Maize (Revised)

General Information and Agronomic Aspects

Introduction

Zea mays, commonly known as maize or corn, is a staple cereal crop that holds immense importance worldwide. It belongs to the family Poaceae (grass family) and the genus Zea. The genus Zea comprises 5 distinct species, with Zea mays being the most well-known and extensively cultivated. The other 4 species are wild perennial relatives and include Z. diploperennis, Z. luxurians, Z. nicaraguensis and Z. perennis. Zea mays is a remarkably diverse species, and its cultivars can be classified into distinct types or cultivar groups, including Dent corn, Sweet corn, Flint corn, Popcorn, Pod corn, and Flour corn. Each of these types possess unique characteristics and serve specific purposes.

Maize is the most important cereal crop in sub-Saharan Africa, serving as a staple food for an estimated 50% of the population. Maize is a versatile crop primarily grown for its edible kernels, which can be used fresh, dried or processed into various products such as cornmeal, corn coil and corn syrup.
Maize plays diverse roles in African diets, featuring in meals like maize meal, porridges, pastes and beer. Green maize, fresh on the cob, is eaten baked, roasted or boiled. Every part of the maize plant has economic value: the grain, leaves, stalk, tassel, and cob can all be used to produce a large variety of food and non-food products.

In sub-Saharan Africa maize is mostly grown by small-scale farmers, generally for subsistence as part of mixed agricultural systems. The systems often lack inputs such as fertiliser, improved seed, irrigation, and labour.  According to FAO data, Africa produced 7.4% of the 1, 135 million tonnes produced worldwide in 40 million hectares in 2017 (FAOSTAT, 2017). Popcorns are freshly popped snack foods.
Maize is a valuable source of carbohydrates, dietary fiber, vitamins (such as B vitamins), and minerals (such as magnesium and phosphorus). It is low in fat and protein.
Every part of the maize plant, from the grain to the leaves, stalk, tassel, and cob, holds economic value. These components can be harnessed to produce a wide array of both food and non-food products and animal feed. Maize is also vital in industrial applications like ethanol and biofuel production, as well as the manufacturing of products such as oil and plastics.
In sub-Saharan Africa maize is mostly grown by small-scale farmers, generally for subsistence as part of mixed agricultural systems. The systems often lack inputs such as fertilizer, improved seed, irrigation, and labour. Key maize-producing countries in the world encompass the United States, China, Brazil, Argentina and India.
(Apraku & Fakorede, 2006, PROSEA, 2016, FAOSTAT, 2017, 2021)

Species account

Zea mays is a monoecious, annual plant that grows to a height of 2 to 4 m, or even taller depending on the variety and growing conditions. Stems: cylindrical, solid often jointed with nodes and internodes where leaves are attached. Leaves: alternate and arranged in a spiral pattern around the stem, long, flat with parallel venation with a prominent midrib. Inflorescence: composed of separated male and female flowers arranged in the “ear”. Male and female inflorescences separate on the same plant. Male flowers are born on the tassel located at the top of the plant, Female flowers are found on the cob. Tassels: male inflorescence consists of spikelets each containing stamens with pollen producing anthers. As tassel mature, it releases pollen into the air which is carried to the female inflorescence. Seeds (Kernels): can vary in color (yellow, white, red, grey etc) and size depending on the maize variety. 
(Apraku & Fakorede, 2006, PROSEA, 2016).

Zea mays is a varied species and can be further divided into 7 major cultivar groups based on the grain starch, appearance, and end uses.
•    Dent corn (Z. mays var. indentata)- this cultivar group derives its name from the dent or depression visible on the dried matured kernel; the wedge-shaped grains are usually yellow or white; it is the principal maize in Mexico, Central America, the Caribbean, and southern Africa.
•    Sweet corn (Z. mays convar. saccharata var. rugosa)), the seed has a shiny endosperm with low starch content, resulting in a wrinkled look when dried. Typically consumed when young as a fresh vegetable, it's mainly cultivated in the USA but has become popular among affluent individuals in African nations.
•    Flint corn (Z. mays var. indurata) recognized for its hard exterior layer; ranges in color from white to deep red. Flint corn thrives in cool climates with wetter soil and generally performs better at higher altitudes. It matures earlier than other varietals of maize. Flints also store more durably than other varietals because the kernels absorb less moisture and are more resistant to fungi and insects. It's often used for grinding into cornmeal and other industrial applications.
•    Popcorn (Z. mays var. everta) small grains with a high proportion of very hard corneous endosperm and a little soft starch in the center; pops when heated due to internal pressure buildup, the endosperm becoming everted about the embryo and hull to produce a palatable white fluffy mas. It's a popular snack and is cultivated for this unique characteristic. most important in the United States and Mexico.
•    Pod corn (Z. mays var tunicata) It is the earliest domesticated maize and showcases unusual kernels enclosed in husks, resembling a pod-like structure. It is not grown commercially.
•    Flour corn (Z. mays var. amylacea) valued for its high starch content, making it suitable for grinding into flour. It has culinary and industrial applications.
Among the different kinds of grains, numerous varieties are cultivated in various regions across the globe.
(Apraku & Fakorede, 2006, PROSEA, 2016).

Maize Varieties

Types of Varieties
Open Pollinated Variety (OPV): Open Pollinated Varieties or composite (e.g. "Katumani", "Coast Composite") are stabilized varieties in which farmers do not need new seed each year. If farmers follow proper selection procedures, they can use their seeds selected from their harvests up to three seasons after which they can buy fresh seeds from seed companies. However, yields of OPV are lower than hybrids.
Local Seeds: Low to medium yields, usually well sheathed and so more resistant to weevil attack in storage (most are of flint type) and more palatable to local tastes. Example: Kikuyu and Kikamba maize. New exotic varieties of maize can be collected to add genetic diversity when selectively breeding new domestic strains.
Hybrid: Hybrids are high yielding but also requiring large amounts of fertilizer and other inputs. They are often bred for specific ecological zones or for other reasons including pest and disease tolerance. Unfortunately new certified seeds should be purchased every season which is a financial strain for poor farmers. 

Seed Selection and Treatment
Maize variety selection depends on:
i.    Yield Potential: Evaluate the variety's yield potential to ensure it meets your production goals.
ii.    Adaptability: Select varieties that can thrive in a variety of conditions, considering factors like tolerance to environmental stresses such as drought, heat, and frost.
iii.    End-use: Maize is primarily grown for grains, silage and stock feed. Ensure the variety you grow is suited to the end use market you are aiming for.
iv.    Maturity: Plan to sow seeds of chosen variety in the recommended planting windows outlined in Table 2, ensuring maturity, expected rainfall and expected harvest time (days to harvest) . It is also important to ensure harvest will not be far into the dry season as prolonged drought will encourage the onset of aflatoxin in maize.
v.      Stability: Select varieties that have well developed roots, strong stalks, and are resistant to root and stalk rot. These features help prevent the plant from falling over/logging, which can lower the yield and quality of the grain.
vi.    Insect and disease tolerance/resistance: Always select a maize variety that is known to have tolerance/resistance to a disease or insect pest common in your area where is to be grown so as to attain maximize yield potential.

Note: If you receive or acquire a new maize variety, then test it on small plots before scaling up the production to big plots. Observe and compare the performance of the new variety with the other varieties at every stage of growth under similar management conditions of planting time, weeding and soil fertility management. This will help you to choose the best performing variety under local prevailing conditions.

Some examples of maize varieties in Kenya
There are few pure varieties of maize at present because farmers tend to grow the more productive hybrids and composites. The Kenya Flat Complex is one of the low yielding varieties but has good sheathing which prevents damage by weevil when stored with husks on.
Several hybrids and composites are produces in various research stations like the National research Station - Kitale, Embu Research Station, Katumani Research Station Machakos and Coast Agricultural Research Station - Mtwapa.
Hybrids are bred by crossing inbreed lines or varieties under conditions of controlled pollution. Composites on the other hand are bred growing a number of varieties together under uncontrolled pollination, there is free inter pollination.
These hybrids and composites are produced for specific altitudes in the country. Some of these are Kitale hybrids for example 614, 622, 625, 626. 627, and 632. They are generally grown in medium to high altitude zones. Embu hybrids include 511 and 513, they grow best in medium altitude zones. Katumani composites have been developed for lower altitude zones. Coast composites, Pwani hybrid 1 and pwani hybrid 4 have been developed at the Coast Agricultural Research Station - Mtwapa for cost province. Others include double cob varieties for example DH01 and DH02.
The choice of appropriate maize varieties for a given location is very important because every variety has extensively been tested and recommended based on climatic conditions, soil type, yield potential, tolerance/resistance to pest and diseases or maturity period among others. 

Table 1: Maize Growing Zones in Kenya and Recommended Varieties

Variety	KALRO Maize variety	Year Released/Center/Scientist	Attributes	Uses	Where Grown	Commercialization By Who
H511		1967 Kenya Seed Co/KARI	Optimal production altitude range (Masl) 1000-1500 m Maturity: 4-5 months Grain yield (t ha-1 ) 4-7 Novelty: Medium maturity	Used to make maize flour, mixed with beans to make githeri or with cow peas for muthokoi, can be eaten as roasted or boiled maize whole on cob, livestock feed, corn oil	Western Kenya, Lake region, South Rift, Meru and Central	Kenya Seed Co/KARI
H622		1967 Kenya Seed Co/KARI	Optimal production altitude range (Masl) 1200-1700 m Maturity: 5-7 months Grain yield (t ha-1 ) 6-8 Novelty: Large kernels Dent	Used to make maize flour, mixed with beans to make githeri or with cow peas for muthokoi, can be eaten as roasted or boiled maize whole on cob, livestock feed, corn oil	Western Kenya, Lake region, South Rift, Meru and Central	Kenya Seed Co/KARI
H632		1967 Kenya Seed Co/KARI	Optimal production altitude range (Masl) 1200-1700 m Maturity: 5-7 months Grain yield (t ha-1 ) 6-8 Novelty: Large kernels Dent	Used to make maize flour, mixed with beans to make githeri or with cow peas for muthokoi, can be eaten as roasted or boiled maize whole on cob, livestock feed, corn oil	Western Kenya, Lake region, South Rift, Meru and Central	Kenya Seed Co/KARI

Source: KALRO-KCEP Technology Validation Report, 2016

 

Table 2: Maize Varieties in Kenya, their Ezo-Zones, Time it Takes to Mature and Their Yield Potential

Eco-zone and main areas where found.	Recommended varieties	Maturity (months)	Yield  potential (bags/ acre)
Highland zones with high rainfall; Altitude:15002100m above sea level; Areas: Trans Nzoia, Uasin Gishu, Nakuru, Kericho, Nandi, Bungoma, Laikipia, Kisii, Narok and Tea zones of Central and Eastern provinces.	H 627 H 626 H 625 H614D	6-8 6-8 6-8 6-9	42 38 34 32
Highland zones, high rainfall; Altitudes: 1000-1700m above sea level; Areas: Baringo, Siaya, Kisumu, Busia, Bungoma, Kakamega, Nakuru, South, Nyanza, Taita Taveta	H632, WE1101 H622	6-8 6-8	24 22
Coffee zone medium long growing season; Altitude: 1000-1800m above sea leave; Areas: Coffee zones of Central and Eastern provinces, Kisii, Narok, Nakuru, Siaya, Kisumu, Busia, Kakamega, Bungoma, West Pokot, Keiyo, Marakwet	H513 PHB3253 H511 Duma 43	4-5 4-5 4-5 4-5	20 20 16 18
Dryland areas. Marginal areas with low rainfall. (400mm-800mm); Altitude: 1000-1800 above sea level; Areas: Kitui, Machakos, West Pokot, Makueni, Kajiado, Isiolo, Lower Meru and Embu, Siaya, Kisumu	KCB, KDV 1, KDV 4 and KDV 6, Sungura, Sawa DH01 DH02	3-4 3-4 3-4	12 14 14
AItitude: 800 - 1200 m above sea level, Drier areas same as for Kitui, Machakos, Makueni drier areas.	DLC	3-4	11
Lowland zones - Hot humid; Altitude: 0-1200m above sea level	PH4 PH1	3-4 3-4	18 14

Source: KALRO-KCEP Technology Validation Report, 2016.

 

Table 3: Recommended Maize Varieties in the Western Kenya and Rift Valley Regions

Variety	Source	Agro - Ecological Zone where grown	Yield potential (90 kg bag/acre)
H 6218	Kenya Seed Company	Highlands	56
H 6213	Kenya Seed Company	Highlands	52
H 6210	Kenya Seed Company	Highlands	50
H614D	Kenya Seed Company	Highlands	33
H629	Kenya Seed Company	Highlands	35
H624	Kenya Seed Company	Highlands	35
H 517	Kenya Seed Company	Highlands	20
P 30G19	Pioneer Seed Company	Medium	30
SIMBA 61	Seedco Company	Medium	30
WH505	Western Seed Company	Medium	30

Source: KALRO-KCEP Technology Validation Report, 2016

 

Highland Maize Varieties: These varieties are bred and recommended for medium to high altitudes (1500-2400 m) where day temperatures seldom exceed 28degC during growing season and where the night temperatures drop to as low as 80degC. Rainfall requirement ranges from 800-1500 mm. Where similar conditions prevail in the highlands of Tanzania, Uganda and Ethiopia these varieties are recommended. Examples in this group include "H 6210", "H 6212", "H 6213", "H 629" and "KH 600-15A"
Medium Altitude Agro-Ecozone: Altitude range is between 1000 and 1800 m. Some of the varieties in this category include "H513", "H 515" and "H 516". These varieties are commonly grown in coffee growing belts maturing in 4-5 months. The favourable rainfall is between 750-1000 mm
Transitional Zone: The altitude in this zone falls between 1000 and 1500 m where the temperature ranges from 12 to 30degC and has rainfall similar to that of high altitudes. "Hybrid 624" is a typical example in this category.
Lowland Agro-Ecozone: Pwani hybrids ("PH 1" and "PH 4") and "Coast Composite" are fairly short varieties resistant to lodging and more tolerant to moisture stress and recommended for altitude range of 0-1250 m. above sea level with 400 mm of rainfall. They have an added advantage of good husk cover hence reduced crop loss though bird, weevil attack and ear rots. They are also suitable under inter-cropping systems.
Dryland Agro-Ecozone: Examples in this category include "Katumani Composite B" and "DLC 1". Katumani "Composite B" is a fast growing open pollinated variety, which is fairly short and produces short cobs. It is a drought escaping variety flowering within 60-65 days and maturing within 90-120 days. The variety performs well within altitudinal range of 1000-500 m above sea level and is a variety for marginal rainfall areas. The variety requires 250-500 mm of rain, and has performed extremely well in arid marginal areas in many parts of Africa particularly in Somalia, Ethiopia, Sudan, Tanzania and Namibia
"DLC 1" also open pollinated is recommended for arid and semi-arid regions. This variety flowers earlier than "Katumani Composite B" by about 4-7 days and is shorter but more prolific. Under unfavourable conditions the variety performs better that "Katumani Composite B". The variety is best suited where rainfall duration is short and amounts to less than 350 mm. The variety is a good substitute where rainfall is erratic and can be recommended for arid marginal areas in the region as "Katumani Composite B".

Some examples of maize varieties in Tanzania
•    "Kilima, "UCA"(OPV): suitable for medium to slightly high altitude (900-1700 m); maturity of 110-130 days; yield potential of 45-65 bags of 90 kg / ha
•    "Staha": suitable for low to medium altitude (1-900 m); maturity of 110-130 days; tolerant to drought and also humid conditions
•    "TMV-1" (OPV) : suitable for low to medium altitude (1-900 m); maturity of 110-120 days"Katumani,
•    "Kito": suitable for low to medium altitude (1-750 m); maturity of 90 days; yield potential of 22-30 bags of 90 kg / ha; drought tolerant
•    "Situka"(OPV): suitable for medium altitude (500-1600 m); maturity of 110-120 days; yield potential of 45-65 bags of 90 kg / ha; tolerant to low nitrogen; resistant to cob rots, grey leaf spot and maize streak virus.

Some examples of maize varieties in Uganda
•    "Longe 4 (OPV)": suitable for low land to mid altitude areas; maturity of 100-115 days; yield potential of 40-55 bags of 90 kg / ha; tolerant to maize streak virus, rust and grey leaf spot.
•    "Longe 5 (Nalongo) (QPM Maize)"; suitable for low land to mid altitude areas;  maturity of 115 days; potential yield of 40-50 bags of 90 kg / ha; quality protein maize with lysine and tryptophan amino acids; drought tolerant; resistant to maize streak virus, grey leaf spot; moderately resistant  to northern leaf blight.
•    "Longe 8 H": suitable for mid-altitude; maturity of 120-125 days; potential yield of 88--10 bags of 90 kg / ha; excellent husk cover; tolerant to cob rots, drought and poor soil; resistant to maize streak virus, northern leaf blight and grey leaf spot; a very popular hybrid in Uganda.

Ecological information

Maize is a versatile crop, growing across a range of agro-ecological zones. With its large number of varieties differing in period to maturity, maize has a wide range of tolerance to temperature conditions. It is essentially a crop of warm regions where moisture is adequate. The crop requires an average daily temperature of at least 20℃ for adequate growth and development. Optimum temperature for good yields is around 30℃. The time of flowering is influenced by photoperiod and temperature. Maize is considered to be a quantitative short-day plant (short days can induce premature flowering). It is grown mainly from 50°N to 40°S and from sea level up to about 3000m altitude at the equator. At higher latitudes, up to 58°N, it can be grown for silage.
Maize is especially sensitive to moisture stress around the time of tasselling and cob formation. It also needs optimum moisture conditions at the time of planting. In the tropics it does best with 600 - 900mm of rain during the growing season. Maize can be grown on many soil types, but performs best on well-drained, well-aerated, deep soils containing adequate organic matter and well supplied with available nutrients. The high yield of maize is a heavy drain on soil nutrients. Maize is often used as a pioneer crop, because of the high physical and chemical demands it makes to the soil. Maize can be grown on soils with a pH from 5 - 8, but 5.5 - 7 is optimal. It belongs to the group of crops that is considered to be sensitive to salinity. Since a young crop leaves much of the ground uncovered, soil erosion and water losses can be severe and attention should be paid to adequate soil and water conservation measures.

Agronomic aspects 

Seed Selection
Kenya seed company contracts specific farmers to grow maize for seed. The maize is then harvested and treated using Thiram-dindane to prevent pest attack and sold to farmers as seed. Farmers are advised to buy fresh seed for planting every season. This is because of the problem of reduced hybrid vigour in the first generation.
Land preparation
Land on which maize is to be grown should be prepared early to allow stubble enough time to rot. Ploughing is done using disc or mould board ploughs. Harrowing is done where the seedbed is rough, although a fine seedbed is not necessary for maize. Maize does well when grown in rotation with other crops such as beans, tobacco, cotton, groundnuts and Irish potatoes. Maize takes a lot of fertility out of the soil. Continuous cropping of maize should be avoided unless the soil is very fertile or where a lot of fertilizers are applied.
Planting Time 
Planting should be done quite early in the rains so that the crop can make maximum use of available moisture. Dry planting should be very crucial as delayed planting always reduces yields. Early planting also reduces attack by stalk borers.
Planting should be done within the first two weeks of the onset of rains. It is recommended that there should be at least 30 cm of wet soil throughout the soil profile before sowing. While the hole is still moist, place two to three seeds in an evenly-spaced line in each hole, with one pip at each side and one in the on the other side. Cover the seeds using the soil heaped next to the hole to leave a level surface. Make sure no stones or heavy soil clods cover the seeds. Leave the mulch cover between the holes intact. Try to complete planting in a day to ensure an even germination and later, an even crop canopy, which will shade out any weed growth.
Spacing and plant population per hectare The recommended spacing and planting density of maize for different areas is as shown in table.

The appropriate planting depth varies from 2 to 10 cm, depending on the weather conditions and the moisture status of the soil. In the highland and medium areas where the soils are well-drained sandy-loam soils, planting depth of 2 to 3 cm is optimal, as deep seed placement retards germination and emergence of maize seedlings. In dry and coastal low land areas where the soil is dry and/or sandy, maize seed should be planted more deeply (5 to 10 cm). This enables the development of a deep root system to obtain the needed water and nutrients. Deep roots penetrate far into the soil and use moisture and nutrients from the deeper depths of the soil.

d). Weed control 

Weeds in maize should be controlled right from the early stages of growth to reduce competition for moisture and nutrients. Two to three weedings should give the crop a chance to grow properly to the point where it can suppress the weeds. Hand weeding is mainly practiced.

Weed control is very important. Maize is very sensitive to weed competition during the first 4-6 weeks after emergence. It should be planted as soon as possible after the preparation of the seedbed. Inter-row cultivation to control weeds and to break up a crusted soil surface may be done until the plants reach a height of about 1 m. In Kenya 2 weedings are necessary for most maize varieties, though a third weeding may be necessary for varieties that need 6 to 8 months. Weeding by hand requires a minimum of 25 man-days/ha.  

e). Water management

Irrigation is used in areas of low rainfall and is particularly valuable at the time of tasseling and fertilisation. Irrigation is necessary for production of green maize.  Plastic film mulching has been adopted in small-scale intensive maize production. It conserves water, warms the soil and keeps off weeds. It is however expensive to install. 

f). Fertilisation

Maize usually responds well to fertilisers, provided other growth factors are adequate. The quantity of manure applied by smallholders is usually very limited. Improved varieties can only reach their high yield potential when supplied with sufficient nutrients. A maize crop of 2 t/ha grains and five t/ha stover removes about 60 kg N, 10 kg P₂O₅ and 70 kg K₂O from the soil. Nitrogen uptake is slow during the first month after planting, but increases to a maximum during ear formation and tasselling. Maize has a high demand for nitrogen, which is often the limiting nutrient. High nitrogen levels should be applied in three doses, the first at planting, the second when the crop is about 50 cm tall, and the third at silking.

Many soils provide substantial amounts of the phosphorus (P₂O₅) and potassium (K₂O) but this is not adequate enough, especially at the seedling stage. Apply P₂O₅ near the seed for early seedling vigour. K₂O is taken up in large quantities but plants' requirement can usually be estimated by soil analysis. K₂O deficiency results in leaves with burnt edges and yellow or light green colour and empty cob ends, while P₂O₅ deficiency results in purple tinged leaves and hollow grains. Nitrogen deficiency shows as yellow or light green stunted plants.Phosphate is not taken up easily by maize and, moreover, some tropical soils are deficient in available phosphate. Zinc deficiency symptoms include shortening of internodes and light streaking of leaves followed by a broad stripe of bleached tissue on each side of the leaf midrib. Occasionally the leaf edges and interior of the stalk at the nodes appear purplish. It is advisable to apply organic manures to improve soil structure and supply nutrients, all before ploughing. 

Nitrogen (N) can be applied in organic farming via green manure (legumes fixing N directly from the atmosphere), farmyard manure (FYM) or compost. Phosphorus can be supplied through FYM, compost, and in the form of rock phosphate (available in East Africa as Mijingu rock phosphate). rock phosphate should be applied in the rows or planting holes at planting to promote root formation., Potassium can be supplied through FYM, compost and ashes. However, fertiliser recommendations based on soil analysis provide the very best chance of getting the right amount of fertiliser without over or under fertilising. Ask for assistance from a local agriculturist office. 

In rain-fed maize growing areas, plant seeds along with the first rain. This will allow roots to absorb the natural nitrates formed with bacterial action in the soil. Roots are susceptible to poor drainage, which causes stunted and yellowing of leaves. Stagnant water results to loss in N through leaching and denitrification (FADINAP, 2000). For more information on organic plant nutrition click here.  

g). Intercropping

In Africa maize does well when intercropped with beans or other legumes. The intercropped legumes should be sown at the time of first weeding in order not to crowd out the young maize plants. Since maize is a heavy feeder and takes considerable nutrients out of the soil, it can only be grown continuously on the richest soils or when heavily fertilised. Recommended legumes for intercropping in Kenya are beans, pigeon peas, cowpeas, groundnuts and soybeans. Other crops that have been tried with varying success include potatoes, cassava and pumpkin. 

Intercropping maize with beans and other legumes regulates pests (leafhopper, leaf beetles, stalk borer, and fall armyworm) and increases the land utility. Intercropping Canavalia (Canavalia spp.) with maize improves soil productivity. Sow Canavalia seeds 4 weeks after sowing maize. Place 1 seed/per hole in a row between maize rows with 50 cm between holes. Allow Canavalia to grow after harvesting maize until it is time to plant the next crop. Then plough the plant materials into the soil (CIAT, 2000). 

Intercropping maize with beans and squash enhances parasitism of caterpillars. This practice increases food sources for beneficial insects whereby increasing abundance of natural enemies. The intercropping system of maize-beans-squash is a low input and high yield strategy in the tropics. Maize yield is increased by as much as 50% over monoculture yield. Although the yields for beans and squash are reduced, the overall yield for the 3 combined crops is greater than when grown separately in monocultures (Agroecology Research Group, 1996). 

Push-pull Desmodium (Desmodium uncinatum) and molasses grass (Melinis minutifolia) when planted in between maize rows keep the stem borer moths away. These plants produce chemicals that repel stem borer moths. In addition desmodium supresses the parasitic witchweed Striga hermonthica. Napier grass (Pennisetum purpureum) and Sudan grass (Sorghum vulgare sudanese) are good trap crops for stem borers. Napier grass has its own defence mechanism against crop borers by producing a gum-like-substance inside its stem, this prevents larva from feeding and causing damage to the plant. Both grasses attract stemborer predators such as ants, earwigs, and spiders. Sudan grass also increases the efficiency of natural enemies, in particular parasitic wasps, when planted as border crops (Herren; Pickett, 2000; ICIPE, 2006). For more information on push-pull click here  

h). Alternative uses of maize in mixed cropping 

• Shading of vegetable crops by planting single rows between vegetables in areas of high intensity of sunshine can increase yields of intercropped vegetables.
• Use as support for runner beans for export or local consumption.

Harvesting and Post Harvest Management

Harvesting

Maize can be harvested by hand or by special maize combine harvesters. The stage of maturity can be recognised by yellowing of the leaves, yellow dry papery husks, and hard grains with a glossy surface. Maize is often left in the field until the moisture content of the grain has fallen to 15-20%, though this can lead to attack by grain borers in the covered cobs. In hand harvesting the cobs should be broken off with as little attached stalk as possible. They may be harvested with the husks still attached. These may be turned back and the cobs tied together and hung up to dry.  

The world average yield in 2014 was 5,616 kg per hectare. Average yield in the USA was 10,732 kg per hectare, while in Africa it was 2,105 kg per hectare. Average yields in Kenya in 2014 was 18 bags/ha (1,660 kg/ha) (FAOSTAT, 2014).  

Post Harvest Handling

The major problems in most maize-producing areas are reducing the moisture content of the grain to below 13%, protection from insects and rodents, and proper storage after harvest. High moisture content with high temperatures can cause considerable damage such as development of aflatoxin producing fungi, making the product unsuitable for human consumption. Maize for home consumption is either sun-dried on the cob for several days by hanging up tied husks, or put in a well-ventilated store or crib. Easy test for moisture content: take a few grains and try to crush them with your teeth - below 13% moisture level the grains are extremely hard and almost impossible to crush this way. Shelling (the removal of grains from the cob) is usually carried out by hand, though several hand and pedal-powered mechanical shellers are now available. The average recovery is about 75%. The shelled grain is dried again for a few days and then stored in bags, tins or baskets. 

The optimum moisture content for storage is 12-13%. In Indonesia seed for the next crop is generally selected from the last harvest. The selected cobs are stored at home in the husk above the fireplace to prevent losses by insects. Crop residues are removed from the field and then used as fodder, fuel, etc.

Markets 

In 2018, Africa produced 75 million tons of maize, making up 7.5% of global production. Maize covers about 24% of African farmland, with an average yield of approximately 2 tons per hectare per year. 
South Africa is the largest producer of maize in Africa, followed by Nigeria. According to USDA reports, maize production in Africa increased by almost 8.2% from 2017 to 2022, estimated to be 90.8 million metric tons. In 2021, South Africa contributed 1.34% of the global maize production, according to a survey done by USDA Foreign Agricultural Service. Africa imports 28% of its maize from non-African countries because much of its maize production relies on rain, making it vulnerable to shortages and famines during droughts.
(iita.org, Apraku & Fakorede, 2006, PROSEA, 2016, FAOSTAT, 2021)
 

Nutritional value and recipes

Corn seeds comprise three layers. The outermost is the pericarp, abundant in fiber. The middle layer, the endosperm, is mainly composed of carbohydrates and the inner layer, the embryo, contains protein, vitamins, and minerals. When eaten in its unprocessed state, like fresh corn on the cob or whole-grain cornmeal, maize offers dietary fiber that aids in digestion and contributes to blood sugar stability.
Maize contains notable amounts of Vitamin B3 (niacin), which plays a role in metabolism and skin health, as well as folate (Vitamin B9), essential for cell division and particularly important during pregnancy. Maize also contributes to notable amount of phosphorus, essential for bone and teeth health, as well as magnesium, important for muscle and nerve function. It contains potassium, which helps maintain fluid balance, supports nerve signals, and aids in muscle contractions. Zinc is present in smaller amounts and contributes to immune function and wound healing. Yellow maize has a high amount of vitamin A (carotenoids), while blue, purple, and red variety is rich in antioxidants and phenolic compounds.
Furthermore, the nutritional content of maize can vary depending on its variety and how it's prepared. Whole maize, especially when minimally processed, is generally considered more nutritious than highly refined corn-based products like corn syrup or cornstarch. Sweet corn, is a low-starch variety with higher sugar content. Despite the sugar in sweet corn, it is not a high-glycemic food, ranking low or medium on the glycemic index.

Note
Maize is relatively low in protein and lacks some essential amino acids. Therefore, it is often consumed in combination with other foods, such as beans, to create a more balanced amino acid profile.
Webmd, (n.d), Healthline (n.d), Wikifarmer (n.d)

Table 1: Proximate nutritional value per 100g of edible portion

Source (Nutrient data): FAO/Government of Kenya. 2018. Kenya Food Composition Tables. Nairobi, 254 pp. http://www.fao.org/3/I9120EN/i9120en.pdf

^$ Draining the water several times leaches away water soluble nutrients significantly.

^a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO

^b NHS (refers to saturated fat)

^c https://www.hsph.harvard.edu/nutritionsource/water/

^d British Heart Foundation

^e FDA

^f NIH

^g Mayo Clinic

Recipes
Maize can be prepared into a host of products. It can be eaten roasted, boiled, popped etc. In Africa, the most common use is by grinding the maize into flour and making a kind of stiff porridge that varies in consistency from one community to another. Another common use is mixing the maize with legumes and sometimes with leafy vegetables or tubers.
1. Muthokoi
(Kamba, Kitui, Kenya)
Ingredients
    ½ Kg dry maize
    1 Kg Beans
    Water
    Salt to taste
    1 onion
    2 tomatoes
    3 tablespoons ghee 
    Vegetables (optional)
     Pestle (muthi)
    Mortar (kinu or ndii)

Method
    Put the dry maize in a mortar and add some little water (if too dry)
    Pound the dry maize with a pestle till the testa comes off
    Put the pounded maize in a uteo (tray) or calabash and winnow to remove testa (wewa)
    Remove the bigger maize particles first called muthokoi by shaking the uteo and leave the smaller particles called muthungululo which is milled to flour for making ugali
    Boil the muthokoi shortly for 30 minutes then add beans (cowpea, pigeon pea, common beans-Phaseolus vulgaris). Green beans can also be used.
    Cook the mixture of muthokoi and beans well till well cooked
    Season to taste and serve. 
    Can add ghee to the boiled mixture or fry the mixture with onions and tomatoes 

Provides 7 servings
(Source: Maundu et al., 2006)

2. Makanda
(Kamba, Kitui, Kenya)
Ingredients
    ½ Kg Green maize
    Vegetables (pumpkin leaves, cowpea, kikoe, amaranth)
    1 Kg Beans 
    Ghee 

Method
    Take green maize grains and winnow to remove dirt
    Mix the maize with dry beans and clean well 
    Put in a pot with water and boil till well cooked
    Add salt to taste
    Add ghee and stir
    Frying is optional
    Can also be fried with a vegetable
(Source: Maundu et al., 2006)

3. Ndutu (Maize with beans)
(Uru, Kilimanjaro, Tanzania)
Ingredients:
4kg. maize
2kg. beans (small beans/ mrondo)
4tbs.soda (mmbala/ magadi)
Enough water
Procedure:
    Boil maize with water and soda (3tbs) until soft in a clay pot
    Wash to remove husks 
    Mix boiled maize with beans, soda (1tbs) and water. 
    Boil until soft, serve

Variation: 
    Mash the mixture
    Add salt to the taste
    Add either cooking oil, butter, animal fat or ghee
    Add onions, carrots, sweet pepper
    Reduce amount of soda 

Serve:
    As a main dish 
    As a packed lunch when travelling or going to farm
(Source: Yvonne Guga†)

4. Loshoro (Maize grain porridge)
(Arumeru, Arusha, Tanzania)
Ingredients: 
     4 kgs maize grain (makande)
     30 green banana (ndizi ng’ombe)
     2- 4 ripe banana
     2 lts fresh milk
     Hot water

Procedure
     Boil grain maize with water in clay pot until soft 
    Peel the bananas, cut into cubes and add into the pot to continue boiling
    Peel ripe banana, cut into cubes and add into the mixture to boil until soft while covering the pot
    Remove the pot, mash the mixture well, add hot water and stir to make more soft
    Add fresh milk while stirring to make liquid like porridge. Serve.

Variation 
    Use sour milk instead of fresh milk
    Add beans (Nganamna or pigeon pea)

Serve 
    Can be eaten for 3 days 
    Special for celebration e.g. wedding 
    As a main dish and refreshment
(Source: Yvonne Guga†)

5. Kitalolo (maize porridge with vegetable)
(Uru, Kilimanjaro, Tanzania)
Ingredients
    4 kg dried maize
    2 kg beans
    20 green banana
    2 tbs soda
    2 handful African nightshade
    2 lts sour milk 
Procedure
    Boil maize with water and soda until soft
    Add beans and boil it until done
    Peel bananas, cut into cubes, add into the pot to boil 
    Sort, cut into small pieces the night shade and add into the mixture to boil until soft
    Remove the pot, mash the food, add 1 lts of water while stirring then cool 
    Add sour milk to make liquid like porridge. Serve.
Variation
    Wash the maize to remove the husks and clean
    Use fresh milk instead of sour milk
    Add batter or animal fat
Serve 
    Only women are allowed to eat Kitalolo and children, not for men.
(Source: Yvonne Guga†)

6. Makukuru/Ngararimo (Mashed maize with Beans)
(Marangu, Kilimanjaro, Tanzania)
Ingredients
    4 kg maize
    2 kg beans (nganana/ pigeon pea)
    2tbs soda
    Water
Procedure
    Boil the maize with soda and water in a clay pot until soft
    Add beans into the pot to boil until done
    Remove the pot, mash to make semi hard. Serve

Variation
    Add salt to the taste
    Add cooking oil or fat to add palatability 
Serve 
    Serve without mashing
    Serve with stew or sour milk 
    Serve as main dish
    Serve as a packing lunch
(Source: Yvonne Guga†)

7. N’gande (Kande) (polished maize and beans)
(Bena, Njombe, Tanzania)
Ingredients
2 cups of polished maize
1 cup of beans
1 teaspoon salt
2 to 3 litres of water or more

Procedure 
Wash maize and beans
Put maize and of water in a sufuria
Boil for 1 hour 
Pour beans in the maize 
Add water, salt and continue boiling for another 1 hour 
 Serve 
(Source: Makiindi Kunulilo)

8. Congolese fufu

Ingredients
•    Maize flour
•    Manioc flour

Method
•    Put water in cooking pot and put on fire
•    Add maize flour immediately  before water gets hot
•    Let cook as you stir with a cooking stick for about 15 minutes till colour changes to light brown
•    Add manioc flour and stir on fire till it hardens
•    Remove from fire

Serve with vegetable e.g. manioc leaves
(Source: Maundu et al., 2006)

9. Styfpap (Stiff porridge, Vuswa, Vhuswa)
South Africa
This stiff-like porridge is what the vegetables are traditionally served with.

Ingredients
4 cups water
2 cups maize meal
1 teaspoonful salt

Preparation
Boil the water over a high heat and add salt
Lower the fire to medium heat and add the maize meal while stirring
When the maize meal has obtained the desired degree of stiffness, simmer and cook for 15 minutes
To obtain stiffer porridge, more flour is added till desired consistency is achieved.
Served with traditional vegetables
Yields 3 to 4 servings
(Source: Maundu et al., 2006)

10. Umqa (umxoxozi and maize mix porridge)
(Xhosa, South Africa)
Ingredients
1 kg Umxoxozi (tsamma, Xhosa melon Citrullus lanatus) fruit
500 ml water
2 mugs of coarse maize flour
Salt and sugar to taste

Preparation
Cut Umxoxozi (Xhosa melon) into cubes and remove the seed
Boil the water and add the melon and cook till soft 
Add the maize flour and stir
Add the salt and sugar to taste
Simmer for 15-20 minutes, stirring 2 – 3 times
Give a final stir, 
Serve
Yields 5 servings
This is a favourite meal
(Source: Maundu et al., 2006)

11. Madumbe fruit and leaves recipe  
(South African recipe)
Ingredients
2 kg coarsely ground maize flour
20 Madumbe (Taro) leaves
2 mugs coarsely ground maize flour
2.5 litre water
2 pumpkins (small butternut size)

Mix the ground maize flour with the Take the bottom biggest and smallest leaves to cook morogo
Preparation
Harvest approximately 20 leaves, clean and remove the stems
Cut the leaves
Cut the leaves 
Add about 2.5 litres water to a pot and boil the leaves while covered
When the leaves are soft, add cut pumpkin (2 small butternut size) into pot
Stir 
Cook till pumpkin is soft 
Add about 2 kg ground maize meal to the pot
Cook covered till the water covers the maize meal
Add one tablespoonfuls of salt, mix
Cook for 5-10 minutes
Serve 
Yields 5 servings
(Source: Maundu et al., 2006)

12. Sweet potato leaves-maize porridge
(South Africa)

Ingredients
6 mugs sweet potato leaves
5 litres water
5 mugs coarsely ground maize flour

Preparation
Cut the cleaned leaves into small pieces. 
Add to the pot
Add the water and boil till soft
Add the maize flour to the pot, cook for 3 minutes
Add the salt
Stir and cook closed for 30 minutes
Stir and cook closed for 15 minutes
Stir and cook closed for 5 minutes 
Remove from the fire
Serve alone
(Source: Maundu et al., 2006)