Introduction
Importance of soybean in the global economy
Soybean is among the major industrial and food crops grown in every
continent. The crop can be successfully grown in many states in Nigeria
using low agricultural input. Soybean cultivation in Nigeria has expanded
as a result of its nutritive and economic importance and diverse domestic
usage. It is also a prime source of vegetable oil in the international
market.
Soybean has an average protein content of 40% and is more
protein-rich than any of the common vegetable or animal food sources
found in Nigeria. Soybean seeds also contain about 20% oil on a dry
matter basis, and this is 85% unsaturated and cholesterol-free.
The rapid growth in the poultry sector in the past five years has also
increased demand for soybean meal in Nigeria. It is believed that
soybean production will increase as more farmers become aware of
the potential of the crop, not only for cash/food but also for soil fertility
improvement and
Striga
control. The market for soybean in Nigeria is
growing very fast with opportunities for improving the income of farmers.
Currently, SALMA Oil Mills in Kano, Grand Cereals in Jos, ECWA Feeds
in Jos, AFCOT Oil Seed Processors, Ngurore, Adamawa State, and PS
Mandrides in Kano all process soybean.
IITA along with partners has developed improved technologies for
soybean production. This handbook outlines crop production practices
that farmers may use to grow soybean profitably in Nigeria.
Why grow soybean?
It is good for food—soy-milk, soy-cheese,
•
dadawa
, Tom Brown
(infant weaning food),
It is the source of an excellent vegetable oil,
•
It is used in industry,
•
It improves soil fertility and controls the parasitic weed,
•
Striga
hermonthica,
Soybean cake is an excellent livestock feed, especially for poultry,
•
The haulms provide good feed for sheep and goats.
•
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Conditions necessary for soybean production
Soybean growth is influenced by climate and soil characteristics.
Soybean performs well in the southern and northern Guinea savannas
of Nigeria where rainfall is more than 700 mm.
However, short-duration varieties can thrive in the much drier Sudan
savanna when sown early and with an even distribution of rainfall
throughout the growing period. The time for planting soybean depends
upon temperature and day length. Soybean is a short-day plant and
flowers in response to shortening days. It can be grown on a wide range
of soils with pH ranging from 4.5 to 8.5. Soybean should not be planted
in sandy, gravelly, or shallow soils to avoid drought stress. It should not
be grown in waterlogged soils or soils with surfaces that can crust, as
this will lead to poor seedling emergence.
Preparing to plant
Land preparation
Clear all vegetation before land preparation. The seedbed may be
prepared manually with a hoe or animal-drawn implement or tractor
(Fig. 1). Well-prepared land ensures good germination and reduces
weed infestation. You can plant on ridges or on a flat seedbed.
Figure 1. Preparing land for soybean production using a tractor.
3
Variety
Ecology
Characteristics
Striga
control
TGX 1448-2E
Southern and northern
Guinea savannas
Medium maturing, high yield,
low shattering, high oil
content
,
excellent grain color
Good
TGX 1835-10E
TGX 1485-1D
Guinea savanna
Guinea savanna
Early maturing, rust resistant,
pustule resistant
Early maturing, pustule
resistant, rust susceptible
Not known
Not known
Table 1. Recommended soybean varieties for Guinea savanna
ecological zones in Nigeria.
N.B.
Early and extra-early maturing varieties are strongly recommended in the Sudan savanna
because of the low amount and duration of rainfall in the zone.
Choice of variety
Selected soybean varieties grown in Nigeria are presented in Table 1.
Choose a variety suited to your agroecological zone. Soybean variety
selection should be based on maturity, yield potential, lodging, drought
tolerance, and resistance to pests and diseases. The maturity period
should be the first consideration when choosing a variety suited to your
geographical zone. Consider varieties that are earlier maturing rather
than late maturing in areas with low rainfall. Although later maturity
increases the yield potential, it is risky to grow late-maturing varieties in
drier environments because of late-season drought.
Seed cleaning and preparation
Use high quality seeds of the selected variety (Fig. 2). Soybean seeds
easily lose their viability. It is common for soybean, even when stored
properly, not to germinate after 12 –15 months in storage. Therefore,
use seeds that are not more than 12 months old to ensure good
germination. Sort out the good seeds for planting to ensure that they
are free from insects, disease infestation, and weed seeds. Do not
purchase seeds from the open market as the germination potential
is not guaranteed. Planting poor quality seeds will not produce a
good yield (Fig. 3). Always buy seeds from seed companies or seed
producers nearest to you.
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Soybean germination test
Test seeds for germination before planting. The germination rate
should be 85% or more to obtain a good stand. To conduct a quick
seed germination test, select 400 seeds randomly and sow 100 seeds
each in four wooden or plastic boxes or a prepared seedbed. Sow one
seed/hole at a distance of 10 cm between the seeds. Soak cloth- or
paper-lined germination boxes or the seedbed well with water before
sowing and provide water every morning and evening. Start counting
the seedlings 5 days after sowing and complete the counting within
10 days. A total count of 320 germinated seeds or more indicates a
germination rate of 80% and above. When the percentage germination
is 80% or less, the seed rate has to be increased accordingly to achieve
100% germination.
Planting
Date of planting
Soybean produces well over a wide range of planting dates, if moisture
is available. The recommended dates for planting soybean in different
ecological zones in Nigeria are presented in Table 2. Do not plant too early
Figure 2. Use good
seeds for planting.
Figure 3. Do not use poorly
sorted seeds.
5
because a prolonged dry spell after planting may result in permanent wilting
of the crop and the need for replanting. Late planting, on the other hand,
may expose the crop to attack by some late season pests and also deprive
the crop of sufficient moisture if the rains stop early. Plant soybean as soon
as the rains are well established.
Seed rate
About 50–70 kg (20–28 standard
mudus
) are required to obtain a
population of 444,444 plants/ha for soybean varieties. Since soybean
seed size varies among varieties, it is essential to consider planting in
terms of seeds/unit area. It is not uncommon to see sizes ranging from
12.6 to 18.9 g/100 seeds
Seed dressing
Treat seeds with fungicides, such as Captan, Apron Plus, or Thiram, at the
rate of 1 sachet/8 kg of seeds before planting for protection against soil-
borne fungal diseases.
Plant spacing and sowing
Sow soybean by hand, planter, or by drilling. Plant 3 to 4 seeds/hole at a
spacing of 75 cm between rows and 10 cm between stands. Alternatively,
drill seeds at 50–75 cm between rows and 5 cm within rows. For the early
maturing varieties, a spacing of 50 cm between rows and 5–10 cm within
rows is recommended because they respond better to narrow spacing
than the late-maturing varieties.
Do not sow seeds more than 2–5 cm
deep. Deeper planting may result in loss of vigor or failure of seedlings to
emerge.
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