Unit D: Production of Field Crops
Lesson 2: Cereal Crops: Maize
Student Learning Objectives: Instruction in this lesson should result
in students achieving the following objectives:
1. Identify maize and its uses.
2. Describe the different types of maize.
3. Describe the soil and climatic requirements of maize plants.
4. Explain the cultural practices of maize production.
Recommended Teaching Time: 3 hours
Recommended Resources: The following resources may be useful
in teaching this lesson:
 A PowerPoint has been developed for use with this lesson plan.
List of Equipment, Tools, Supplies, and Facilities:
Writing surface
PowerPoint Projector
PowerPoint Slides
Transparency Masters
Copies of student lab sheets
A variety of products made from maize
Materials for LS: D2-1
Terms: The following terms are presented in this lesson (shown in bold italics
and on PowerPoint Slides 2 and 3):
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Aflatoxin
Climate
Crown
Cultural practices
Embryo
Endosperm
Fertilizer
Grain
Grain marketing
Grain technology
Growing degree day
Hilum
Husk
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Hybrid
Integrated pest management
Kernel
Palatable
Plant population
Prop roots
Seed coat
Silk
Tassel
Variety
Interest Approach: Use an interest approach that will prepare the
students for the lesson. Teachers often develop approaches for their unique
class and student situations. A possible approach is included here.
Bring in a variety of products made with maize. You may also want to include
nonfood items. Have students compare the items. Ask them to consider what
they have in common. Explain that maize is used in many products, not just what
we eat.
Summary of Content and Teaching Strategies
Objective 1: Identify maize and its uses.
(PowerPoint Slides 4 and 5)
I. Maize is one of the most valuable cereal grain crops grown in the world. It was
domesticated in Mexico around 9000 B.C. A grain is a seed of the cereal grain
plant. Maize, or Zea mays, is a versatile crop. It is used for both human and
animal consumption and its by-products can be used to make numerous nonfood products.
(PowerPoint Slide 6)
A. As a livestock feed, maize is used for fattening. It is also the most
palatable, or good tasting, of the cereal crops. Maize can be used in high
concentrations in dairy cattle feed and is also used in poultry mash. The
kernel is high in starch, which is a carbohydrate, and a good source of
energy.
(PowerPoint Slide 7)
B. A kernel is the part of the individual grain within the seed coat. Maize
kernels are enclosed in a seed coat. A seed coat is the outer covering of
a seed. Inside the seed are the embryo and endosperm. An embryo is an
undeveloped seedling.
(PowerPoint Slide 8 illustrates the parts of a corn kernel)
(PowerPoint Slide 9)
C. Maize kernels contain two types of endosperm: starchy and flinty. The
endosperm is the food for the seedling inside the seed. Starchy
endosperm is soft. Flinty endosperm is hard. The amount of each type
determines how the maize can be used.
(PowerPoint Slide 10)
D. The ends of the maize kernel are referred to as the crown and the hilum.
The crown is the outer end of the maize kernel. The hilum is the point of
attachment on the seed.
(PowerPoint Slide 11)
E. Humans are also consumers of maize and maize/corn products. Common
human food products around the world include corn meal, corn hominy,
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corn flakes, corn chips, corn starch, corn oil, corn syrup, and corn sugar.
And don’t forget about popcorn!
(PowerPoint Slide 12)
F. In many countries, a number of by-products can also be made from the
maize plant. The stalks can be processed into paper, insulation, and
cardboard. The cobs can be processed into pipes, methanol, tar, and
plastic. The cob grit can be used to clean and polish buttons and jewelry.
Corn cob dust can be made into face powder.
(PowerPoint Slide 13)
G. Cereal grain plants are members of the grass or Gramineae family. Maize
plants have fibrous root systems and are supported by smaller roots called
prop roots. Prop roots are above ground roots that aid in keeping plants
erect. The maize kernels grow on ears that vary in size, shape, and color
dependent on variety.
(PowerPoint Slide 14)
Maize ears are enclosed in husks. A husk is the leafy, protective covering
that surrounds ears of maize on the plant. The silk and tassel are the
female and male reproductive parts of the maize plant. The silk is the
female reproductive part of the maize plant. The tassel is the male
reproductive part of the maize plant.
**Have the students get into groups and create a list of all the
uses for Maize in Afghanistan. Use TM: D2-1 to identify the parts of the
maize kernel, and PowerPoint Slide 15 or TM: D2-2 to identify the parts of
the maturing and fully mature maize plant.
**Have the student use LS: D2-1 as an exercise in dissecting a maize seed.
They can use TM:D2-1 as an aid in this lab
Objective 2: Describe the different types of maize.
(PowerPoint Slides 16, 17, and 18)
II. There are six common types of maize. Maize types are classified based on
kernel characteristics. These characteristics are amount, quality, and
arrangement. The six most common types of maize are dent maize, flint maize,
floury maize, popcorn, sweet maize, and pod maize.
(PowerPoint Slide 19)
A. Dent maize, Zea mays indentata is referred to as field maize or field corn.
The crowns of the kernel are dented, giving the maize its name. This
denting occurs when the starch at the end of the crown shrinks during
drying.
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(PowerPoint Slide 20)
Dent maize can be yellow, white, or red in color. The length of the growing
period varies by cultivar. Dent corn provides corn starch and other
byproducts (mentioned in Objective 1) which can be processed into an
assortment of things from biodegradable plastics to fuels.
(PowerPoint Slide 21)
B. Flint maize, Zea mays indurata, is a popular source of maize meal. Most
cultivars mature fairly quickly, even under poor conditions. Flint maize is
resistant to many insects and can be shipped overseas because of its
kernel hardness.
(PowerPoint Slide 22)
This hardness is due to the makeup of the kernel. The center is made up
of only a small amount of soft starch surrounded by a thick layer of hard
starch.
(PowerPoint Slide 23)
Flint maize comes in many colors, including white, yellow, red, and blue. It
can be used decoratively, because they have distinctive and colorful
kernels. When used as a decorative corn, flint corn is sometimes called
Indian corn. The corn also has food use as well, however, and it is grown
on several continents.
(PowerPoint Slide 24)
C. Floury maize, Zea mays amylacea, is also called soft maize. Soft maize
kernels are made up primarily of soft starch with a thin covering of hard
starch.
(PowerPoint Slide 25)
The lack of a thick hard starch layer makes this type of maize a good choice
for flour production. Flint maize comes in several colors, including white
and blue.
(PowerPoint Slide 26)
D. Popcorn, Zea mays everta, cultivars are divided into two classes, pearl
and rice. This division is based on the shape of the kernel. Popcorn
kernels are smaller than flint maize kernels and are made up of a hard,
flinty starch.
(PowerPoint Slide 27)
Some cultivars have a soft starchy center. The kernels are usually white or
yellow but may be red, blue, or brown.
(PowerPoint Slide 28)
When popcorn is “popped” the moisture inside the kernel is heated until it
becomes steam. This causes pressure that causes the kernel to explode.
The white or yellow flaky material is the starch from inside of the kernel,
and is good for human consumption.
(PowerPoint Slide 29)
E. Sweet maize, Zea mays saccharata, is most commonly grown for human
consumption. Sweet maize is picked while still immature to retain the high
sugar content.
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(PowerPoint Slide 30)
Sweet maize kernels are white or yellow and may be wrinkled or become
caramelized in color when fully mature. This is often the corn people
choose to eat in many parts of the world.
(PowerPoint Slide 31)
F. Pod maize, Zea mays tunicata, has little commercial importance and is
commonly grown as a specialty item. Pod maize kernels are enclosed in a
husk or pod and the ear is surrounded by a large husk.
**Bring in samples of as many of these types of maize as you can find.
Point out the differences between the kernels. Refer to TM: D2-3 to review
the spelling of the scientific names.
Objective 3: Describe the soil and climatic requirements of maize plants.
(PowerPoint Slides 32 and 33)
III. Climate is the average weather condition over a long period of time. Grain
crops, such as maize, require moderate rainfall, frost-free temperatures, warm
weather, and sunshine. Medium textured soils will also help to provide optimum
maize yields.
(PowerPoint Slide 34)
A. The variety grown should match the climate of the area. The optimum
temperatures for maize growth are 21.1 to 30° Celsius. Adequate rainfall
is also important. Irrigation is very important when there isn’t a sufficient
amount of water.
(PowerPoint Slide 35)
B. In some parts of the world frost is an issue. Frosts are detrimental to the
production of a quality maize crop. Early frosts cause damage to the plant
by damaging leaves and delaying growth. However, late season frosts
may cause more damage by causing severe leaf injury or death.
(PowerPoint Slide 36)
C. Cereal grains require fertile soil for growth. Specific nutrient requirements
vary by cultivar. Soil pH should be between 5.0 and 8.0.
Objective 4: Explain the cultural requirements of maize production.
(PowerPoint Slides 37 and 38)
IV. Cultural practices are the procedures used in producing a crop. Cultural
practices include selecting a variety, planting, fertilizing, pest control, and
harvesting.
(PowerPoint Slide 39)
Irrigation is also considered a cultural practice. These practices will vary with
the crop being produced; they may also vary with the type and variety of the
crop.
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(PowerPoint Slide 40)
A. Some parts of the world use hybrid maize. A hybrid is an offspring from
genetically different parents. Hybrids are produced through human
manipulation. Hundreds of hybrids are available for planting; many are
bred for use in local areas. A variety is a plant cultivar that is cultivated
and retains its features when reproduced.
(PowerPoint Slide 41)
B. A variety should be chosen that matures at a good time according to your
areas climate. Days to maturity range from 50 to 330 days.
(PowerPoint Slide 42)
C. Besides days to maturity, maize varieties also vary in height and number of
ears per stalk. Maize plants are commonly 1.8 to 2.4 meters tall but can
grow from .6 to 6.1 meters tall. On the average, maize plants will produce
1 to 3 ears.
(PowerPoint Slide 43)
D. If frost is a factor, planting should occur after the danger of frost has
passed. Soil temperature should be above 10° Celsius at 5 centimeters
deep. In Afghanistan most people try to plant maize between the middle of
April up until the end of June, depending on the region. Germination and
rapid growth is related to the amount of growing degree days.
(PowerPoint Slide 44)
E. A growing degree day (GDD) is a measure of the temperature
requirements for best maize growth.
1. The GDD is figured by adding the maximum temperature and the
minimum temperature in a day, divided by two, and subtract 10.
(PowerPoint Slide 45)
2. 10 is a constant because maize grows very little at 10° C. The
maximum temperature used is 30. This is because temperatures
above 30° C do not increase the rate of growth. Temperatures
above 30 are counted as 30.
(PowerPoint Slide 46)
F. Maize should be planted in a prepared seedbed. This can be done by
working up the land until the soil clods are at a minimum. In some parts of
the world, a seedbed can be prepared by plowing with a chisel or
moldboard plow followed by a disk harrow or do-all. Plowing and disking
reduces soil clods and prepares a fine seedbed.
(PowerPoint Slide 47)
G. Maize is planted in rows 50.8 to 101.6 centimeters apart and 2.5 to 5
centimeters deep. Yields per growing plot increase with narrower rows. If
technology is available, in some areas of the worlds, a planter is used to
open the seed drill and place the seed. This is used for larger scale
planting.
(PowerPoint Slide 48)
H. Planters can be set to achieve a desired plant population. Plant
population is the number of plants growing in one hectare. Plant
populations may range from 24,000 to 32,000 plants per 0.4 hectare.
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(PowerPoint Slide 49)
I. Plant population is easy to calculate. First, determine the row width. Divide
the width in meters into 10,000 (square meters per hectare) to determine
the total length of all rows in a hectare. Divide the number of plants into
the row length to calculate the distance between seed.
(PowerPoint Slide 50)
J. No-till planting requires different techniques and different equipment than a
prepared seedbed. Vegetation is cut and often controlled with chemicals.
Seeds are planted deeper in no-till planting; however, there is less soil
covering the seed.
(PowerPoint Slide 51
K. A healthy maize plant requires a good fertilizer. A fertilizer is a material
added to the soil to provide nutrients to increase plant growth, yield, or
nutritional value of the plant. (Note: Additional information on fertilizers will
be provided in upcoming lessons)
(PowerPoint Slide 52)
L. Integrated pest management (IPM) is a pest management strategy that
uses a combination of measures to reduce pest damage with the least
disruption to the environment. Common maize pests include weeds,
insects, nematodes, and diseases. Besides IPM, planting resistant
varieties can help reduce pest and disease problems. (Note: Additional
information on pest management will be provided in upcoming lessons)
(PowerPoint Slide 53)
M. Maize can be harvested by hand. They will then need to have the husks
removed. In some parts of the world harvesting corn is done with a picker
or a combine. Maize harvesting should be timed for maximum yield.
Harvest dates in Afghanistan can run from anywhere from the beginning
of August to the end of October, depending on the region
(PowerPoint Slide 54 shows a picture of a combine harvesting corn)
(PowerPoint Slide 55)
Grain maize should be harvested at 20 percent to 28 percent moisture.
Higher moisture maize requires increased artificial drying. Maize should
be dried to approximately 15.5 percent.
However, maize in more humid area may need to be dried to 11 percent.
(PowerPoint Slide 56)
The increased drying should help avoid aflatoxin buildup.
An aflatoxin is a highly poisonous substance caused by the fungi
Aspergillus florus in grain. Aflatoxins in animal feed can be deadly.
**Use LS: D2-2 to reinforce the math formula used to figure growing degree
days.
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Review/Summary: Summarize the lesson by asking students to explain
the content of each objective. Reinforce the key terms and concepts. LS: D2-1
and LS: D2-2 will also help serve as a review.
Application: Students can apply the information learned in this lesson to the
following lab sheets: LS: D2-1 Maize Dissection and LS: D2-2 Calculating
Growing Degree Days
Evaluation: Student comprehension of these objectives can be measured
with the attached sample test.
Answers to Sample Test:
Part One: Matching
1 = b, 2 = e, 3 = h, 4 = f, 5 = d, 6 = c, 7 = a, 8 = g
Part Two: Completion
1. plant population
2. Integrated pest management
3. growing degree day
Part Three: Short Answer
1. Hilum, embryo, seed coat, crown, soft endosperm, hard endosperm.
2. Prop roots, ear, silk, tassel, leaf, stem, roots.
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Sample Test
Name_____________________________________
Test
Unit D: Lesson 2: Growing Field Maize
Part One: Matching
Instructions. Match the term with the correct response. Write the letter of the term
by the definition.
a. Aflatoxin
e. Grain
b. Embryo
f. Palatable
c. Hybrid
g. Silk
d. Kernel
h. Tassel
_______ 1. An undeveloped seedling.
_______ 2. A seed of the cereal grain plant.
_______ 3. The male part reproductive part of the maize plant.
_______ 4. A grain that tastes good.
_______ 5. The part of the individual grain within the seed coat.
_______ 6. An offspring from genetically different parents.
_______ 7. A highly poisonous substance caused by the fungi Aspergillus florus
in grain.
_______ 8. The female reproductive part of the maize plant.
Part Two: Completion
Instructions. Provide the word or words to complete the following statements.
1. __________ __________ is the number of plants growing in one hectare.
2. __________ __________ __________ is a pest management strategy that
uses a combination of measures to reduce pest damage with the least
disruption to the environment.
3. A __________ __________ __________ is a measure of the temperature
requirements for best maize growth.
Part Three: Short Answer
Instructions. Provide information to answer the following questions.
1. Identify the parts of a grain seed.
2. Identify the parts of a mature maize plant.
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TM: D2-1
Real look at parts of a Kernel
Cotyledon – part of the
embryo that eats the
endosperm
Embryo
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TM: D2-2
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TM: D2-3
MOST COMMON TYPES
OF CORN
• Dent Corn—Zea mays indenta
• Flint Corn—Zea mays indurata
• Flour Corn—Zea mays amylacea
• Popcorn—Zea mays everta
• Sweet Corn—Zea mays saccharata
• Pod Corn—Zea mays tunicata
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LS: D2-1
Name_____________________________________
Lab Sheet
Maize Dissection
Materials Needed:
 Dry maize seed
 Wet maize seed
 Magnifying lens
 Razor blade or scissors
Procedure:
1. Look at the exterior of the dry and soaked maize seed.
2. Draw observations on this lab sheet below
3. Remove the seed coat of the soaked maize seed carefully.
4. Remove the seed coat of the dry maize seed.
5. Use a razor blade to split the seed carefully.
6. Use the lenses to try to locate the embryo (small plant) inside the seed.
7. Draw the inside of the seed including the embryo, endosperm, cotyledon, and seed coat
on the monocot handout. You may need to use TM:D2-1 as an aid.
8. Answer the questions below
Observation drawings (with labels):
What did you observe in both seeds that have been split into two parts?
Why is there an embryo in every seed?
What importance are seeds for us economically?
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LS: D2-2
Name_____________________________________
Lab Sheet
Calculating Growing Degree Days
Instructions:
Use the following formula and example to help calculate the growing degree day
problems.
Show all your work! Don’t forget that 10 is a constant 30° C is the maximum highest
temperature figured.
1. Low temperature = 11.1° C, high temperature = 31.1° C
2. Low temperature = 14.4° C, high temperature = 26.7° C
3. Low temperature = 10° C, high temperature = 27.8° C
4. Low temperature = 24.4° C, high temperature = 34.4° C
5. Low temperature = 26.7° C, high temperature = 40° C
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