Maize: cereal with a variety of uses
Khawar Jabran, Dr Zahid Ata & Dr Muhammad Farooq
ranks third most grown crop in the world with an area of
more than 118 million hectares with an annual production
of about 600 million metric tones. In Pakistan, maize is
the fourth largest grown crop after wheat, cotton and
rice. The area under maize here is over one million
hectare and production 3.5 million metric tonnes.
Punjab contributes 39 per cent of the total area under
maize and 30 per cent of total production; NWFP
contributes 56 per cent of the total area and 63 per
cent of the production while five per cent of the total
area and three per cent of the total production is
contributed by Sindh and Balochistan.
Maize has a variety of uses. Its grain is a rich source
of starch, vitamins, proteins and minerals. One hundred
gram of fresh grain contains 361 calories of energy, 9.4
g protein; 4.3g fat, 74.4g carbohydrate, 1.8g fibre;
1.3g ash, 10.6 per cent water, 140mg vitamins, 9mg
calcium, 290mg, phosphorus and 2.5mg iron.
In the green state, maize can be parched, baked,
roasted, boiled or steamed on the cob. Maize flour has a
very mild flavour and is used for making breads and as a
thickening agent in foods such as custards and jellies.
Popcorn is kernels of certain maize that burst when
heated, forming fluffy pieces that are eaten as a snack.
The starch extracted from maize grain is used in making
confectionery and noodles. Corn syrup from maize
contains high fructose and act as sweetener and retains
moisture when added to certain foods. Edible oil is
extracted from maize seeds, which is an all-purpose
Levulinic acid, a chemical derived from maize, is used
as ingredient in antifreeze and is capable of replacing
the toxic petroleum-based ingredients in use. Plastics
and fabrics are made from corn stocks.
Ethanol obtained from maize can be used as a biomass
fuel. Stigmas from female corn flowers, known as corn
silk, can be used as herbal supplements. Maize straw is
a cheap source of energy and can be used in home-heating
Maize can be used as forage, feed for livestock and
making silage after fermentation of corn stocks. Maize
is used extensively as the main source of calories in
animal feeding and feed formulation. Maize gives the
highest conversion of dry substance to meat, milk and
eggs compared to other cereal grains. Maize is a
valuable feed grain, because it is among the highest in
net energy content and lowest in protein and fibre
content. Animals like and eat it readily.
The maize hybrids possess capability of producing more
than 12 tones grains per hectare which is very high as
compared with 3.48 tones per hectare, the average yield
of maize in Pakistan. Important hybrids available in
Pakistan include High corn-8288, NK-8001, X-2276,
Monsanto-6525, Monsanto-919, Pioneer-3335, YHD-555 and
FSH-523. The gap between the realised and potential
yields can be bridged up by adopting suitable agronomic
practices and minimising the biotic and a biotic
stresses on the crop.
Soil and Climate: Maize is adapted to wide variety of
soil and climate and can be grown from coastal areas to
high altitude. Maize required a temperature of more than
10 0C to flower. Soils with a pH range of 6.5-7.5 are
most favourable. Well drained, heavy soils with high
organic matter content and good water holding capacity
give high produce.
Seed bed preparation, Sowing dates and Sowing Method:
Favourable conditions for germination and seedling
establishment are the important objectives of seed bed
preparation. Fine and compact bed is needed for maize.
The land with optimum moisture after rainfall or
irrigation is loosened 20-25 cm deep through ploughing
or disking 2-3 times, immediately followed by planking.
In Pakistan, maize crop is sown mainly in two seasons;
spring and the autumn season. Spring maize can be
planted in the first week of February up to first week
of March while the sowing time for autumn maize starts
from the last week of July and ends in mid of August.
Seed rate for maize is 20-25 kg per hectare. Seed is
dressed with some systemic insecticide, for example
imidacloprid at the rate of 1g per kg of seed.
Maize can be sown on both flat soils as well as on the
ridges. Ridge sowing is better for water saving. Ridges
are made 75 cm apart with a tractor drawn ridger. Choka
method or manual sowing is practiced for ridge sowing.
In case of flat sowing, maize is sown with automatic
tractor drawn drill or manual/hand drill with 75 cm
distance between the rows. Thinning is done after 10-15
days of emergence, consisting pulling out or cutting the
weak plants and maintaining a plant to plant distance of
20-25 cm. A plant population of 70,000 to 75,000 per
hectare is inevitable to harvest optimal yields.
Fertilizer: Fertiliser rate for maize is 150-100-100 kg
nitrogen, phosphorous and potassium per hectare
respectively. All phosphorus and potassium while half
nitrogen are side dressed with sown seed rows while the
remaining half N is added to soil in 2 splits, first
when the crop is at knee height and second at tasseling.
Plant Protection Measures: Immediately after emergence,
maize crop faces a serious threat of shoot fly and stem
borer attack. Stem borer bores into the stem and makes a
hole in the stem. Furadan powder should be dropped into
the shoots or broadcast at the rate of 20 kg ha-1
followed by irrigation. This practice should be repeated
twice at 1-2 week interval.
Weeds reduce maize yield by 29-43 per cent or even more.
Competition of weeds with maize plants is maximum 2-5
weeks after crop emergence. The most common weeds of
maize in Pakistan include purple nutsedge (deela),
horsepurslane (itsit), slender amaranth (jangli chulai),
digera (tandla), jungle rice (jangli swank), burclover
(maina) and swine cress (jangli haloon).
Common herbicides effective to control these weeds
include Primextra Gold at 800 mL per acre, Pendimethalin
at 1300 mL per acre and Dewal Dold at 800 mL per acre
used as pre-emergence to weeds. While atrazine at 350 mL
can be used as early post emergence 15 days after weeds
emergence. A hand hoeing about 25 days after sowing
provides satisfactory weed control at small scale.
Irrigation: Maize is drought sensitive crop and requires
frequent irrigations for successful vegetative and
reproductive growth. An irrigation within 10-15 days
interval results in good growth. Drought will restrict
many physiological processes leading to reduced yields.
Moisture stress at critical stages i.e. flowering,
fertilisation or milking may cause a yield reduction up
to 40 per cent due to reduction in number of grains per
cob. Total number of irrigations for maize may vary from
6-9 depending on climate, soil type and method of
Harvest and Post Harvest: Maize crop is harvested when
the moisture content of the grains are 20-25 per cent.
The cob sheath dries completely at this stage, some
drying may occur on the stalk. Cobs are removed from
standing crop and dried under sunlight until the
moisture content of the grains is below 15 per cent.
Hand operated or powered maize shellers are better than
manual or hand shelling for safe exclusion of dried
maize grains from cobs. Shelled maize grains after
cleaning are stored in jute sacks in a cool, dry and
airy place, either on a cement floor or on wooden
planks; it should not be stored on earthen floors. The
temperature of store room is kept 20-25 0C while
relative humidity is maintained at 30-50 per cent.
Maize has prospective to play major role in nutrition of
Pakistani people. It can act as the alternate food
source when the conventional cereal grains i.e. wheat
and rice are deficient.
Courtesy: The DAWN