Growing Wheat ~ In all African countries, wheat consumption has been steadily increasing during the past 20 years as a result of growing population, changing food preferences and a strong urbanization trend which has led to a growing ‘food gap’ in all regions, largely met by imports. In 2013 alone, African countries spent over $12 billion dollars to import more than 40 million metric tons of wheat, equating to about a third of the continent’s food imports.
Growing Wheat in Ghana – Types of Wheat:
Wheats are classified based on species, commercial types, and growth habit. Based on these, there are sixteen species, two commercial types: bread (Triticum aestivum) and macaroni or Duran wheat (Triticum durun); and three growth habits (winter habit wheat, spring wheat and facultative wheat). Winter wheat lies dormant during a winter freeze
Growing Wheat in Ghana – Major cultivated species of wheat:
- Common wheat or Bread wheat ( aestivum): A hexaploid species that is the most widely cultivated in the world.
- Durum ( durum): The only tetraploid form of wheat widely used today, and the second most widely cultivated wheat.
- Einkorn ( monococcum): A diploid species with wild and cultivated variants. Domesticated at the same time as emmer wheat, but never reached the same importance.
- Emmer ( dicoccum): A tetraploid species, cultivated in ancient times but no longer in widespread use.
- Spelt ( spelta): Another hexaploid species cultivated in limited quantities.
Harvested wheat grain that enters trade is classified according to grain properties for the purposes of the commodities market. Wheat buyers use the classifications to help determine which wheat to purchase as each class has special uses. Wheat producers determine which classes of wheat are the most profitable to cultivate with this system.
Growing Wheat in Ghana – Ecology and Climatic Requirements:
The production of wheat in Ghana is within latitude 10-140 N and altitude of 240 – 360 m above sea level in the Sudan and Sahel savannah. Optimum air temperature for growth and the development of grain is 18 – 25 0C.
High temperatures during developmental stages hasten growth and development, while shortening various developmental stages, making it impossible to achieve full yield potentials of the crop.
Production of wheat was initially confined to the Chad Basin and since temperate varieties were used, its cultivation was confined to the dry cold period between November and March, thus necessitating the use of irrigation
Temperature requirement for wheat plays significant role in site selection for wheat cultivation, in addition to temperature requirement, wheat thrives best in well drained fertile loam sand to medium texture clay loam and area of low night temperature.
Growing Wheat in Ghana – Sowing Date:
Sowing date significantly influence crop growth, development and yield. Although research to develop rain-fed wheat variety is on, wheat is basically a temperate crop, requiring temperate conditions which only exist in the Sudan and Sahel savannah during the dry cold season of November/ December. Thus the crop is usually sown between November/December to be harvested March/April.
The optimum time for seed sowing is mid-November. Sowing earlier or later than Mid November will affect yield in wheat crop. Delay in seed sowing has been observed to expose the crop to high temperatures, aphid and stem borer attacks.
Growing Wheat in Ghana – Seed Treatment:
Establishing an adequate crop stand is a prerequisite for a successful wheat crop, thus seed treatment is a vital process in achieving this.
Seed treatment will ensure high percentage germination, good crop stand; and all things being equal, good crop yield. Seed treatment with appropriate pesticide will enhance better seed germination by preventing or reducing the incidence of pests. Apron Star 50DS applied at the rate of 10g of Apron Star for 4 – 6 kg of seeds is the common practice.
Growing Wheat in Ghana – Land Preparation:
Land preparation requirement for wheat depends on the cropping history of the land to be used. As a dry season crop, land preparation usually begins early November after the harvest of the last rain-fed crops.
It is however, not uncommon to have land preparation done before the end of October. The current crop under cultivation prior to incorporating the wheat crop into the cropping system, will determine when to begin the process of land preparation.
The Site should be ploughed and harrowed to a good tilt. Since wheat crops are grown under irrigation in Ghana, there is usually no need for ridging as irrigation is by gravity. Water movement by gravitational pull requires achieving a level of slope. Levelling the field to a slope of 0.25 – 0.30% to a drain located at the tail of the field will ensure free water movement. Sunken beds are prepared in such a way to allow for free water movement.
Growing Wheat in Ghana – Seed Sowing: Broadcasting, Drilling and Dibbling:
Seed sowing is an important operation requiring, utmost care. Establishment of adequate crop stand is a prerequisite for a successful crop and this depends on seedling emergence, which may be affected by sowing method employed by farmers.
Sowing method employed by farmers is basically determined by the available technology rather than by the expected yield. Basically wheat crop can be drilled, dibbled or broadcast. However, broadcasting has been observed to reduce plant establishment as seeds are said to be lost to pests and unfavorable weather conditions. Consequently, high seed rates have been recommended when seeds are broadcast in order to compensate for seed loss.
The main reason given for drilling wheat was better germination, which resulted in higher stands compared to broadcasting. Though better crop establishment and crop yield has been reported when wheat is drilled compared to other sowing methods, however, wheat drilling is an expensive technology in the form of labour requirements for drilling or machinery employed in seed drilling. Thus, seed broadcasting or dibbling is prevalent on farmers’ plots.
Broadcasting, it was observed, even when followed by harrowing or raking does not bring seed in perfect contact with the soil for adequate water uptake. Sowing methods employed by farmers vary considerably from area to area, the vast majority of the farmers broadcast their seeds.
Growing Wheat in Ghana – Spacing
Spacing is only relevant when wheat crop is drilled or dibbled, but not in broadcast wheat plots, which involves even spreading of seeds. When drilled, spacing of 25 – 30 cm is usually observed between rows. In dibbled stands, seeds are dibbled at 25 – 30 x 25 – 30 cm apart.
Growing Wheat in Ghana – Seed Rate:
Seed rate of 120-140 kgha-1 is recommended when sowing wheat. Higher seed rate is encouraged when broadcasting as against drilling or dibbling. When seeds are broadcast, it is important to rake in the seeds to reduce exposure to ant predation.
Growing Wheat in Ghana – Fertilizer Application:
Wheat responds well to NPK fertilizer application. Application of 100 – 120 kgNha-1 and 40 – 60 Kg P2O5 ha-1 and 40 – 60 kg K2O ha-1 has been recommended. P and K should be applied prior to seed sowing and incorporated into the soil.
Except in sandy soils, N can be applied prior to seed sowing as single dose. However, for highly porous sandy soils N should be applied in split doses, first at planting, then three or four weeks after seed sowing.
Current recommendations often indicate that the second application of nitrogen be done when the ear (not visible at this stage) is about 1 cm in size (Z31 on Zadoks scale). Several systems exist to identify crop stages, with the Feekes and Zadoks scales being the most widely used.
Each scale is a standard system which describes successive stages reached by the crop during the agricultural season. Crop management decisions require the knowledge of stage of development of
In particular, spring fertilizer applications, herbicides, fungicides, growth regulators are typically applied at specific stages of plant development.
Growing Wheat in Ghana – Weed Control and Pest Control:
Cereals, including wheat crop, are generally most susceptible to competition from weeds in the first few weeks of growth. Competition can be minimized by sowing into clean seedbed; at or immediately after
soil preparation. The advantage of row sowing cannot be over stressed, for they allow weeding to be carried out. Broadcasting wheat seeds during seed sowing hamper such operation.
If herbicide is to be employed in weed control, knowledge of the predominant weed on the farm is necessary. The time of wheat cultivation does not coincide with period of optimum weed interference. However, as temperature warm up in February, weeds will begin to emerge.
For this reason, manual hoe weeding, or post emergence application of chlorotoluron at 2.0kg aiha-1 or application of bentazone at 1.5kg aiha-1 at four weeks after sowing is recommended. Serious pest
incidences have not been reported in wheat crops in Ghana.
However, delay in sowing can lead to aphid and stem borer infestations. There are also
incidences of rodent and bird attacks.
Growing Wheat in Ghana – Wheat Farming in Ghana – Wheat Pests and Diseases
It is a seed borne disease; infection occurs during Loose Smut flowering through wind-borne spores. The infection remains dormant inside the otherwise healthy looking seed but the plants grown from such seeds bear infected inflorescence. Infection is favored by cool, humid conditions during flowering period of the host plant.
Control: Disease can be easily controlled through seed treatment with systemic fungicides.
Stripe Rust /Yellow Rust: – Spreads through air-borne urediospores
Control: – cultivation of resistant varieties is the main strategy of control.
The disease requires high temperature and high humidity. This disease is more severe in late sown crop and causes substantial yield losses through formation of shriveled grains. Most of the varieties are susceptible or moderately susceptible. The disease can be controlled through one spray of propiconazole.
Powdery mildew can easily be diagnosed by the white, powdery patches that form on the upper surface of leaves and stem. With age, the patches turn dull dirty white and may have small black specks embedded.
This disease can spread to all aboveground parts of the plant, including ear head and awns. The disease infects plants during periods of high humidity (not necessarily rain) and cool to moderate temperatures. Low light intensity, which accompanies dry weather and a dense crop canopy favour this disease.
Control: Avoid excessively dense, stands by using adequate seed. For chemical control, one spray of propiconazole on disease appearance.
This disease is favoured by cool, moist weather with high humidity. Spores are produced on crop debris and reach the leaves through rain splash or wind. Apart from ear head infection, it can cause seedling blight and foot rot leading to lodging. In severe cases, it can cause shriveling of grains and low-test weights.
Seed Gall Nematode/ Ear cockle
The nematodes are spread through seed galls in the seed lots during planting and harvesting. Wet weather favors larval movement and infestation. The nematode invades the crown and basal stem area, finally penetrating floral primordia. This leads to formation of nematode galls in ear heads.
Control: Use of clean seed.
They can cause considerable damage, especially when feeding in large numbers but under normal conditions, losses are not much. Chemical pesticides are recommended for this pest in wheat.
Brown Wheat Mite
The Brown wheat cause damage through mite infestation sucking mouth parts. When present in large numbers, mites cause a silvery flecking on leaves.
This is an insect that attacks various legumes as a pod border. It is seen damaging wheat ear heads at grain development stage when major hosts are not available.
Growing Wheat in Ghana – Water Management:
Wheat will grow in areas with rainfall as low as 15 inches (38.1 cm). However, wheat fields in these arid areas will not a have a crop for a full year before the wheat. Commercial wheat farming in Ghana is entirely dependence on irrigation. Effort to grow rain fed wheat is still rudimentary.
Wheat crop grown on sandy soils should be irrigated frequently than those cultivated on clayish soils. For sandy loam, irrigation intervals of 5-7 days until booting state is recommended and subsequent irrigation should be at 7 days intervals. In medium to heavy soils 7 – 8 days irrigation interval is recommended.
Water stress at flowering will negatively affect yield by reducing grain number and weight. Irrigation should be terminated two weeks to crop. In situations where wind is a threat, causing breakages, or where variety grown is prone to lodge, there may be the need to terminate irrigation early. In either case, fall panicles tend to rot on contact with water.
Growing Wheat in Ghana – Harvesting and Processing
When wheat is ready for harvest, the heads of the grain start to bend the stalks with the weight of the kernels. This, in combination with the golden colour, indicates that it is time to harvest the wheat (10 – 12 % moisture level). Wheat which is sown in mid-November is usually ready for harvest in April.
Wheat normally requires between 110 and 130 days between planting and harvest, depending upon climate, seed type, and soil conditions. After harvest, the field is cleared and prepared for planting again. Farmers using good rotation practices do not plant wheat in sequential years, although they may return to the field later.
Although wheat can be combined harvested, in Nigeria, wheat harvest is basically accomplished with the use of sickle. Where sickles are used, the harvest is tie into shelves for threshing on hard platform. The crop is then winnowed to separate the chaff from the grain.
The grain can be processed and used or stored until required. Once the kernels have been separated, they can be ground into flour. There are many classifications for wheat flour, depending on what part of the seed is used and the hardness of the endosperm. Wheat kernels have three parts: the small germ, the large endosperm, and the rough outer casing known as the bran.
Hard wheat is suitable for making pasta and bread, and soft wheat is used for other wheat products that
do not require high gluten content. If flour is made solely from the endosperm, it is known as white flour. If the germ is ground as well, the product is called germ flour. Flour that uses the whole kernel is called whole wheat. When making flour that doesn’t use the whole kernel, the bran and germ are processed and sold separately.
Growing Wheat in Ghana – Processing: Traditional method:
Harvesting →Threshing →Winnowing → De-stoning (sorting to remove stones and foreign materials → Cleaning in water to remove adhering soils → Draining →De-hulling in mortar →Winnowing to remove bran → Washing de-hull grains →Sun-drying →Milling.
Wheat Farming in Ghana – Wheat Processing
After harvesting the wheat is milled to obtain wheat flour. The milling process grinds the wheat into tiny particles which is then sifted out as flour. The yellowish flour is bleached to give the attractive white colour of the commercial flour.
The ﬂour provides nutritious food and the waste (wheat bran) is used as chicken or dairy feed. Wheat ﬂour is used industrially in distilleries, bakeries and straw plating.
Wheat Farming in Ghana – Marketing
The producers may sell the wheat to the National Cereals and Produce Board, a Government parastatal or directly to the millers e.g. Unga Limited. All the wheat produced is consumed locally.