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 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 1 st. Controlled cross –Can’t replant seed

Degree Days (Heat Units) to emerge to reach Anthesis (flower) Another 1200 – 1300 to reach physiological maturity

Calculating a degree day (Max. Temp. + Min. Temp.) - 50 _______________________ 2 50 = base temp for corn Used to determine planting dates.

AccumulatedRelative GDD (Heat Units)Maturity (Days)

Growth Stages – Table 21-1 Vegetative VE = emergence V1 = first leaf V2 = second leaf V3 = third leaf Vn = nth leaf VT = tasseling Reproductive R1 = silking R2 = blister R3 = milk R4 - dough R5 = dent R6 = physiological maturity

Seed bed prep Fine, Firm, Moist –Disk stubble 1-2x –Chisel –Disk 1x – ring roller –Pre-irrigate –(Fertilize – Dry) –Disk 1-2x –(NH 3 ) –Herbicide, Cross disk, Harrow –Plant

Seed bed – Double crop 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 Nitrogen lbs. Phosphate120 lbs. Potash270 lbs. Sulfur40-45 lbs. Magnesium50 lbs. Calcium60 lbs. Iron3 lbs. Manganese2.5 – 3 lbs. Zinc.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 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 Min. lb limits of test weight (lb/bushel) Max. % limits of Damaged kernels Heat Total Broken corn & foreign material

Diseases 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 Beet Armyworm Western Striped Armyworm Corn Earworm Cutworm Grasshopper

Western yellow striped Armyworm

Beet Armyworm

Corn Earworm

Cutworm

Grasshopper