Overview
Beans (Phaseolus vulgaris) Local names in Kenya (Maharagwe, Oganda; Managanda)
Introduction
Beans is herbaceous annual plant grown for its edible dry seeds or unripe fruits. It is the second most important staple food after maize for the local people in Kenya. Its leaves are also used as vegetable and straw for animal fodder. In Kenya common beans are grown mainly for subsistence and for the local market. It is highly rich in protein hence known to be the cheapest source of protein, starch and minerals such as iron and potassium. Beans are cooked by boiling, frying, and baking or can be bought cooked or canned.
Altitude range
Beans require altitudes of altitude of 1000 – 2000 masl,
Soil type and conditions
Well-drained soils with a soil pH: 6.0 – 7.0.
Temperature range
The temperatures should be 20 – 30 oC optimal.
Rainfall
The rainfall should be 750 – 4000 mm p.a.
Steps during land preparation
- Slash and plant using appropriate tools e.g. rippers, jab planters, dibbler, oxen drawn equipment e.g. the ripper, tractor drawn no till planter
- Ploughing is done by preparing the soil using chisel ploughs to avoid fine tilths
- Hoes and oxen drawn implements can also be used
- Contour farming technique recommended
- Add manure and fertilizers to the soil in the right amounts to provide the required plant nutrients for vigorous crop growth
- Maintain soil health for good production and income
- Test soils first to guide application of manure and fertilizer
- Apply only deficient nutrients
- Consider using conservation farming approaches minimum soil disturbance, permanent soil cover, crop rotation, soil conservation measures
Common planting materials:
Seeds should be obtained from reliable sources. Farmer saved seeds are alternatives where certified seeds aren’t available or the seed can be bought from the market
Seeds
Recommended varieties :
- Select seeds that are adapted to local agro-ecological zones and from a recommended source
- Ensure the required variety
Geminating seed
Germinating seedlings
Plant at the onset of rains e.g. 4 continuous days of sufficient rain to take advantage of nitrogen flush
Plant along the contours or across the slope and when the soil is moist
Fill gaps one to two weeks after planting when plants have emerged
Thin to remove weak plants under moist soil conditions 14 days after emergence
Beans pure stand; seed rate 23kgs per acre; 2-3 seeds per hole at 25 by 60 cm or 15 by 25 cm depending on variety
Sort out good seeds to ensure that they are free from insects, disease infestation and weed seeds
Do not use damaged or wrinkled seeds, or seeds with holes
Planting bush beans in a monoculture on a flatbed is done by planting in rows which are 50 cm apart
Within a row, plant seeds at 8-10 cm apart (1 seed per stand) or 15-20 cm apart (2 seeds per stand)
Planting climbing beans: Plant climbing bean in rows which are 75 cm apart. Within a row, sow seeds 15 cm apart (1 seed per stand) or 25-30 cm apart (2 seeds per stand)
Climbing beans
- Apply water directly if necessary, to where it is consumed
- Use drip irrigation, bottle solution for small fields
Apply water daily in case of prolonged drought.
1st weeding is done 3-4 weeks after germination
2nd weeding is done just before topdressing
- Add manure and fertilizers to the soil in the right amounts to provide the required plant nutrients for vigorous crop growth
- Manure is to be applied based on soil test results at planting and at top dress. Use only non-acidifying fertilizers
- Note; Beans top dressing is not recommended given that it’s a leguminous crop that utilizes its fixed nitrogen in the soil
- Only replenish nutrients that test results show are needed for the right balance
Apply IPM principles for increased use of biophysical methods and reduced use of agrochemical methods to control weeds
Apply manure/boost soil fertility and also crop rotation
Pests include;
African bollworm (Heliothis armigera), Bean aphid (Aphis fabae), Bean fly (Ophiomyia spp), Flower thrips (Taeniothrips siostedti) and Leaf miner
They are controlled by field use of Integrated Pest Management (IPM), plant early or harvest early, rogueing, crop rotation, resistant varieties
Use of appropriate insecticides as recommended by experts
African Bollworm
Bean aphid
Bean fly
Flower thrips
Control of pests
Use Integrated Pest Management
Plant early and harvest early
Remove infected materials
Practice crop rotation
Use of resistant varieties
Use of appropriate insecticides as recommended by experts
Diseases include;
Root rots (Fusarium, Black), Leaf spots (Angular Phaeisariopsis griseola, Alternaria) Anthracnose (Colletotrichum lindemuthianum), Bean rust (Uromyces appendiculatus), Bacterial blight (Halo Pseudomonas phaseolus, Common Xanthomonas phaseoli, Ashy stem (Macrophomina phaselina), Bean common mosaic necrosis virus (BCMV), Bean scab (Elsione phaseoli) and White mould (Sclerotinia phaseoli)
Root rots (Fusarium, Black)
Leaf spots
Anthracnose
Bean rust
Bacterial blights (Halo and Common)
Bean Common Mosaic Necrosis Virus
Bean scab
Dry pods in the sun on clean mats, canvas or wire mesh trays on raised platform
Thresh an winnow to remove chaff and dust
Re-dry to attain storage moisture content level to maintain grain quality and to increase shelf life
Sort before storage to remove damaged, discolored and infected grains before storage.
Dry pods in the sun, thresh and winnow to remove chaff and dust, re-dry to attain storage moisture content level.
Use insecticides to preserve beans, store it in sisal or jute bags, on raised pallets to protect from rodents