Maize Value Chain

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Maize (Zea mays) Production


Maize (Zea Mays) is a cereal crop that grows across a range of agro-ecological zones in Nigeria, though it is grown slightly more in the Northern part of the country. Two types of maize are grown in Nigeria, the yellow and white variety and due to its rate of adaptability, Maize is not a seasonal product and some of the major producing states in Nigeria includes Adamawa, Bauchi, Borno, Yobe, Jigawa, Gombe, Taraba, Plateau, Sokoto, Kebbi, Katsina, Nasarawa, Niger and Zamfara.

Nigeria, the most populous country in Africa (about 165 million) is essentially agrarian in nature with over 80 per cent of her food needs being produced by peasant farmers cultivating, in many cases, less than 2 hectares of land. Maize is the most important cereal crop in sub-Saharan Africa (SSA) and an important staple food for more than 1.2 billion people in SSA and Latin America. All parts of the crop can be used for food and non-food products. In industrialized countries, maize is largely used as livestock feed and as a raw material for industrial products.

It is on record that more than 60% of Nigeria’s production of maize is consumed by the industrial sector for production of flour, beer, malt drink, corn flakes, starch, syrup, dextrose and animal feeds. There is high demand for corn {maize} starch in Nigeria. With a population of over 165 million people and an estimated national population growth rate of 5.7% per annum, an average economic growth rate of 3.5% per annum in the past five {5} years, Nigeria has a large market for corn {maize} starch.

Industries in need of cassava starch include textile, pharmaceuticals, food and beverages, paper and packaging, manufacturing and chemicals. The national demand for corn {maize} starch in Nigeria is estimated at about 800,000 tons annum while the current national supply is estimated at 350,000 tons per annum.

Land clearing and Soil preparation

These farmers practice zero tillage, a necessary requisite of no till farming in which crops are grown without cultivating the soil. In conventional farming the land is prepared by ploughing and harrowing using animal- or tractor-drawn implements, but in this farming community the practice has drastically waned and is getting close to becoming extinct in favour of no-till farming. Here are how they practice land clearing in preparation for the planting of glyphosate-resistant corn in sloping cogonal lands:

Weed Slashing

The area to be planted with corn is first slashed either partially or entirely. Tools which are deemed essential to this land clearing operation are the bolo with thin blade curved towards the tip (we call this bolo lagaraw) and an arm’s-length segment of a tree stem with a short stub of a branch at the tip and with thickness just enough to be grasped by one hand (a sort of single-pronged wooden rake which we call kaw-it). Slashing always starts from below and proceeds upward.


Immediately after slashing or just before planting of corn, the firebreaks are cleared of cut weeds and other combustible materials. This can be done with the use of the common rake but the farmers rather use indigenous materials such as the kaw-it and bamboo culms with one or two short stubs of branches at the tip (like an improvised fork).

Likewise, cut weeds are moved away from the bases of coconut or other standing crops to prevent injury to the plants during burning.


This is done during dry, sunny days. Burning, despite various raised concerns, is a convenient, fast, and inexpensive practice that marginal farmers are used to in land clearing. It is usually commenced starting from low elevation at a time of the day when there is wind. As the burning progresses, the farmer is always alert to contain the fire to prevent damage to standing crops and to prevent the fire creeping outside of the intended area to be burned.

Spraying herbicide

A day after burning, the area may be planted to corn. However, if the same area had thick growth of cogon and has not been cultivated before, the farmer applies herbicide to further reduce root mass and ensuing growth of weeds. A week or two are commonly allowed to pass until the grass weeds have regrown and then herbicide is sprayed.

Adopting the above into an approximately one-hectare portion of our farm, land preparation was completed in two weeks. The activities included blanket slashing, raking, burning, and herbicide spraying. Labour requirement was as follows: slashing- 8 man-days (MD), raking- 2MD, burning- 1MD, and herbicide spray- 1MD for a total of 12MD.


Climatic and Soil Requirement


Maize crop can be cultivated on a very wide range of agro-climatic conditions. However, moderate temperature with plentiful supply of water are most favourable. Higher temperature throughout the crop season curtail the total crop duration and lead to poor crop yield.

Temperature below 12 o C and higher than 30 o C does not favour its cultivation. Wide variation in day and night temperature helps in higher production. Realization of such temperature range in Indian conditions in the traditional kharif season is not possible. However, this type of climatic condition can be realized during rabi season. Under Indian condition kharif crop of maize is sown at a temperature in the range of 35-40 oC, which is very high.


Maize is grown on a wide variety of soils ranging from fairly coarse sand to the heaviest of clays. It grows best on fertile, friable, well drained warm loam and silty loam soils, well supplied with organic matter and available nutrients. Maize can be grown under a wide range of soil reactions, but the optimum pH range is from 5 to 7.

The soils in Southern transition zone are red sandy, red loamy, and laterite gravelly type. Eastern dry zone soils belong to red loamy, red sandy and red lateritic type. In Central dry zone red sandy to red loams are the major types.

In all the above soils, low organic matter content and coarse texture of the soil is hindering crop’s productivity. Thus, addition of organic manure helps in improving fertility status of soil besides improving the soil physical conditions.

The low organic carbon status of these soils limits the crop production, as organic matter not only supplies nitrogen but also helps in improving physical properties of soil. Hence, in these soils, liberal application of FYM in addition to nitrogenous fertilizers is essential for boosting the productivity.

The ill-effects of crust formation in these soils can be prevented or reduced by keeping the surface moist, use of pre-soaked seeds, ridge planting, surface mulching, organic residue application and use of soil conditioners ……… etc.



There are different varieties of maize in the world today and the type you choose to produce will depend on consumer preferences and market demand in your area. In some localities, white corn is more popular than the yellow variety. In some other areas, it is vice-versa. However, the best maize varieties grow fast, are high yielding, mature earlier than the local varieties and are resistant to major pests and diseases. There are now some hybrid varieties that use much less water and can often survive in drought-prone areas. There are also late-maturing and early-maturing varieties of maize. Late-maturing varieties mature in 110-120 days and are good for zones with a long rainy season. Early-maturing varieties mature in 90-100 days and can be planted after a late-maturing variety in zones with two seasons of rainfall. There are also extra-early varieties which mature in 80-90 days. These can be planted in zones with very short rainy season (usually 2-3 months long).

Recommended maize varieties for different Agro-ecological zones.

Agro-ecological zone Recommended maize variety
Sahel Open pollinated



8644-27, 8341-5


8322-13, 8425-8

Sudan Open pollinated Hybrid DMRSR-Y

8341-6, 8341-5


8322-13, 8425-8, 8644-27

Northern Guinea savanna Open pollinated Hybrid DMRSR-Y

8341-6, 8341-5


8322-13, 8425-8, 8644-27

Southern Guinea savanna Early season Open pollinated TZSR-Y, TZSR-W, TZB, TZPB, FARZ34, FARZ227,




Planting moisture requirement

Dryland maize should be planted on a full soil moisture profile. Irrigated crops should be irrigated pre-plant and then if using flood irrigation not watered until 6 weeks old (pre-tasselling). If conditions are hot and dry, a quick flush 2 – 3 weeks after emergence may be required. Maize is not tolerant of waterlogging especially during seedling and flowering stages.

Seed details

Seed has both size and shape gradings. Size varies from 4400 seed/kg (small) to 2500 seed/kg (large). Seed shape consists of rounds or flats. Flat seed is generally best in plate seeders, while round seed is preferred by air seeders. There is no difference between the crops produced by these seed shapes.

Information on the germination percentage and the date the test was conducted should also be with the bag.


Cultural practices/Planting method:

Seed at 25kg/ha of grain to achieve 54,000 plants/ha (75cmx25cm) for one plant per stand or 90x40cm for 2 plants per stand. In the southern guinea savannah and forest zones where the rainy season is long enough for two crop, plant in March/April for the first early crop and in August for the second or late crop. Unlike the Northern Guinea Savanna, sudan and sahel zones where only one crop is possible, plant as soon as the rain are established. Planting depth depends on the moisture level of the soil where depth for 2-3 cm is adequate for moist soil and 5-10 cm is recommended for dry planting. Deep seed placement under dry planting is recommended so that seed germinate only after adequate rains have fallen. However, the depth of planting should be uniform to allow uniform plant growth.

Management Practices

Nutrient deficiency symptoms:

  • Nitrogen deficiency- leaves turns yellow
  • Phosphorus deficiency- leaves turn purplish during early growth.
  • Potassium deficiency- leaves turns yellow or yellowish green streaks on leaves.
  • Magnesium deficiency- a general loss of green colour which starts at the bottom leaves and later moves up to the stalk.
  • Zinc deficiency- Pale yellow leaf base, light yellow streak of the leaves between the veins, stunting and delayed maturity.


Fertilizer recommendation for maize base on soil test

Nutrient Fertility class Nutrient rate per ha Fertilizer rate per ha
Nitrogen Low 120kg N Apply half the rate of Nitrogen at planting or 2-3 weeks and the remaining half at 5-6 weeks after planting
Medium 60kg N Apply 6 bags of 20-10-10
High 30kg N Apply 3 bags of 20-10-10
Phosphorus Low 60 kg P2O5 Apply 7 bags of single super phosphate at 2-3 WAP
Medium 30 kg P2O5 Apply 3 bags of single super phosphate at 2-3 WAP
High Nil Nil
Potassium Low 60 kg K2O 2 bags of Muriate of Potash at planting or 2-3 WAP
Medium 30 kg K2O 1 bag of Muriate of Potash at planting or 2-3 WAP
High Nil Nil


Weed control

Begin thinning out when three to four leaves appear, around 15 days after germination. Remove surplus and weaker plants in order to obtain consistent density (one to two plants per seed hole, after thinning). Regular thinning is required to produce a good yield. It can be done manually or chemically, using a selective herbicide.

Remove any weeds, especially during the vegetative phase of cultivation. Two to three hoeing sessions will be required: the first during thinning; the second when applying the urea; and the third just before the harvest, if the plot has a lot of weeds. If using herbicides, apply a pre-emergence herbicide such as Primextra + atrazine just after sowing and before the emergence of the maize seedling.


Water management

The irrigation water management depends on season as about 80 % of maize is cultivated during monsoon season particularly under rain fed conditions. However, in areas with assured irrigation facilities are available, depending upon the rains and moisture holding capacity of the soil, irrigation should be applied as and when required by the crop and first irrigation should be applied very carefully wherein water should not overflow on the ridges/beds. In general, the irrigation should be applied in furrows up to 2/3rd height of the ridges/beds. Young seedlings, knee high stage (V8), flowering (VT) and grain filling (GF) are the most sensitive stages for water stress and hence irrigation should ensure at these stages. In raised bed planting system and limited irrigation water availability conditions, the irrigation water can also be applied in alternate furrow to save more irrigation water. In rain fed areas, tied-ridges are helpful in conserving the rainwater for its availability in the root zone for longer period. For winter maize, it is advisable to keep soil wet (frequent & mild irrigation) during 15 December to 15 February to protect the crop from frost injury.


Leaf Blight

Manifestation of oval to round, yellowish-purple spots on leaves. The affected leaves dry up and appear as if burnt. In severe cases, the plants may become stunted, resulting in poorly-formed ears.
The crop can be sprayed with Dithane M-45 or Indofil @ 35-40 gms or Blue Copper @55 -60 gms in 18 litres water, 2 -3 sprays at 15 days interval, will effectively control the disease.
Insect Pests:
Stem borer

These borers feed on leaves in the earlier stages. Later on they bore into the stem and cobs, rendering the plant unproductive.

  • After harvest, the stalks and stubbles should be collected from the field and burnt.
  • Crop can be sprayed twice with Thiodan 35 EC @ 27 ml in 18 litres water, once 20-25 days after germination and the second spray at the time of grain formation (in endemic areas).

Red Hairy Caterpillars

Caterpillars feed and destroy the whole plant if the attack is in the early stages of growth.


  • Egg masses and young caterpillars should be collected as soon as detected, and destroyed.
  • The field should be ploughed out after the crop is harvested, so as to expose pupae.
  • Thiodan 35 EC @ 27 ml in 18 litres water should be sprayed only as last resort.


Tiny, soft bodied insects, usually green in colour. Nymphs and adults suck the sap from leaves and young shoots.

The crop can be sprayed with Rogor 30 EC @ 18 ml in 18 litres water.

Grass hoppers

Short-winged hoppers, laying eggs in the soil at a depth of 7.5 to 20 cms, adults feed on foliage.
Thiodan 35 EC @ 25 ml or Ekalux 25 EC@ 28 mi in 18 litres water can be sprayed.

These pests attack young seedlings as well as mature plants; attack is also visible on roots and lower parts of the plants.

Thiodan 4 % Dust @ 12-15 kg per hectare is applied and mixed well with the soil.


Time to harvest Maize can store for a considerable period in unprocessed form without undergoing deterioration. Its shelf life greatly depends on the prevailing ambient temperature and relative humidity, and other factors like the inherent moisture pests and diseases. Therefore, recommended postharvest handling and managing operations involve the manipulation of the above factors in order to obtain high quality maize grains.

Quality control starts with harvesting. Harvesting is the single deliberate action to separate the cob from its grown medium. The optimum time of harvesting maize is when the stalks have dried and moisture of grain as about 20-17%. Requirements during the Harvesting Process

  • 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 postharvest 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 postharvest losses. Transfer them to the drying place (like the crib) immediately.
  • Dry on concrete or canvas not on bare soil Activities before Harvesting Currently, most of the maize grown in Uganda is harvested by hand.

Considering the need for a farmer to keep the cobs clean, to dry the cob immediately and avoid infestation of the harvested cobs, a farmer makes the following preparations:

  • 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. Harvesting Harvest the maize cobs and transport them to the crip without putting them on soil to avoid contamination.

Postharvest Handling

After harvesting, farmers should clean all the materials used in the process of harvesting and store them properly, away from sources of contamination and insect breeding places. The same materials may be needed during the proceeding operations e.g. to transport cobs from the crib for threshing or to transport grains to the store. If the materials are not cleaned properly, they can easily contaminate clean grains or become source of pest infestation since at times pest infestation starts from the field.


After harvesting, the greatest enemy of grain is moisture. Wet grains and attract insects and mould. Therefore, the grain must be dried as soon as possible after harvesting. Drying is the systematic reduction of crop moisture down to safe levels for storage, usually 12%-15.5% moisture content. It is one of the key postharvest operations since all down-stream operations depend on it. This is particularly so in some regions of Uganda where humidity and rainfall remain high at harvesting delaying the harvest and constraining actual drying. Sometimes the next season starts early when the crops are still in the field as much as possible the choice of varieties should be such that they mature at the beginning of dry season.

Drying permits the escape of moisture from grain moisture to an acceptable level, which can sustain very low metabolism. The enzyme activities and grain tissue respiration is reduced to a very low level, thus inhibiting sprouting/germination. During drying, the dry air rapidly takes moisture away from the grain, especially if the air is moving and has got low humidity. Grain can be dried in a crib before shelling and on tarpaulins after it has been shelled.

Avoid drying the maize on the ground. Grain that is in contact with the ground will absorb moisture and pick up dirt and insects. Drying maize on plastic sheets or mats is becoming a common practice with farmers who are trying to keep maize off the ground during drying. This practice is discouraged because of the following reasons:

  • Someone would have to watch the grain while it dries.
  • At night or when it rains, the grain must be brought under shelter.
  • Grain can be washed away in case of a sudden down pour.
  • Risk of contamination from dusts, soil, stones, animal droppings, fungal and insect infestation.
  • Losses from birds, poultry and domestic animals, resulting into contamination and quantitative losses.
  • The method is time consuming and labour intensive involving lots of grain handling.


Shelling is commonly done by beating maize cobs with stick in a sack or a confined floor space where farmers can afford it. It is better to use a maize shelter as beating maize will result in physical damage which makes it more vulnerable to pests and moulds and damage to the germ. Using a maize shelter is preferred although it will not be afforded by most farmers. Storage The principal objective in any maize grain storage system is to maintain the stored grains in good condition so as to avoid deterioration both in quantity and quality. During storage, the grain must remain dry and clean. Grain storage can be extended for up to 2 years without any significant reduction in quantity and quality. However, the majority of farmers sells off their maize grains cheaply soon after harvesting due to anticipated losses in storage and later buy food at exorbitant prices. There are improved storage structures that can prolong the storage duration until market prices for grains are favourable. Improved storage structures A good storage structure should:

  • Provide protection from common storage loss agents such as insect pests, rodents, moulds, birds and man.
  • Maintain an even, cool and dry storage environment. The maize should be placed on pellets above the floor to avoid cold conditions that may lead to moulds.
  • Should not allow re-wetting of grain by either moisture migration or rain. • Offer reasonable protection from thieves.
  • Be simple and inexpensive to construct using, where possible, locally available materials and skills. Be easy to clean and repair.
  • Grain should be protected from rodents’ Perfect storage hygiene is the basic prerequisite for successful storage. All hygiene measures are very simple, particularly effective and cheap. They can thus be perfectly performed by any farmer with little effort.

Store room

Bag storage of shelled grains in well-designed store rooms is the most suitable in a tropical country like Uganda. Although bulk system of storage also exists and has its advantages, bag storage is more appropriate for Ugandan farmers because of the following reasons:

  • At the moment all buyers in Uganda require bagging before dispatch.
  • The transport system available is more suited to transporting bagged than bulk grains.
  • Bagged grain is easily quantified when receiving, dispatching or checking stock.
  • Bag storage requires less capital investment than bulk storage.
  • Bag storage is easy to manage, cheap and efficient.
  • The bag system involves little risk in particular as far as long term storage is concerned.


Siting and orientation

  • The store should be located on a raised site with good drainage to ensure that there is no stagnant water in its store.
  • Set up the store with the longitudinal side on an East-West axis (less radiation on the building) or exposed to the main wind direction. This creates balanced temperature conditions thereby reducing the danger of condensation.
  • Locate the store on firm soil with good road connections to enable easy transportation.


Losses due to poor storage


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:

  • Inadequate drying
  • Physical damage due to poor shelling/threshing methods
  • Poor storage methods (exposure to moist condition)
  • Insect infestations.

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.


Careless handling of either maize cobs or grains can lead to spillage. This leads to loss in terms of quantity. Spillage can also lead to loss of quality in case contaminated grains or cobs are again mixed with the clean stuff. In this case, contamination will lead to mould development. The situation will be worse if the spill gets into contact with moisture. Losses due to spillage are common during shelling that is done by beating the cobs with sticks. 1


There are three major markets for maize and its allied products in Nigeria.

Corn as Human Consumption:

Unlike in developed countries where a major portion of maize produced is used for animal feed or biofuel, maize is a significant part of diets in Africa in general and Nigeria in particular. Experts expect that the demand for maize as human nourishment will increase in tandem with Nigeria’s population growth. There will therefore also be a higher demand for corn (maize). This market currently accounts for about 50 per cent of the Nigerian corn demand.

Corn as Animal Feed

Corn is a favourite raw material for animal feeds, mainly because it is cheaper than many of the other feed alternatives and yet provides the required nutritional content for livestock. As a result, about 35 percent of corn produced in Nigeria is used in animal feed production.


Maize for Industrial Consumption

It is estimated that about 15 per cent of Nigeria’s current maize produce goes for industrial use, due to its high starch content. The starch obtained from maize is processed into several additives, agents and ingredients such as sorbic acid, sorbitol, dextrine, and lactic acid.

These are used in the manufacture of common household items such as cosmetics, ink, medicines and wall paint.

If you’ve eaten popcorn before, you know you’ve eaten the product of maize. Other by-products from maize are shoe polish, batteries, syrups, ice cream, and glue. Companies such as Nestle and Cadbury also buy corn to produce cereal-based breakfast brands like corn flakes, while companies such as Nigerian Breweries and Guinness purchase maize to use as a major raw material for the production of beer.

In industrialized countries, the starch from maize is also used to produce bioethanol, a form of renewable fuel. Nigeria is aiming to achieve this level of sophistication as well.

Types of Marketing Cost

This chapter concentrates on the costs of marketing maize3. The types of costs described are broadly similar to the costs associated with the marketing of other crops and the cost-calculation methodology outlined can also be used for other crops.

In moving produce from farmers to the eventual buyer, in most cases a mill, traders have a large number of costs, some of which may not be immediately obvious to farmers. It is important that farmers understand these costs. Without such an understanding they are likely to look at the large difference between the price the traders offer them and the price that mills pay the traders and conclude that the traders are exploiting them. Extension workers need to understand marketing costs in order to be able to explain to farmers the reasons for differences between traders’ buying and selling prices and in order to be able to calculate whether the price a trader is offering is reasonable. Various types of marketing costs are:

  • packaging;
  • transport;
  • handling;
  • weight losses;
  • storage;
  • capital/other costs;

The first cost faced is for packaging. If the farmer provides the bags, then he will be justified in expecting a higher price. The most important cost is usually for transport and this will be understood by farmers, although they may not always understand that transport costs can be more than for a simple journey from one place to another. A less obvious set of costs are those incurred in handling the bags of maize. Bags may be loaded and unloaded several times before reaching the final buyer, all of which needs to be paid for. Between the farmer and the mill there is likely to be some loss of weight compared with the quantity purchased. The grain may be too damp at the time of purchase and may lose weight through drying out. Maize may be lost through holes in the bags or through theft. If the trader keeps the maize in store for several months, then it may be attacked by insects or rodents. Storage incurs other costs too, including the cost of renting the warehouse and disinfestation charges. A cost which will not be obvious to the farmer is the cost of money or capital costs. Even when the trader does not deliberately store maize, the time between paying the farmer and being paid by a mill could be several weeks. In countries where interest rates are high, the cost of money can therefore be significant. There are also lots of other small costs to pay and the marketing cost calculation must, of course, include profit for the trader. Without such profit he will not trade and there will be no one to buy the farmer’s maize.



While some large farmers in, for example, Zimbabwe deliver maize in bulk to the mill, this is not a realistic option for traders buying from small farmers. Bags are required. There are many possible arrangements over bags. Some traders expect the farmer to provide the bag, while others will give the farmer a bag in exchange. Others will pay a higher price for bagged maize. Larger traders may supply bags in advance to farmers, although here they run the risk that farmers may sell their maize to other traders.

Whether packaging is a significant cost to the trader will ultimately depend on whether the mill he sells maize to eventually returns the empty bags to him free of charge, or whether he has to purchase bags each time he visits a producing area. In the calculations made later in Figures 4 and 5 it is assumed he is able to recycle bags and thus the cost to him of packaging is small as grain bags can be used many times. However, this will not always be the case.



Maize is transported on the shoulder or head, by bicycle, wheelbarrow, ox-cart, car, pick-up, bus or truck. As most farms are not situated right next to a road, either the farmer or the trader will have to transport the maize to the nearest road without using motorized transport. When the trader does this his costs will be increased and the price to the farmer will be lower.

Small-scale traders may buy too few bags at one go to justify hiring pick-ups or trucks. They will either transport bags of maize by bus or on a passing vehicle. It should be remembered that their costs will include not only the cost of transporting the bags but also the amount they have to pay for their transport to and from the producing area. Smaller traders who move produce in this way often have to take several rides in order to get to their destination. This can both be expensive and time-consuming.

During the maize buying season, there is a lot of produce moving out of producing areas but the volume of produce being transported into these areas is relatively small. Thus trucks travelling to maize growing areas to collect maize will often travel empty. The cost to the trader who hires a truck will invariably be the cost of a two-way journey rather than a one-way trip. This needs to be built into cost calculations. Further, a trader who charters a truck will almost always have to pay a fixed fee for the journey, which takes no account of the quantity he loads onto the truck. If he can fill the truck with maize bags the cost per bag will therefore be significantly lower than if he has spare capacity. Figure 3 on page 46 illustrates this graphically.

Traders delivering to mills often have to wait in line at the mill for some time. Many of the mills in the region were set up without much warehousing capacity, it being assumed that they would receive regular deliveries from marketing board warehouses. With liberalization, mills have often been slow to take over available warehouses and have frequently been processing maize as and when it arrives, both for lack of storage and because of a lack of finance. With limited storage capacity at the mills, traders have had to wait for other maize to be milled before they can unload their trucks. In Zambia, it reportedly took up to five days to unload maize at a mill in the peak season. This adds to costs, both the transport costs and the cost of the trader’s time.

Figure 1
Transport costs per ton according to capacity utilization

Fig 1

Note: A fixed charge for the truck is assumed for the first 100 km, with a charge per kilometre thereafter



Maize can be handled on many occasions between the farmer and the buyer. The trader can either do this himself or pay someone to do it. Examples of the occasions when maize is handled for a fee when a collector/trader sells maize in a market are:

  • packing grain into bags after purchase from the farmer;
  • carrying the bags to the roadside;
  • loading the bags onto a truck;
  • off-loading the maize at the market;
  • moving the maize from the vehicle to the selling point;
  • cleaning the maize;
  • moving unsold maize to a store at the end of the day;
  • moving it back to the selling area the following day.

A trader selling to a mill may handle the bags in the following ways:

  • packing grain into bags after purchase from the farmer;
  • carrying the bags to the roadside;
  • loading the bags onto a pick-up;
  • off-loading the maize at his store;
  • reloading the maize onto a larger truck;
  • unloading the maize at the mill.


Weight losses

The weight the trader sells is unlikely to be exactly the same as the weight he buys. If the time between buying and selling is only a few days the loss may only be small, say one percent or so. But if the trader stores the maize for some time and carries out activities to improve the quality of the maize, then the difference in weights can be considerable, even as high as ten percent. In the days when all maize was handled by marketing boards and maize was sometimes stored for up to two years, losses on stored maize often reached 30 percent.

Reasons for losses in weight are discussed below. It should be realized that not all of these losses are food losses. For example, a trader may “clean” the maize. Clearly there is no food loss here but the weight the trader sells is not the same as the weight he buys. When post-harvest food losses are calculated the fact that losses in weight are not all losses in food is sometimes overlooked, thereby creating an impression that the post-harvest and marketing systems are inefficient when, in fact, they may be quite efficient.


Spillage can be caused by a variety of factors. Using of old bags with small holes in them or failing to close the bags properly leads to maize falling from the bags. Rough handling, for example by throwing bags from trucks, can make the problem worse. Poor roads lead to greater bag movement on the truck, resulting in greater spillage.


Traders who transport bags on the top of buses cannot guard their bags against theft all the time because they are sitting in the body of the bus. Traders who do not accompany their maize bags on trucks run the risk that small quantities will be pilfered, either by the truck driver or by passengers he picks up. While a handful of maize may be an insignificant amount, many handfuls soon mount up. The potential for such loss by the trader has to be built into the calculations of the price he can afford to pay farmers.

Moisture loss

Maize purchased soon after harvest will probably have a high moisture content and will continue to lose moisture for some time. Depending on the time between purchase and sale this can lead to a fairly noticeable weight loss. Where it is too moist traders may even take steps to dry it. While moisture loss is not a loss of food, it nevertheless represents a cost to the trader and must be built into marketing cost calculations.


Maize bagged by small farmers often contains straw, stones and other “foreign matter”. Traders selling in local markets cannot sell such maize and have to clean it before sale. This therefore represents another weight loss. Some farmers often try to defraud traders by deliberately placing large stones or other objects in a bag of maize. In the final analysis it is the other farmers who suffer from such practices as such fraud will affect the price the trader is willing to pay in the future. The extension officer needs to stress this point to all farmers.

Traders may clean maize before delivery to mills but this is not normal practice. Mills often deduct a certain amount from the gross weight of maize delivered by traders, in expectation that it will contain foreign matter. Traders also sometimes try to compensate for foreign matter by paying farmers for less than the full weight.

Damage in storage

Maize held in storage is vulnerable to attack from insects, rodents and birds, particularly if it is not well fumigated or if it is stored outdoors under tarpaulin. This can lead to significant weight loss when the maize is stored for a long period, for example when the trader is storing in the hope that the price will rise at the end of the marketing year.

The best way of treating weight loss in marketing cost calculations is to ask the question …

How much does the trader need to buy in order to sell 100 kg … (or one bag — or one ton)?

This is the method that is adopted in Figures 4 and 5 on pages 52 and 53 which show two calculations. It is a better method than the more common one which involves simply adding the cost of the lost maize at the end of the calculation. This is so because the latter method takes no account of the fact that weight which is purchased, but not sold, nevertheless often has to be transported and stored.

Maize damage by insect

Maize damaged by insects in storage can suffer serious weight losses

Maize damaged by insect


Smaller traders may have to store unsold maize in a market overnight. Larger traders may store maize while they put together a truckload for delivery to a distant mill or because they have no immediate buyer for it, for example if the mills are not buying or have insufficient storage. The most common reason for storage in mature private-sector marketing systems is to take advantage of price rises later in the season. This practice is not yet widespread in the region, but it can be expected to grow as traders become more sophisticated.

All storage has a cost. There are four basic types of cost:

  • the charge made by the warehouse owner for storing the bags of maize or, where the store is owned by the trader, the depreciation in the value of the store (or tarpaulin) and the cost of operation (electricity, etc.) and maintenance;
  • costs associated with the maintenance of quality while the maize is in store, for example, the cost of chemicals;
  • losses in quantity while the maize is stored. There is also the risk with long-term storage that the maize will also suffer a loss of quality, so reducing its value;
  • capital costs.


A note on inflation

To simplify presentation, the calculations shown in this Guide take no account of inflation. Unfortunately, many countries continue to experience rapid price increases and extension workers must bear this in mind when advising farmers on which crops to grow, on whether to store and on how and when to market. Many farmers have problems in understanding the concept of inflation and in realising that although the price they get for their maize may be going up they are not necessarily better off. To help understand the impact of inflation we use the idea of the “real” price.

Let us first begin with this simple example

The maize price in May is: $ 100
The maize price in November is: 150
The price increase is: 50
Farmer’s storage cost for six months is: 20
Farmer’s profit from storage is: $ 30

Here it looks like storage is a good idea. However, if we now calculate the “real” price then the picture changes dramatically. In some countries of the region inflation has at times been well over 100 percent a year. Let’s, for this example, assume it is around 60 percent a year and that in the period May–November prices went up by 30 percent. Then:

The maize price in May is: $ 100
The maize price in November is: 150
The “real”* maize price in November is: 115


The “real” price is calculated by dividing the actual price by the percentage prices have gone up plus 100. The result is then multiplied by 100. Hence, with 30 percent inflation, the real price is ($150 ÷ 130%) × 100 or $115.

The “real” price increase is: 15
Farmer’s storage cost for six months is: 20
Farmer’s loss from storage is: $ 5

Thus, inflation can turn an apparently profitable activity into a loss-making one.

Considering a different situation, let us assume that the farmer has two choices in selling his maize. He can sell to a trader who will pay him $100 in cash now or he can sell to a trader who will pay him $110 in two months’ time. However, if inflation is rising by 5 percent per month, the “real” price in two months’ time is $100. So there is no reason for the farmer to sell to the second trader.

Since it is somewhat difficult for farmers to understand the idea of inflation, extension workers can help them understand by relating prices to the cost of buying things. For example, if the farmer sells his maize for $100 in May, how many bags of fertilizer will he be able to buy with that money? How many will he be able to buy in November? Inflation means that he will be able to buy less in November than in May.

This is because the farmer could put the $100 in the bank and earn interest or he could spend the $100 buying household supplies or farm inputs, before prices go up. However, if all he plans to do with the $100 is keep it in his house and do nothing with it then he might be better off accepting the $110 of the second trader.


 Capital costs

Capital costs may not be very visible but they are extremely important. To operate, a trader may have to borrow money from a bank, from relatives or from a moneylender. The interest he pays on that money is a cost. If a trader uses his own money it cannot be said that he has no costs because he could have left the money in the bank to earn interest, instead of using it for trading. The cost of using his own funds is thus the interest he is not receiving. Economists call this an opportunity cost.

Several countries in the region have very high interest rates, which can fluctuate rapidly. It is thus in the trader’s interest to sell the maize he buys from farmers as quickly as possible, unless, of course, he thinks he can make more money by storing it for a long period. Unfortunately, it is not always easy for the trader to get his money back quickly. Mills may not pay on delivery. They may require a period of credit, which can be as much as a month, and then may not always pay at the end of the agreed period. Sometimes, as already noted, mills may stop buying for a time, leaving the trader with no choice but to store the maize.

Buying from farmers can also take time. A trader may spend several days going from farmer to farmer in order to put together a truckload. If he pays cash, he is paying interest on that cash all the time he is in the rural areas buying.

Other costs

There are lots of small costs which the trader may face. Individually they may be small but all added together they can be quite significant. It is often necessary to weigh the maize and a payment has to be made to the weighbridge or person in the market offering a weighing service; traders selling in markets will usually have to pay market fees; some local councils, provinces, etc. may levy taxes on maize marketed or transported in their area; police and other officials may levy “unofficial” taxes at road blocks or in markets; larger traders have overhead costs, such as office accommodation and phone and fax charges.



Corn Exports by Country

Sweet Corn Cravings

Sweet corn cravings

Global sales from corn exports by country amounted to US$28.8 billion in 2016.

Overall, the value of corn exports was down by an average -19.3% for all exporting countries since 2012 when corn shipments were valued at $35.7 billion.

Year over year, the value of global corn exports appreciated by 1.6% from 2015 to 2016.
Among continents, North American countries accounted for the highest dollar worth of corn exports during 2016 with shipments valued at $11.1 billion or 38.7% of the global total. In second place were Latin America (excluding Mexico) and the Caribbean at 29.1% while 28.6% of worldwide shipments originated from European shippers. Asia at 1.8% and Africa at 1.7% are smaller exporters.

The 4-digit Harmonized Tariff System code prefix for corn (also called maize) is 1005.


Corn Exporting Companies

Below are corn-processing conglomerates that represent large players in the global corn market. Shown within parenthesis is the country where the company is headquartered.

Archer-Daniels-Midland Co. (United States)

Bunge Limited (United States)

Cargill, Inc (United States)

Ingredion Incorporated (United States)

Louis Dreyfus Holding B.V. (Netherlands)

Mriya Agro Holding (Ukraine)

SLC Agrícola (Brazil)

Syngenta AG (Switzerland)

Tate & Lyle Public Limited Company (United Kingdom)

Vanguarda Agro (Brazil)



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