are essential for
maximum corn yields.
• Key period for successful stand establishment
is from planting to about knee-high.
• Stand establishment in severe no-till
environments can be a challenge.
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A Parting Thought...
“Farming is a kind of continual
miracle wrought by the hand
of God.”
-- Benjamin Franklin
Purdue Agriculture
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