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Local names in Kenya (Mahindi na Maharagwe, Oduma/Bando gi Oganda, Madumwa na Managanda)

Overview

Smallholder farmers commonly use maize and bean intercropping to increase soil nitrogen and enhance agricultural productivity. If intercropped, the choice of the legume intercrop should be based on presence of soil and climatic conditions that meet the requirements of both maize and the legume of choice. Maize-legume systems usually produce less maize than maize monoculture but provide higher economic returns. Higher land productivity makes maize-legume systems especially suitable for smallholders. Intercropping maize with legumes also increases land utility and regulates pests.

Site Selection
Select a site away from shade to allow for sufficient sunshine; and should be at least 10 meters away from the road to prevent dust and vehicle fumes

Altitude range

Intercrop require altitudes of 1000–2000 masl

Soil type and conditions

Well-drained loamy soils with pH of 5.5-6

Temperature range

The temperatures should be 15-27oC

Rainfall

The rainfall should be 500-1500 per growing period

Land Preparation
Consider minimum tillage to; reduce cost, conserve soil and water and nutrients reduce workload

Steps during land preparation.

  1. Slash and plant using appropriate tools
  2. Plough the soil using chisel ploughs to a medium tilth
  3. Hoes and oxen drawn implements can also be used
  4. 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
Pre-Planting
Certified or farmer saved seeds
  • Farmer saved seeds are alternatives where certified seeds are not available

 

  • Planting materials should be well-adapted to emerging local climatic and environmental conditions
Varieties
Select a suitable and well adapted variety. Sort out good seeds to ensure that they are free from insects, disease infestation and weed seeds
  • Select a variety adapted to low, medium and high altitude
  • Do not use damaged or wrinkled seeds, or seeds with holes
Planting
Plant at the onset of rains e.g. 4 continuous days of sufficient rain to take advantage of nitrogen flush and when the soil is moist

Planting Procedure

  • Plant along the contours across the slope
  • Conduct germination test before planting
  • Fill gaps one to two weeks after planting when plants have emerged. Under moist soil conditions 14 days after emergence
  • Thinning remove weak plants
  • Maize intercrop at a spacing of 90/75 cm x 50/60 cm depending on altitude
  • The seed rate is 2 per hole with double row beans or maize 90cm x 25/30 cm; 2 seeds per hole with beans double row at 30cm x 10/15cm; with single row beans
  • Maize inter-row of 75cm x 25/30cm with beans inter-row: 30cm x 10/15cm; 2-3 seeds per hole

Maize and beans intercrop

Water Management
It is uneconomical to irrigate maize unless in large parcels of land or in dry areas or dry seasons

Irrigation is an essential climate change adaptation practice under dry conditions but must observe efficient water-use and wise application to avoid leaching

  • Adopt more efficient micro-irrigation methods such as drip
  •  Irrigate fields early in the morning, late in the evening or at night but never during full sunshine 
  • Establish on-farm water harvesting capability and water storage capacity ditches, mulch or higher organic matter content 
  • Harvest water for a longer period than rainfall can maintain 
  • Apply water directly where it is consumed; drip irrigation or bottle solution for small fields
Weed Management
Weeding should be done early. After beans will spread to smoother the weeds

Apply integrated weed management to control weeds

Soil Fertility
Intercrop with nitrogen fixing leguminous species to increases nitrogen availability for maize
  • Test soils first to guide application of manure and fertilizer
  • Apply only deficient nutrients
  • Add manure and fertilizers to the soil in the right amounts to provide the required plant nutrients for vigorous crop growth.
Crop Management
Consider using minimum tillage to save on the costs of production
Consider using conservation farming approaches like minimum soil disturbance, permanent soil cover, crop rotation and soil conservation measures
 

Well managed maize and beans intercrop

 
Pest Management
Check for pests; use vector control or natural enemies e.g. aphids 

Pests include;

Fall Armyworm, Armyworm (Spodoptera exempta), maize stalk borer (Busseola fusca), termites, cutworms, leaf miner, moths, beetles, thrips, grasshopper, rodents (rats and mice), weevils (Sytophylus zeameis), larger grain borer (Prostephanus truncatus), African bollworm (Heliothis armigera), bean aphid (Aphis fabae), bean fly (Ophiomyia spp), flower thrips (Taeniothrips siostedti) and leaf miner

 

Fall Armyworm(Spodoptera frugiperda)

 

Bean fly

 

Maize stalk borer

 

African bollworm

Pests control strategies

  • Field and store hygiene, sanitation
  • Plant early and harvest early
  • Remove infected materials
  • Crop rotation or closed season
  • Push-pull technology
  • Use of natural enemies
  • Use of rat traps
  • Use of appropriate insecticides as recommended by experts
  • Use of Integrated Pest Management
  • Use of resistant varieties
  • Use clean planting material
  • Use of vector control or natural enemies e.g. aphids)
Disease Management
Check for disease; use appropriate fungicides as recommended by experts 

Diseases Include;

Head smut (Sphacelotheca reiliana), Smut (Ustilago maydis), Maize lethal necrosis disease (MLND), Maize streak virus, Northern leaf blight, Common rust, Grey leaf spot, 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)

 

Head smut

 

Bean anthracnose

Bean bacterial blight

 

Maize lethal necrosis disease (MLND)

Maize streak virus

 

Maize common rust

 

Bean common mosaic necrosis virus (BCMV)

Bean scab

 

Disease Management Strategies

  • Use of certified clean seed disease-free
  • Crop rotation and field hygiene
  • Use of resistant and tolerant varieties
  • Use of appropriate fungicides as recommended by experts
  • Remove diseased materials/plants
Maturity
Beans mature before maize 45 to 75 days after planting while maize takes 4 to 9 months after planting

Beans mature before maize 45 to 75 days after planting while maize takes 4 to 9 months after planting

Harvesting
Beans are harvested first before pods begin to shatter

Beans are harvested by cutting or uprooting the whole plant while maize is harvested by cutting and stalking to enhance drying and the de-husking Intercrop will produce about 1.9 tonnes per ha

Storage and Transportation
Sort then store in airtight bags or metallic silos

Sort then store in airtight bags or metallic silos

Post-Harvest Handling
Dry maize and beans to the required moisture content of 13-14%
  • Beans are dried, threshed and winnowed Re-drying of beans is done to attain storage moisture content level.
  • It is then sorted and stored
  • Maize are harvested after beans when they are mature then transported from the field to shelling house
  • Winnow to remove the chaff Control weevils, fungal infections e.g aflatoxin and grain borers by re-drying the maize to 13-14% moisture