Transcript Slide 1

Corn
• Single most important crop in the US
• 20% of all crop land is planted in corn
• Corn belt
– Iowa, Illinois, Nebraska, Minnesota, Indiana,
and Ohio
• The corn belt accounts for 80% of all
corn grown in the US.
Corn
• Is grown in every state except Alaska.
• Corn was produced as early as 6000 BC
• It can be grown at below sea level to
13,00 feet.
• It is a warm season crop
Uses Feedstuffs
– 12% Silage
– 83% Feed, Seed
– 5% Mixed Feed
Foodstuffs
• Wet Milled – Starch, Syrups, Oils
• Dry Milled – Meal, Flour, Hominy Grits,
Breakfast Cereals, Corn nuts
Types of Corn pg 589
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Dent – Silage, Grain
Flint – Hard
Flour – Indian Corn
Pop – Extreme form of flint corn
Sweet – Mutant of dent corn
Waxy – Soft kernel, adhesives, baby food,
puddings, pie filling, tapioca, clam
chowder.
• Pod - Primative
• Syrup - Karo
Commercial Varieties
• Open-Pollinated –OP’s, save and replant
the seed.
• Hybrid – 1877 the 1st. Controlled cross
– Can’t replant seed
Degree Days (Heat Units)
• 100-150 to emerge
• 1400-1500 to reach Anthesis (flower)
• Another 1200 – 1300 to reach
physiological maturity
Calculating a degree day
• (Max. Temp. + Min. Temp.) - 50
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50 = base temp for corn
Used to determine planting dates.
Accumulated
Relative
GDD (Heat Units)
Maturity (Days)
1750-1850
70
1850-1950
75
1950-2050
80
2050-2150
85
2150-2250
90
2250-2350
95
2350-2450
100
2400-2500
105
Growth Stages – Table 21-1
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Vegetative
VE = emergence
V1 = first leaf
V2 = second leaf
V3 = third leaf
Vn = nth leaf
VT = tasseling
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Reproductive
R1 = silking
R2 = blister
R3 = milk
R4 - dough
R5 = dent
R6 = physiological
maturity
Seed bed prep
• Fine, Firm, Moist
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Disk stubble 1-2x
Chisel
Disk 1x – ring roller
Pre-irrigate
(Fertilize – Dry)
Disk 1-2x
(NH3)
Herbicide, Cross disk, Harrow
Plant
Seed bed – Double crop
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Lime, Gypsum, Potash
Disk 1x
Chisel
Disk 1x
Pre Irrigate w/100# N
Disk – Herbicide
Cross Springtooth
Plant in 24 hours
Ring Roll
Seed bed – single crop
• Fall:
– Disk 2x
– Chisel 2x
– Plane 2x
– List
Jan: Cultivate – Lilliston or alloway
Spring : Plant
Seeding Rates
• Ranges between 25,000 to 45,000 plants
per acre.
• 35,000 is optimum (high plantings are
pushing 200 bushels per acre)
– Silage is seeded more closely than this rate.
Crop rotation
• 2 year = corn – small grain
• 3year = corn – small grain – clover
rotation
• 4 year = corn – oats – wheat – clover
rotation
Fertilization
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Nitrogen
Phosphate
Potash
Sulfur
Magnesium
Calcium
Iron
Manganese
Zinc
300-325 lbs.
120 lbs.
270 lbs.
40-45 lbs.
50 lbs.
60 lbs.
3 lbs.
2.5 – 3 lbs.
.5 lbs.
Irrigation
• 18 – 22” of water.
• Critical periods are early tassel, silking,
and blister kernel stages.
• for most corn, that would be 40 – 80 days
after emergence.
Weed management
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Roundup Ultra/RT
Lasso
Atrazine
2,4-D
Basagram
Dual
Prowl
Harvesting
• Kernel Moisture 34%
• Grain corn at 20% moisture
• Sweet corn = milk stage (21 days after
silking)
• Silage corn = when ears are glazed &
most leaves are on the plant, slight dent.
• Fresh Corn at 70% moisture. (can/frozen)
– 5-6% sugar & 10 – 11% starch
Grades
Grading
Factors
#1
#2
#3
#4
#5
54.0
52.0
49.0
46.0
0.1
0.2
0.5
1.0
3.0
3.0
5.0
7.0
10.0
15.0
2.0
3.0
4.0
5.0
7.0
Min. lb
limits of
56.0
test weight
(lb/bushel)
Max. %
limits of
Damaged
kernels
Heat Total
Broken
corn &
foreign
material
Diseases
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Common Rust
Corn Smut
Fusarium Ear Rot
Furarium Stalk Rot
Common Rust
• Symptoms
• Common rust causes
pustules that may appear
on any aboveground part
of the corn plant but
they are most abundant
on leaves. The pustules,
which may erupt and
become powdery, occur
nearly simultaneously on
both leaf surfaces. They
are golden brown to
cinnamon brown,
becoming black as the
spores mature.
Corn Smut
• Common smut is
easily recognized by
the tumorlike galls
that form on any
aboveground plant
part. The
conspicuous galls that
replace kernels are
covered with a
greenish-white papery
tissue.
Fusarium Ear Rot
• white to salmon-pink
discoloration of
individual kernels or
groups of kernels
scattered over the
ear.
Furarium Stalk Rot
• Corn plants with Fusarium stalk rot
exhibit rotting of the roots, plant base,
and lower internodes. The rot normally
begins soon after pollination.
Insects
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Beet Armyworm
Western Striped Armyworm
Corn Earworm
Cutworm
Grasshopper
Western yellow striped
Armyworm
Beet Armyworm
Corn Earworm
Cutworm
Grasshopper