In Summary
  • Most farmers weed their fields once and some twice but it is advisable to maintain the farm weed free at all times to maximize yield.
  • The climbing bean varieties grown in western Uganda and on the slopes of Mountain Elgon are Nabe12C, 26C, 17C and 29C including Narobean 4C and 5C.

Common beans grow well on more productive types of soils. They are, however, most frequently grown on low yielding soils but areas with annual rainfall of 400mm are 1,200mm mm are recommendable. Climbing beans grow well in high altitude areas mainly in the western region and Mt Elgon region of Uganda.
Soils with median soil pH between 5.0 and 6.0 are recommended. Phosphorus is the most frequent deficient soil nutrient; soil nitrogen is also often limiting.
The head of the bean programme at the National Crop Resources Research Institute, Dr Stanley Nkalubo with an expertise in breeding the crop gives excerpts about best practices farmers growing beans can adopt to get improved yield.

Soil preparation
Dr Nkalubo explains that soil preparations should start before the first rains in order to provide appropriate conditions for seed germination and plant development, including air circulation, improved infiltration, soil temperatures as well as for weed control.
It is important to prepare a good seedbed where all the trash must be removed and disposed. It must not be burnt or left to rot in the field because this will cause spread of diseases

Seed selection
Farmers should choose cultivars for which there is a market. Select the best variety and do the seed selection too.
It is important that you verify seed quality, consulting seed inspection services.
It is important to source good seed with 90 per cent germination capacity, it must have uniform colour and seed volume.
Seed rates vary from 20 to 30 kilogrammes per acre and a farmer who adopts the right agronomy practice will harvest between 450 to 600 kilogrammes per acre.

Diseases
Angular leaf spot, it affects the foliage and pods of beans in the field during the growing season. All parts above the ground are susceptible.
Leaf Rust which affects leaves and sometimes stems and pods. The first symptoms appear on the undersurface of leaves as tiny, white, raised spots.
These spots gradually enlarge and form reddish-brown pustules that erupt to release rusty masses of spores.
Anthracnose spread through seed, air and water. It can affect all the above-ground tissues of the bean plant.

Pests
The pests include bean stem maggot, bruchid, caterpillars and bean weevils which feed on the leaves and stems causing damage to the plant. Bean weevils also feed on seeds after harvesting.

Control
Farmers are advised to apply appropriate pesticide as per directives from the manufacturer. Dr Nkalubo and his team offer four ways of control.
•Farmers must apply fungicide commonly known as ridomil in their farms two weeks after planting to avoid destruction from pests.
•Application of folia fertiliser also helps against pest and disease incidences.
•Crop rotation and intercropping beans with crops such as maize, sorghum and others is important in controlling some of the soil borne diseases
•Seeds should be treated with streptomycin or substitute. It is important to plant disease free seeds which farmers are expected to purchase from certified seed companies.

Harvesting
•At maturity a farmer can harvest green pods and sell the product fresh or wait for the crop to dry to process grains.
•It is important to observe when the pods are yellow to start harvesting. Farmers are advised not to wait for the pods to dry completely in the field. There will be a challenge of weevil infestation and loss of grains.
•Pod harvest from the field should be done early morning, because as temperature rises the pods become very dry and pods can open when removing from the shoots and let the grains fall into the ground.
•The harvested plants should be left to dry using polythene papers, or cemented drying yards.

Planting
Farmers must plant the seed in rows or blocks and the right spacing is 50cm by 10cm or six inches between each seed.
Plant the seeds two inches deep into the soil and cover it with the soft surface soil. If possible, let the seed eyes face the ground.
Under normal circumstances and ideal conditions, bean would begin to sprout with six days of planting and grow into a good sprout within two weeks.

The recommended seed varieties for common beans which are grown in the central, eastern and northern regions are the Nabe series 4, 15 – 21 and Narobean 1, 2 and 3 varieties. These are obtained from certified seed companies and at NaCRRI.
The climbing bean varieties grown in western Uganda and on the slopes of Mountain Elgon are Nabe12C, 26C, 17C and 29C including Narobean 4C and 5C. These bean varieties can be obtained from Kachwekano Zonal Research and Development institute (KAZARDI) in Kabale and NaCRRI in Namulonge.

Maintenance
When soils are fertile, fertiliser application is not required but for soils which lack fertility, farmers are advised to apply 50 kilogrammes of diammonium phosphate (DAP) using the broadcasting method per acre.
Farmers are obliged to apply inorganic fertiliser such as manure which must not contain pests and maggots because they may end up destroying the plant.

Weeding
Most farmers weed their fields once and some twice but it is advisable to maintain the farm weed free at all times to maximize yield.
Bean farms can be intercropped with maize, sunflower and sorghum among others but a farmer should make sure the other crop species should not outgrow the beans.