AgroNotes Series 7: Soybean Production

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Enterprise Brief:

Soybean, soy bean, or soya bean (Glycine max) is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu and tofu skin are made. Fermented soy foods include i am willow, fermented bean paste. Fat-free (defatted) soybean meal is a significant and cheap source of protein for animal feeds and many packaged meals. For example, soybean products, such as textured vegetable protein (TVP), are ingredients in many meat and dairy substitutes.

Soy beans contain significant amounts of phytic acid, dietary minerals and B vitamins. Soy vegetable oil, used in food and industrial applications, is another product of processing the soybean crop. Soybean is the most important protein source for feed farm animals (that in turn yields animal protein for human consumption

Variety selection

Soybeans has a number of varieties, so when selecting a particular variety, farmers need to consider characteristics such as growth habit, shattering resistance, pod height and resistance to pests and diseases.

Common Varieties

Variety Maturity period (days) Yield (Kg/acre) Attributes
Namsoy 4M 100 800-1200 Has large seeds with black hilum, resistant to soybean rust; tolerant to pod shattering. May shatter if harvesting is delayed. Protein content is 43% and oil content 20 %
Maksoy 1N 90 800-1200 Small seeded variety with brownish helium, resistant to rust; very resistant to shattering.  Protein is 41% and oil content 17 %
Maksoy 2N 105 800-1200 Excellent seed appearance, Large seeds with white helium, resistant to soybean rust, tolerates pod shattering. Protein content 38%, Oil content 20%
Maksoy 3N 100 1000-1400 Medium large seeds, yellow helium, resistant to pod shattering, resistant to lodging and tolerant to soybean rust. Protein content 36% and Oil content 22%

Growth environment

Soybean requires ample rain during its growing period from germination up to pod filling and development stages. There should be adequate sunshine at physiological maturity and drying period.

Land Preparation

A fine seed bed and fertile loam soils are required to ensure good crop growth and development. Soils should be deep and well drained


Planting should be done early and when there is sufficient moisture in the soil to ensure good germination. Plant seeds with high germination rate of over 85 %. In fields where inoculated soybean has never been grown, seed should be inoculated with Rhizobium japonicum. To inoculate 20 – 25 Kg of soybeans, mix with one sacket (200g) of rhizobia before planting. Plant treated seeds immediately so that the bacteria does not die.

Spacing is 60 x 5cm for 1 seed/ hole or 60 x 10 cm for 2 seeds/ per hole. Recommended plant population is 120,000 plants per acre and depending on the seed size, seed rate is 25- 30 Kg/ acre. Gap filling may be done 7 days after emergence.

Soybeans intercropped with other crops such as maize, cassava, sweet potatoes, cotton or bananas, among others. The spacing is 90 X 30cm for 1 maize seed per hole or 90 X 60cm for 2 maize seeds per hole then 1 line of soybeans in between. Farmers can have 1, 2, 3 or more rows of soybeans between maize rows but adjust spacing accordingly.


Keep the fields free of weeds at all times. Weeding is done in 3rd and 6th weeks after planting. Third weeding is only done where necessary.

Soil fertility management

Soybean being a legume and if properly inoculated, can use the nitrogen in the atmosphere (N2) for plant growth by entering into symbiotic associations with Rhizobium japonicum. This also enriches the soil with nitrogen for subsequent crops. Soil fertility can be improved by:

  • Improvement of nutrient-retaining ability of soil by adding organic manures to the soil.
  • Improvement of soil drainage
  • Control of soil erosion
  • Crop rotation by growing crops which have different growth habits, nutrient requirements.
  • Minimum tillage practices
  • Timely weed control.
  • Resting / fallow periods where feasible

Pests, diseases and control

Although soybean diseases have increased in Uganda, the available varieties are resistant to most of them.

1. Soybean rust; this is the most destructive disease so far and requires immediate attention. Resistant varieties such as Namsoy 4M and Maksoy 1N are the cheapest control against this disease

However fungicides such as Dithane M45, Saprol and Felicur can be used to control soybean rust if susceptible varieties have been planted.

2. Soybean Mosaic Virus and Bacterial pustule; to control use clean disease free seeds, resistant varieties and crop rotation.

Pests and control:

Stink bugs – Use recommended insecticide e.g. thionex or rogor to spray when the situation warrants after careful scouting to assess the level of injury. For leaf eaters and rollers, spray with insecticide or use also resistant varieties.

Rats – To control use traps and when necessary rodenticides.

Birds – They are a menace at emergence of the crop (during 1st 2 weeks after onset of germination). The birds include guinea fowls, doves, chicken and other domestic birds. Scaring is the best solution


The crop is ready for harvesting when pods dry and give rattling sound when shaken. If harvesting is delayed for so long, the pods may start shattering. Prolonged delay to harvesting can also lead to poor seed germination later, after planting.

The mature plants may be uprooted or cut at ground level and loosely shaken for later threshing. Never heap harvested soybeans when they are damp; it reduces seed quality. Harvest in dry conditions.


Harvested plants should be kept dry. They may be spread on a platform and sun dried. Hand threshing is suitable for small quantities. Threshing should be done as soon as possible.


Dry the seeds thoroughly to about 10% moisture content it should not be possible to dent the beans with your teeth store grains in sacks/ bags.

It is preferred you store seeds for planting in polythene bags to prevent moisture absorption. Until planting time, keep the seed in a cool dry part of the house on raised benches. At every planting time, use seed harvested in the preceeding season to avoid poor germination.

From the Team

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