How to grow soya bean


SOYA BEAN is a strategic crop for Zimbabwe’s economy.
It is now supported under the Government’s Command Agriculture Programme for Import Substitution.
Although many farmers have received some of the soya bean inputs, training on how to grow soya bean is still required.
That will ensure maximum production to meet contracted yield volumes.
The University of Zimbabwe is working with the department of Agricultural and Technical Extension Services (AGRITEX) and stakeholders in the soya bean value chain to assist farmers with technical support and training.
This article is part of that effort.
It briefly outlines the main issues on how to grow soya bean.
Farmers are also encouraged to attend any training sessions organised by AGRITEX in their areas.
Radio and television programmes are also on cards to provide more technical and advisory support to farmers.
Regular readers of The Patriot may also recall the series of articles on soya bean published earlier.
While efforts are underway to provide farmer training, I thought it prudent to publish a summary of the main issues relating to growing soya bean for the benefit of readers who can share it with other farmers.
For ease of reference, the material is presented in point form.
Importance of soya bean and how to grow it
1. Soya bean is very easy to grow; any farmer with seeds and a piece of land can grow the crop.
2. Where certified seed is not available, farmers can use their own retained seed, the same way as we do groundnuts. Use 100kg seed per ha.
3. When buying retained seed from other people, always check germination percentage even before paying. A 75 percent or higher germination is preferred. One can make up for low germination percentage by increasing the seeding rate.
4. How does a farmer save money by growing soyabean?
l Less basal fertiliser compound L or D, 3–5 bags (50 kg)/ha is used.
l Mix seed with one sachet rhizobium inoculant per ha; it costs US$5 only;
l If no rhizobium use AN or urea as top dressing at 3–4 bags (50kg) per ha.
l Split the top dressing e.g. 50 percent at flowering and another 50 percent at the pod-filling stage.
l Good yields can be obtained with cattle manure, organic fertiliser, compost or anthill soil. Plant soya on the most fertile field; you will always harvest.
l Seed from previous crop can be planted, saving money.
l Soya bean is not attacked by weevils, there is no need to buy grain protectant chemicals.
5. What are the benefits of growing soya bean?
l Soya bean adds organic matter to soil as leaves drop at maturity.
l It improves soil fertility to give higher yields for crops grown in rotation;
l Soya grain is highly nutritious;
l Contains proteins, carbohydrates, minerals and immune-boosting chemicals.
Enhances health, including that of HIV and AIDS infected;
l Has a good market price;
l Easily processed at home for food;
High market prices provide good cash income.
6. What of soil type and rainfall are suitable for soya bean?
l Generally soils and rainfall good for maize will do for soya bean: 600 mm and above.
l Well drained soil types ranging from loamy sands to red and black soils;
l Yields are higher on heavy than light soils;
Soya will grow well on soils previously amended with animal manure, anthill soil
l Fields previously receiving heavy doses of basal fertiliser on previous cereal crop will give some yields even if little or no fertiliser is applied.
l If soil pH is less than five, plough in lime (300– 500 kg/ha) or cattle manure;
l Soya is suited to: Natural regions one, two and three.
l Mashonaland West, Central and East, parts of Manicaland, Midlands and Masvingo are suitable.
Pockets of good soils in Matabeleland North and South will also produce soya especially under irrigation.
l Moisture is critical at flowering and pod-fill stages;
l Apply supplementary irrigation if mid-season drought occurs.
l In high altitude areas e.g. Eastern highlands, plant early to give crop long growing period.
l Soya requires long periods of sunshine to reach full maturity.
l Crop stops growth when temperatures fall from March onwards.
7. Inputs for soya bean production
Seed: 100 kg/ha;
l Rhizobium inoculant, one sachet/ha;
Compound fertiliser or Soya blend 250 – 350 kg/ha;
l Herbicides pre-emergent: grasses: Alachlor +/- 2L/ha; broad leaf: Metribuzin: 0.7-1L/ha; post-emergent: Classic @35g/ha & Agil @1L/ha; Fusilade Super 1L/ha. Check for other herbicides with reputable suppliers.
Read labels, follow instructions for safety.
8. Land preparation
l Plough or disc to get a fine tilth;
l Use spike harrow to break large clods if necessary.
l Remove green weeds by weeding or ‘burn’ with herbicides (Glyphosate/paraquat).
Rip sloping lands for better capture of rainwater.
9. Inoculating seed with Rhizobium Inoculant
l Inoculant bacteria fix N for soya crop; no need for AN/urea top dressing.
l One sachet is enough for 100kg seed to plant one hectare.
l In sandy soils two sachets can be used.
l Dissolve 7.5 tea spoonfuls sugar in 750 ml clean water.
l Add one sachet of inoculant; mix thoroughly.
l Place 100 kg of seed on a plastic sheet and sprinkle the inoculant over; mix by hand until all seeds are covered.
l Reduce the amount of water and sugar proportionately to the amount of seed.
l The whole inoculant sachet can be used on less seed but NOT more than 100 kg.
l Inoculate seed in the shade; light and heat kill the live rhizobium cells.
10. Planting soyabeans
l Do not dry plant soya bean!
l Plant into moist soils.
l Hand planting: Using a row marker, cut shallow (3-4 cm) planting furrows into moist soil; dribble basal fertilizer (1 handful per 3-5 m); immediately dribble seed spaced at 5-7 cm.
Cover seed immediately to a depth of 2-3 cm (too deep poor germination) using a hoe, spike harrow or a tree branch drawn by oxen or tractor.
11. Weeding
l Remove all early weeds by hand-hoeing or use post-emergent herbicides.
l The second flush of weeds is usually smothered by the crop canopy closing.
12. Pests and diseases
l Soya bean is affected by very few pests and diseases.
l Leaf-eating semi-loopers can be controlled with Carbaryl, Monocrotophos or other insecticides.
l For Leaf Rust spray fungicide at flowering stage.
13. Harvesting soya bean.
l When mature leaves turn yellow and drop down; beans rattle sharply in the pods.
By hand: cut stems at soil level with hoe, sickle or pull out by hand early before 10am when pods are still moist to avoid shattering.
l Heap on a tarpaulin or other suitable surface; thrash with sticks when dry; or drive tractor, cart or oxen over heaped crop.
l If moisture content is high, spread beans out to dry for a few days.
l Combine Harvester: For large areas, use.
14. Marketing.
l Set aside quantities for home consumption and for seed.
l Balance can be sold to oil expressers or feed manufacturers or toll crushed to make own livestock feeds.
For more information: Contact your Farmers’ Union, AGRITEX, Input Suppliers or Prof S Mpepereki on 0772 220 934 or by e-mail:; or


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