INTRODUCTION OF MAIZE

Maize or the scientific name Zea mays and also the common name corn is the third most

important grain worldwide, after wheat and rice. It is generally believed that the earliest form of

maize arose from natural hybridization of two or three grasses native to Mexico and Guatemala.

Scientific classification

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AGRONOMY OF MAIZE

What is the agronomy??

Agronomy is the science and technology of producing and using plants for food, fuel, fiber,

and reclamation. Agronomy includes work in the areas of, plant physiology, plant genetics

meteorology, and soil science. Agronomy is the application of a combination of sciences like

biology, chemistry, economics, ecology, earth science, and genetics. Agronomists today are

involved with many issues including producing food, creating healthier food, managing

environmental impact of agriculture, and creating energy from plants. Agronomists often

specialize in areas such as crop rotation, irrigation and drainage, plant breeding, plant

physiology, soil classification, soil fertility, weed control, insect and pest control.

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Kingdom: Plantae

(unranked): Commelinids

Order: Poales

Family: Poaceae

Subfamily: Panicoideae

Tribe: Andropogoneae

Genus: Zea

Species: Z. mays

AGRONOMY OF MAIZE

Agronomy of maize consists of cultivars, plant population, soil tillage, fertilisation, weed,

insect and disease control, harvesting, how to cultivate maize, maize planting, quality seed

production in maize hybrids and treatment to maize diseases.

How to cultivate the maize?

The highest weight of maize crop production have found that as compared to rice and wheat.

Maize in the spring crop planting is done that this season of rain may reap. Rain for the crops, so

much as Maize is sensitive to drought are important. Generally, one two or three crops the crop

cultivation is in the rotation.

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An agronomist field sampling a trial plot of flax.

An agronomist mapping a plant genome.

MAIZE CULTIVATION

Maize thrives best in a warm climate and is now grown in most of the countries that have

suitable climatic conditions. Its growth depends more on high summer temperatures than on a

high mean temperature. It will ripen in a short hot summer and will withstand extreme heat. A

large amount of water is needed during the growth of the maize. Its average maturing period is

relatively short and this makes it possible to grow at fairly high latitudes.

In the United States of America, the maize growing area stretches from approximately 40

degrees South to 45 degrees North. In Europe, maize growing reaches as far North as 46 degrees

on the West coast of France. From this point, the line runs across Europe reaching 50 degrees in

the East before falling, only to rise again in Southern Russia approaching 52 degrees.

The U.S.A. has the highest output of maize amongst the countries involved in maize growing. In

1964 it produced more than half of the total world maize growth, accounting for 104 million tons

grown by the nation. Today the world harvests almost as much maize as wheat.

Maize is exceptional in yield per unit area. The harvest may vary from 2.5 to 6 tons per acre

according to the soil and its cultivation. Yields above 7 tons per acre have often been recorded.

Cultivation of maize in the following steps :

Planting :

crop sowing when the crop is planted. In mid-April planting of maize normally is used

for mid-May.

Silking :

crop cultivation is the most crucial stage. This means crop pollination.

Doughing :

When maize crop starts to show a thick substance, called crop will doughed.

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Denting :

doughing During the process, like plant material in the formation of the dough spends all

its resources and to reduce the plant and 'one' break begins at end of matter is to show .

The denting thus called.

Maturing :

When the green leaves of maize leaves and is gone from opening appears, the crop is said

to be mature.

Collection :

crop generally is mature around 3 -4 months end and then it is ready to be collected or

harvested.

TYPES OF MAIZE

There are about 50 different species of maize having their own characteristic features and kernel

sizes, all belonging to a small number of types. Colour and structure, as well as the shape of the

kernel, differ from one species to another.

White, Red and Yellow are the most common basic colours of maize, but it is possible to find a

wide range of shades, from Red-Brown to Light Red and from a Pale Yellow to Orange.

The shape of the kernel can be divided into two main groups:

Maize Shape Texture

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Flint maize (round shape) Dent maize (tooth shaped)

White Flint or Dent Varies

Plata Flint Hard, Glassy

Yellow Mostly Dent Comparatively Soft

In general, the flint glassy-kernel varieties yield better grits than the softer mealy dent maize.

Some products, however, require a raw material of the soft type. For milling purposes the maize

should be dry and bright. Dull colour often indicates that the maize is old or has been harvested

or stored under unfavourable conditions. The germ must be free of mould.

Great importance is attached to the use of sound and fresh grain to give high quality in finished

products. The quality of the maize affects the yield and fat content of the grits or flour much

more than in wheat milling. Different types and qualities of maize undergoing identical grinding

operations will produce grits or flours which vary considerably.

TYPICAL COMPOSITION

Endosperm   82%

Germ     12%

Bran   5%

Tip Cap 1%

Total: 100%

TYPICAL ANALYSIS

Components  % % Dry Basis

Moisture 9 – 15 --

Starch 61 72

Protein   8.5 10

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Fibre  9.5 11

Oil 4 3.4 – 5

Ash -- 1.6

QUALITY SEED PRODUCTION IN MAIZE

HYBRIDS

Suitable climate

In Tamil Nadu, maize is cultivated during June – July, September – October and January

– February seasons. Sowing during November - December is suitable for seed

production, since seed maturity stage will not coincide with rainfall.

Isolation distance

For this isolate the hybrid seed crop from fields of other maize varieties with same seed

color by 200 m distance.

Land requirement

Well drained sandy red or black soil is suitable. The selected fields should be free from

volunteer maize plants.

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Seed treatment

To control the fungal disease treat the seed with thiram at 2g kg-1 seed. One day after

treat the seeds with 600 g of Azospirillum with rice gruel and shade dry for 15 minutes.

GROWTH AND DEVELOPMENT

Growth stage 0: from planting to see emergence

During germination, the growth point and the entire stem are about 25 to 40 mm below

the soil surface. Under warm, moist conditions seedlings emerge after about six to 10

days, but under cool or dry conditions this may take two weeks or longer. The optimum

temperature range for germination is between 20 and 30 ºC, while optimum moisture

content of the soil should be approximately 60 % of soil capacity.

Growth stage 1: four leaves completely unfolded

The maximum number of leaves and lateral shoots is predetermined and a new leaf

unfolds more or less every third day. The growth point at this stage is still below the soil

surface and aerial parts are limited to the leaf sheath and blades. Initiation of tasselling

also occurs at this stage.

Growth stage 2: eight leaves completely unfolded

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During this period, leaf area increases five to 10 times, while stem mass increases 50 to

100 times. Ear initiation has already commenced. Tillers begin to develop from nodes

below the soil surface. The growth point at this stage is approximately 5,0 to 7,5 cm

above the soil surface.

Growth stage 3: twelve leaves completely unfolded

The tassel in the growth point begins to develop rapidly. Lateral shoots bearing cobs

develop rapidly from the sixth to eighth nodes above the soil surface and the potential

number of seed buds of the ear has already been determined.

Growth stage 4: sixteen leaves completely unfolded

The stem lengthens rapidly and the tassel is almost fully developed. Silks begin to

develop and lengthen from the base of the upper ear.

Growth stage 5: silk appearance an pollen shedding

All leaves are completely unfolded and the tassel has been visible for two to three days.

The lateral shoot bearing the main ear as well as bracts has almost reached maturity. At

this point demand for nutrients and water is high.

Growth stage 6: green mealie stage

The ear, lateral shoot and bracts are fully developed and starch begins to accumulate in

the endosperm.

Growth stage 7: soft dough stage

Grain mass continues to increase and sugars are converted into starch.

Growth stage 8: hard dough stage

Sugars in the kernel disappear rapidly. Starch accumulates in the crown of the kernel and

extends downwards.

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Growth stage 9: physiological maturity

When the kernel has reached its maximum dry mass, a layer of black cells develops at the

kernel base. Grains are physiologically mature and only the moisture content must be

reduced.

Growth stage 10: drying of kernel (biological maturity)

Although grains have reached physiological maturity, they must dry out before reaching

biological maturity. Under favourable conditions, drying takes place at approximately 5

% per week up to the 20 % level, after which there is a slowdown.

ADAPTATION AND PRODUCTION POTENTIAL

Temperature requirement -Maize is a warm weather crop and is not grown in areas

where the mean daily temperature is less than 19 ºC or where the mean of the summer

months is less than 23 ºC.

Water - Approximately 10 to 16 kg of grain are produced for every millimetre of water

used. A yield of 3 152 kg/ha requires between 350 and 450 mm of rain per annum. At

maturity, each plant will have used 250 l of water in the absence of moisture stress.

Soil requirements - The most suitable soil for maize is one with a good effective depth,

favourable morphological properties, good internal drainage, an optimal moisture regime,

sufficient and balanced quantities of plant nutrients and chemical properties that are

favourable specifically for maize production.

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MAIZE HARVESTING PROCESS

Harvest time

The optimum time of harvesting maize is when the stalks have dried and moisture of

grain as about 20-17%.

Harvesting process requirement

Harvest maize as soon as it is dry but not overstay in field it will be attacked by weevils if

does and lodge. In addition to reducing post harvest losses, this will also release the field

for early land preparation.

Keep the grain as clean as possible. Dry maize on cement floor or use tarpaulin to reduce

chance of contamination.

At home, do not first heap the cobs in any room, kitchen or in the yard because this will

expose them to all the dangers that cause post harvest losses. Transfer them to the drying

place (like the crib) immediately.

Dry on concrete or canvas not on bare soil.

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Before Harvesting

Make sure the drying place or equipment is clean and disinfected, ready to receive the

cobs.

Remove old grain and dirt from anything that will come in contact with the good or new

grain. This includes harvesting tools, carts, wheel barrows, bags and baskets.

Where possible, fumigate them or at least treat them with boiling water to kill insects or

their eggs. This is done in order to avoid infection of new grain by insects and their eggs.

Organize enough labour to reap and carry the cobs to the drying place.

After Harvesting

Drying- the systematic reduction of crop moisture down to safe levels for storage,

usually 12%-15.5% moisture content. It is one of the key post harvest operations since all

down-stream operations depend on it.

Shelling- Shelling is commonly done by beating maize cobs with stick in a sack or a

confined floor space where farmers can afford it.

Storage- to maintain the stored grains in good condition so as to avoid deterioration both

in quantity and quality.

Spillage

Losses due to poor storage

Mould

Microbial infection in storage occurs due to inadequate drying of produce. The situation

is made worse when there are large numbers of insects present or when the stored crop is

exposed to high humidity or actual wetting due to poor storage management. Fungal

infection results into rots and development of aflatoxins, which are poisonous compounds

to live stock and cause cancer in human.

Conditions that favour aflatoxin contamination in maize grains

Aflatoxin contamination is encouraged by:

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Physical damage due to poor shelling/threshing methods

Poor storage methods (exposure to moist condition)

Insect infestations.

Inadequate drying

Aflatoxin cannot be seen with a naked eye. However, suspect materials tend to:

Be rotten

Be mouldy

Be discoloured

Have unpleasant smell

Have bitter taste

Have poor milling quality

Be warmer than room temperature.

Losses due to mould

Loss of weight

Loss of quality (smell, taste, colour, nutritional value, germination)

Further increase in temperature and moisture, causing more grain deterioration.

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SOIL TILLAGE

Soil tillage, particularly primary tillage, is the foundation of any crop production system

and is the biggest cost factor in maize production.

Primary tillage implements

Mouldboard ploughs - This implement is used to turn sods up to 300 mm depth and is

particularly useful on heavier well-structured soils. Turning the soil also has the

advantage that weed seeds and unwanted crop residues can be buried deeply. Mouldboard

ploughs are not recommended on sandy soils, because poorly-structured units which may

exist, can be destroyed and wind erosion be promoted.

Disc ploughs and discs - The disc plough has a slicing action with the main advantage

that better penetration is obtained under dry, hard conditions, with an additional

advantage that wear is lower than in the case of a mouldboard plough. The implement is

useful on hard, dry soils where loss of structure is not too critical. It is on no account

recommended for sandy soils.

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Chisel ploughs - Chisel ploughs are used mainly to loosen the soil to a limited depth of

250 mm. Best results are obtained if the soil is relatively dry, because the chisels break

the soil, creating structural units. If conditions are too dry, however, big clods are formed,

restricting plant development.

Rippers - Rippers are used when deep cultivation is necessary and turning of the soil is

undesirable. If soils are tilled annually to the same depth, a plough-sole develops. This

confined layer prevents infiltration and root development. To ensure better drainage,

conservation and utilisation of water, it is essential to break this layer regularly. Under

wet, clay conditions, the main disadvantage of the ripper is that it compacts the soil

laterally and inwards, which can limit lateral root development.

Secondary tillage implements

Rotary tiller - Under ideal conditions, on moist clay soils, this useful implement can

prepare the seedbed in one operation. On dry, sandy soils it can, however, destroy the

structure within a very short period.

Tined cultivators - Tined cultivators include a variety of hoeing implements, which are

used mainly for controlling young weeds, but also utilised for breaking surface crusts.

These implements are only effective on moist soils. They are completely ineffective on

dry, clay soils. These implements are often used for seedbed preparation.

Harrows - Harrows include a variety of implements. The tined harrow is primarily used

to level the seedbed once it is in a fine condition. The primary objective of the disc

harrow is to break surface crusts, but it can be used to break clods to obtain a fine

seedbed.

Tillage systems

No-till

With this system, soil is left undisturbed from planting to harvesting. A prerequisite for

this type of cultivation is that 30 % of the soil must be covered with plant residue after

planting to reduce water erosion effectively.

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Stubble-mulch tillage

In this case, soil is disturbed before planting without burying or destroying. For this

action chisel ploughs, discs, spring-tooth implements or V-type blades are used. Weeds

are controlled chemically and/or mechanically.

Reduced tillage

This could be any type of tillage practice which leaves 15 to 30 % of the soil surface

covered with stubble. Weeds are controlled chemically or mechanically.

Conventional tillage

This includes tillage that leaves less than 15 % of the soil surface covered with stubble.

Conventional tillage usually implies a plough action or an intensive range of cultivations.

It is important to bear in mind that 1 ton of grain/hadelivers one ton of plant residue,

which is sufficient to cover 10 % of the soil. If conservation tillage is considered as an

alternative, a minimum yield of 3,0 ton/ha must be obtained to provide a surface cover of

30 %. When conservation tillage is practised with the aim of conserving moisture, at least

50 to 60 % of the soil surface should be covered. With any tillage system, it is paramount

importance to ensure that a compacted layer, that may impair plant growth, does not

occur in the effective root zone. Any soil has the potential to form a compacted layer and

therefore all cultivated soils should be inspected regularly for such restrictions. If

confined layer is detected, it should be broken using a ripper implement to ensure better

drainage, conservation and utilisation of water.

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PEST AND DISEASES OF MAIZE

EARTHWORMS

This ugly caterpillar can grow to 2 inches and comes in shades of green, pale yellow and

brown. Adults are dull beige or gray moths with a 1½ inch wingspan and a few black

spots. They begin munching the tender shoots as soon as they break ground. They chew

tassels and interrupt pollination and kernel development. Inside the ears they will

consume kernels and leave globs of fecal material.

CUTWORMS

This is a catchall name for the destructive larvae of hundreds of different species of

moths. They are soft, ugly, fat, bristly and of almost any color. Some species climb into

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plants to feed, but the classic sing of busy cutworms is seedlings gnawed at the base until

they fall over. Most damage is done at night.

APHIDS

Tiny (less than 1/10 inch) soft bodied pear shaped insects with whiplike antennae. Varied

in color. Leaves turn yellow.

BIRDS

Some birds are nice to have around the garden because they eat insect pests. Others, such

as crows and blackbirds, can be destructive.

SOLUTION FOR THE PESTS

PESTS SOLUTION

Earworms Fall and spring tilling helps by exposing the pupae to

wind, weather, and predators. Early plantings of corn may

avoid damage and cold, damp weather discourages

earworms almost as much as it does the corn.

Corn varieties with tight husks are physically more

resistant to earworm damage. Try Country Gentleman or

Silver Cross Bantam. Clipping a clothespin on the tip of

each ear can help to keep husks tight.

Wormwood Spray or a spray made from garlic and onion

tea.

A drop of mineral oil on the tip of each ear may help to

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suffocate any resident earworms. Give the mineral oil by

mixing with pureed African marigolds or geranium leaves.

Do not apply mineral oil until pollination is complete.

Check the farm supply store to see what insect predators

are available.

Blacklight traps will destroy earworms, and cosmos,

smartweed and sunflowers are good trap crops.

Cutworm Till soil as early as it can be worked in the spring and

allow 2 weeks. This removes weed seedlings that the first

wave of larvae depend on for food. Eggs are laid in weeds

and grass. Keep the garden clean. 

Interplant with onion, garlic or tansy to repel cutworms or

plant sunflowers as a trap crop.

Handpicking is easiest and most productive following a

rain or thorough watering and should be done after dark.

Cutworms can be spotted with a flashlight.

Placing a cardboard collar around young seedlings

presents a barrier that cutworms can't cross. Use a piece of

a toilet paper or paper towel roll or a paper cup with the

bottom torn out.

Cutworms love cornmeal, but they can't digest it. The

cornmeal can be cut with Bt  for a fatal feast.

Molasses mixed with hardwood sawdust is an effective

trap when spread around susceptible plants. The cutworms

will get stuck in the molasses and can be destroyed in the

morning.

Adult moths are easily killed with bug zappers.

Aphids Plant alliums such as garlic and chives. Anise, coriander,

nasturtiums, and petunias may be helpful. Use yellow

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sticky traps or yellow dishes containing soapy water.

Soap-Shield and mint tea spray is highly effective.

Lacewings will eat 100 aphids per day

Birds Use netting over the corn row. When harvest approaches,

use net bags over corn ears. Orange and onion bags will

do nicely.

DISEASE MANAGEMENT OF MAIZE

DISEASE EPIDEMIOLOGY

Black Bundle Disease and

Late Wilt: Cephalosporium

maydis, Caphalosporium

acremonium

The disease kills the plant prematurely after flowering.

Infected plants do not show symptoms until they reach to

tasseling.

Wilting generally starts from the top leaves, Leaves

become dull green, eventually loose colour and become

dry.

In advance stages the stalk loses its healthy green colour,

lower portions become dry,shrunken with or without

wrinklings, hardens and turn purple to dark brown which

in more prominent on lower internodes.

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When split open diseased stalks, show brown vascular

bundles starting in the underground portion of the roots.

Diseased plants produce only ears with undeveloped

shrunken kernels.

In severe cases affected plants remain abortive causing

100 per cent loss.

Cephalosporium maydis is primarily soil borne and may

infect young maize plants more readily than other plants

through roots or mesocotyl. In case of C.

acremonium only vascular burdles get blackened.

Bacterial Stalk Rot: Erwinia

carotovora, Erwinia

chrysanthemi

High humidity especially overhead irrigation and

waterloging, coupled with high temperature (30oC and

above), are conducive for disease development.

The basal internodes develop soft rot and give a water

soaked appearance. A mild sweet fermenting odour

accompanies such rotting.

Leaves some time show signs of wilting or water loss and

affected plants within a few days of infection lodge or

topple down.

Ears and shank may also show rot. They fail to develop

further and the ears hang down simply from the plant

Charcoal-

Rot : Macrophamina

phaseolina

The disease development is maximum during grain filling

stage and is favoured by warm temperature (30-400C) and

low soil moisture.

Charcoal rot is found to be prevalent particularly

in rabi season when summer temperatures during post

flowering period becomes comparatively high (35 -

450C).

Disease cycle

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The pathogen also attack many other hosts, which helps

in its perpetuation. Since the fungus is a facultative

parasite it is capable of living saprophytically on dead

organic tissues, particularly many of its natural hosts

producing sclerotial bodies.

The fungus over winter as a sclerotia in the soil and

infects the host at susceptible crop stage through roots

and proceed towards stem.

Common Rust : Puccinia

sorghi

Cold temperature (16-23°C) and higher relative humidity

favor the rust development and spread

Downy Mildews Downy mildews are an exciting group of fungi which

attacks many economically important crop plants.

Ten downy mildew diseases are known on maize caused

by two genera viz., Peronosclerospora and Sclerophthera.

Out of these, Sorghum Downy Mildew and Brown stripe

downy mildew are common in our country.

CONCLUSION

Maize is essentially a crop of subtropical regions, but after selecting and breeding, a large

number of cultivars are now also adapted to temperate conditions. However maize has the

characteristic C4 cycle photosynthetic development, which means vigorous growth and high

yields under warm and bright conditions. Maize does not thrive well in semi arid or equatorial

climates. For germination the minimum soil temperature has to be 10o C. for growth and

development the average day temperature should be at least 15o C. It is easily killed by frost.

Maize grows on a wide range of soil types, but prefers deep, naturally rich, easily tilled soil, pH

5.5-6, it is sensitive to salinity. Maize is rather drought-tolerant, however, annual rainfall of at

least 750nm is required for adequate moisture, especially around the time of tasseling and

fertilization, maize plants are very sensitive to water deficiency.

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Maize is nearly always planted through direct seeding. Soil temperature has to be about 10oC,

below that temperature the seeds do not germinate until the desired soil temperature is reached. If

that takes too much time, soil pathogens can cause damage to the seeds. The result may be that

the seeds do not germinate at all or produce abnormal seedlings. Plant density depends on

cultivars,cropping system and cropping purpose( for silage, higher density than for the grain),

soil condition and climate, it ranges from 20000 to 100000 plants/ha. Sowing has to be done

carefully because maize has poor tillering capacity, it is mostly not able to fill open spaces in the

field. The seeds have to be placed 2.5-6 cm deep, depending on how deep the moist soil is

located below the dry surface layer.

Maize usually responds well to fertilizer. Each produced tonne of grain removes about 30kg

N, 5kg P and 35kg K. How much fertilizer has to be applieds depends on inherent soil fertility.

Modern hybrids only reach their high yield potential when sufficient nutrients are applied. Weed

control will be necessary, especially in the juvenile stage.

REFERENCES

1. Ton Elzebroek and Koop Wind (2008) Guide to Cultivated Plants, CAB

International (326-327)

2. Rick Hodges & Graham Farrell (2004) Crop Post-Harvest : Science and

Technology Volume 2 DURABLES, Blackwell Publishing (26-51)

3. R.B.H Wills (2007) Postharvest,. An introduction to the physiology and handling

of fruit, vegetables and ornamentals, CAB International (99)

4. http://en.wikipedia.org/wiki/Maize

5. www.Ikisan.com/maize

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6. http://nigeria.thebeehive.org/

7. http://www.gardenguides.com/

8. http://agropedia.iitk.ac.in/

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