Site Selection

Bananas grow best in:

• Deep, well-drained, loamy soils rich in organic matter
• Areas with annual rainfall of 1,000–2,000 mm
• Altitudes from sea level to 2,000 m above sea level
• Temperatures of 20–30°C
• Soil pH of 6.0–7.5

Avoid areas with strong winds that can damage the leaves and topple plants.

Land Preparation

1. Clear bushes and weeds from the field
2. Plough the soil to a depth of 30–60 cm
3. Harrow to break large soil clods
4. Dig planting holes measuring 60 cm × 60 cm × 60 cm (or 90 cm × 90 cm × 90 cm in dry areas)
5. Mix topsoil with 20 kg of manure/compost and 200 g of Triple Super Phosphate per hole
6. Allow the holes to settle for at least two weeks before planting

Planting

Selection of planting materials:

• Use sword suckers (narrow leaves, about 1 m tall, 15 cm diameter at base)
• Treat suckers by dipping in hot water at 50–55°C for 20 minutes to eliminate nematodes and weevils
• Alternatively, use tissue culture seedlings that are approximately 30 cm tall with at least five healthy leaves

Spacing:

• Short varieties: 3 m × 3 m (1,112 plants/ha)
• Medium varieties: 3 m × 4 m (833 plants/ha)
• Tall varieties: 4 m × 4 m (625 plants/ha)

Planting procedure:

1. Place the sucker or seedling in the centre of the hole
2. Cover the corm first with topsoil, then subsoil
3. Plant 30 cm deep and firm the soil
4. Apply thick mulch around each plant
5. Plant at the start of the rainy season

Water Management

• Bananas need minimum 1,000 mm rainfall per year
• Use mulches to conserve soil moisture
• Provide supplemental irrigation during dry spells
• Drain excess water to prevent waterlogging

Nutrient Management

• Apply NPK fertilizer (e.g., 20-20-20 or 8-10-10) at 250 g per plant twice yearly
• Apply 20–40 kg of well-decomposed farmyard manure per stem annually
• Place fertilizer 60 cm away from the plant stem

Other Practices

De-suckering: Remove excess suckers every 45 days, leaving only three per stool (mother, daughter, and granddaughter plants)

Propping: Support tall varieties with poles when fruit bunches form

De-leafing: Remove old, damaged, or diseased leaves

De-budding: Remove the male bud after bunch formation to increase yield and reduce thrips

Bagging: Cover bunches with plastic bags to protect from insects and speed up maturation

Harvesting

Bananas are ready 9–18 months after planting. Signs of maturity include:

• Fruit size and length increase
• Fruits change from angular to rounded cross-section
• Peel color changes from deep green to light green or yellow

Cut the bunch from the pseudostem carefully to avoid bruising.

Site Selection

Cassava grows best in:

• Well-drained sandy loam soil
• Soil pH of 5.5–7.0
• Temperatures of 25–29°C
• Altitudes of 0–1,500 m above sea level
• Annual rainfall of 1,000–1,500 mm

Land Preparation

1. Clear the site of weeds and debris
2. Plough to 20–30 cm depth
3. Form ridges or mounds for planting
4. Space ridges 1 m apart

Selection of Planting Materials

• Choose healthy, disease-free plants 8–12 months old
• Select stems 2–3 cm in diameter
• Cut stems into cuttings 20–30 cm long
• Store cuttings in a cool, shaded place for 2–3 weeks before planting

Planting

1. Plant cuttings on ridges or mounds at 1 m × 1 m spacing
2. Insert cuttings at 45° angle with 2 nodes buried and 2 nodes above ground
3. Plant 5–10 cm deep
4. Water immediately if soil is dry
5. Cuttings sprout within 1–2 weeks

Water Management

• Cassava tolerates drought but needs water for early growth
• Provide supplemental irrigation during prolonged dry spells
• Ensure good drainage to prevent root rot

Nutrient Management

• Apply organic manure (poultry manure, cow dung, compost)
• Use NPK fertilizer with micronutrients (boron and zinc)
• Apply one-third of fertilizer at 4–6 weeks, second at 10–12 weeks, and third at 16–20 weeks after planting

Weed Management

• First weeding at 3–4 weeks after planting
• Second weeding at 8 weeks
• Third weeding at 12 weeks
• Final weeding at 20–24 weeks

Harvesting

Cassava matures 8–18 months after planting. Harvest by:

1. Cutting stems to 30–50 cm height
2. Loosening soil with hoe or spade
3. Pulling roots by hand
4. Trimming roots from stems

Site Selection

Sweet potatoes thrive in:

• Well-drained sandy loam or loamy soil
• Soil pH of 5.5–6.5
• Temperatures of 24–35°C
• Rainfall of 500–900 mm during growing season

Land Preparation

1. Clear vegetation and weeds
2. Plough to 20–25 cm depth
3. Form ridges 20–25 cm high, 30–40 cm wide, spaced 90–120 cm apart

Selection of Planting Materials

• Use apical cuttings (young vines) 15–50 cm long
• Avoid base cuttings that may harbor weevils
• Use disease-free planting materials from reliable sources

Planting

1. Collect cuttings from healthy mother vines
2. Insert cuttings 7.5–10 cm deep into the ridge
3. Space plants 30–40 cm apart
4. Firm the soil around each cutting
5. Keep soil moist but not waterlogged

Water Management

• Maintain consistent soil moisture, especially after planting
• Use supplemental irrigation in dry areas
• Avoid waterlogging

Weed Management

• First weeding at 1–2 months after planting
• Use hand weeding or shallow cultivation
• Apply mulches to suppress weeds

Harvesting

Sweet potatoes mature 90–120 days after planting. Signs include:

• Leaves turning yellow
• Slightly weathered vine tips

Harvest carefully using a hand hoe to avoid bruising the tubers.

Site Selection

Round potatoes grow best in:

• Well-drained, loamy soil rich in organic matter
• Soil pH of 5.5–7.0
• Altitudes of 1,200–2,700 m above sea level
• Temperatures of 15–20°C
• Annual rainfall of 800–1,750 mm

Land Preparation

1. Clear the field
2. Till soil to 30–45 cm depth
3. Create a fine seedbed
4. Apply well-rotted manure (25 tons/ha) if available

Selection of Planting Materials

• Choose certified seed potatoes from reputable dealers
• Select uniformly sized tubers (35–45 mm, chicken egg size)
• Ensure seeds are well-sprouted and disease-free
• Varieties include Sagitta, Sherekea, Rumba, Panamera, and Markies

Planting

1. Open furrows 10–15 cm deep at 70 cm spacing
2. Apply planting fertilizer (DAP 250–375 kg/ha) in furrows
3. Cover fertilizer with thin soil layer
4. Place seed potatoes with sprouts facing up at 30 cm spacing
5. Cover with remaining soil
6. Irrigate if soil is dry

Plant population calculation example:

For a field with spacing of 70 cm between rows and 30 cm between plants:

$\text{Plant population per hectare} = \frac{10,000 \text{ m}^2}{0.70 \times 0.30 \text{ m}^2} = \frac{10,000}{0.21} = 47,619 \text{ plants/ha}$

Water Management

• Maintain consistent moisture, especially during tuber formation
• Use drip, sprinkler, or furrow irrigation
• Avoid waterlogging
• Plant on mounds to enhance drainage

Nutrient Management

• Apply DAP (250–375 kg/ha) at planting
• Top-dress with CAN or urea later in the growth cycle
• Apply potassium if soil is deficient
• Avoid excess nitrogen which promotes leafy growth at the expense of tubers

Weed Management

• First weeding at 3–4 weeks after planting
• Use hand hoe for weeding
• Avoid weeding after tubers begin to form to prevent damage

Harvesting

Potatoes are ready when:

• Leaves are dry and turned yellow
• Tuber skin does not rub off easily
• Tubers separate easily from roots

Harvest 3–4 months after planting, depending on variety. Dehaulm (cut vines) two weeks before harvesting to harden tuber skins.

A farmer in Mbeya wants to plant round potatoes on a 0.5 hectare plot. The recommended spacing is 70 cm between rows and 30 cm between plants.

Step 1: Calculate area per plant $0.70 \text{ m} \times 0.30 \text{ m} = 0.21 \text{ m}^2$

Step 2: Calculate total plants for 0.5 hectare $\text{Total plants} = \frac{0.5 \times 10,000 \text{ m}^2}{0.21 \text{ m}^2} = \frac{5,000}{0.21} = 23,810 \text{ plants}$

Step 3: Calculate seed requirement (at 2,500 kg/ha) $23,810 \div 47,619 \times 2,500 \text{ kg} = 1,250 \text{ kg of seed potatoes}$

A smallholder farmer in Mwanza can apply these husbandry practices to improve their banana and cassava production. For example, by properly selecting banana suckers, treating them with hot water, and planting at the correct spacing of 3m × 3m, a farmer can plant about 1,100 banana plants on one hectare instead of randomly planting 500 plants. This proper spacing can increase total bunch yield from 5 tonnes to over 10 tonnes per hectare, which at a market price of TZS 15,000 per bunch would generate TZS 15,000,000 instead of TZS 7,500,000 — nearly doubling the income from the same piece of land.