Maize - Beans Intercrop

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 15-27^oC

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.

Slash and plant using appropriate tools
Plough the soil using chisel ploughs to a medium tilth
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

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

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

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

Maize - Beans Intercrop

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