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

Understanding Emergence & Stand Problems in No-Till Corn

R.L. (Bob) NielsenAgronomy Dept., Purdue UniversityWest Lafayette, IN 47907-1150ph. (765) 494-4802Internet: [email protected]

Feb '98 RLNielsen, Purdue Univ. 2

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!”


Why Worry About Variable Stand Establishment?

Only because uniform and vigorous stands of corn are required for attaining optimum yields.


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.


What isStand 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?


Successful Germination & Emergence Require...• Adequate Soil Temperatures

– Consistently greater than 50o F


Typical Soil Temperatures

0

50

Date

Bar

e S

oil

Deg

rees

F

0

7

14

21

28

35

42


Soil Temperature & Corn Emergence

0

50

20-Mar 3-Apr 17-Apr 1-May 15-May 29-May 12-Jun 26-Jun

Planting Date

Bar

e S

oil

Deg

rees

F

0

7

14

21

28

35

42

Day

s A

fter

Pla

nti

ng

Avg. Daily Soil Temp.

Days to Emergence

WC Indiana, 1993


Successful Germination & Emergence Require...• Adequate Soil Temperatures

• Adequate Soil Moisture– Too wet = Dead kernel– Just right = Germination– Too dry = Inert kernel


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!


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


Germination & Emergence Success Do Not Guarantee Successful Stand Establishment!

What other secretsdo you know?


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’.


Corn Mesocotyl

• Tubular, white, stemlike tissue that connects kernel and base of coleoptile.

• Mesocotyl cell elongation elevates coleoptile to soil surface.


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


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.

– Minimal uptake of water & nutrients.

– Cease new growth shortly after seedling emergence.


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.


Growth Stage VE (Emergence)

Seminal rootsSwelling of 1st nodal roots


Growth Stage V2 (two leaf collars)

1

2

Seminal roots

1st set of nodal roots


Growth Stage V5 (five leaf collars)

Nodal roots1

3

5


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


Root Trivia Question...

Do roots grow TOWARD water and nutrients?

“Water at 1 foot, sir!”“DIVE! DIVE!”


Root Trivia Answer...

No!Root growth occurs where conditions are favorable, not in anticipation of favorable conditions.


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?


Root Location Depends On...

• In some fields, root depth is dependent on the presence of soil compaction or hard pans.


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.


What’s Different About No-Till?


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.


Bad Effects of Trash...

• Delays soil drying and warmup– Delays or causes uneven germination– Hinders early root & shoot growth


If Seedling Growth is Slow...

• Increases exposure time to damaging soil-borne 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!


Tillage Effects on Soil Temperature

66

62.5

60

61

62

63

64

65

66

67

Degre

es F

PlowNo-Till

• 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. Average temperatures during

1st five weeks after planting.

1991-93, westcentral INContinuous corn, SiCL



• Delays soil drying and warmup

• Can hinder planter operation, especially when accompanied by wet soils.


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!

Pinned residueKernel


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


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


A problem related to slot closure...

Example: 1993 growing seasonSandy loam soilPrevious crop = SoybeanPlanted “on the wet side”Trouble closing the slots25+% emerging underground

Farmer: “Must be fertilizer dealer’s fault!”


Normal Emergers

• Growth stage ~ V2

• Seeding depth ~ 1”

• Reasonable rooting


Delayed Emergers

• Leafed out underground

• Trying to pull itself out

• Fairly dense soil surface


Another Example

• Delayed emergence

• Leaves emerged just below soil surface, but successfully

Coleoptile


Brush the soil away and you see...

• Flattened coleoptile• Flattened mesocotyl• Smooth compacted

sidewalls“Smooth as a baby’s ….”


Side View of Delayed Emerger

• Flattened coleoptile

• Flattened mesocotyl

• Smooth compacted sidewalls


Top View of Delayed Emerger

• Seminal root growth confined to furrow


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



• 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



• 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


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 significantstand loss

• Replanted June 26Farmer: “Must be chemical dealer’s fault!”


Appearance of Survivors

• Stunted growth

• Deformed growth

• Prominent tillering

• Unusual leaf stripes


Deformed Inner Stalk Appearance

• Split stalks revealed “gnarly” “innards”


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


So What’s A Guy To Do?

• Planting date


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!




• Maybe........we should be planting a little later than before?– Let the soil dry some.– Let the soil warm some.



• Maybe........we should plant no-till soybeans before no-till corn?– No-till soybean

establishment seems to be easier



• Planting date

• Hybrid selection


Key Factors forHybrid 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!



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



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.



• Planting date• Hybrid selection

• Planter gadgets


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


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


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


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)


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!


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


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.


Purdue Agriculture

“Farming is a kind of continual miracle wrought by the hand of God.”-- Benjamin Franklin

A Parting Thought...

Documents

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