Before focusing on specific crops, remember these key stages:

1. Planning — Decide what to grow, why, and for whom (market)
2. Site selection — Choose land with suitable soil, climate, and water access
3. Land preparation — Clear, plough, and prepare the seedbed
4. Selection of planting materials — Choose healthy, clean, and improved varieties
5. Planting — Sow or plant at the right time, depth, and spacing
6. Nutrient management — Apply fertilizers or manure to feed crops
7. Water management — Conserve soil moisture and provide irrigation when needed
8. Pest management — Control weeds, insects, diseases, and vermin
9. Harvesting — Collect produce at the right maturity stage
10. Post-harvest management — Clean, sort, grade, store, process, and market

Importance of Banana

Banana (Musa spp.) is a major food and cash crop in Tanzania. It provides carbohydrates, potassium, and vitamins A, B6, and C. The main varieties include Matooke, Uganda, Mchare, Kisukari, and improved types like TARIBAN 1-4.

Ecological Requirements

• Rainfall: 1,000–2,000 mm per year
• Temperature: 20–30°C
• Altitude: 0–2,000 m above sea level
• Soil: Deep, well-drained, loamy soil rich in organic matter; pH 6.0–7.5

Land Preparation

1. Clear bushes and weeds
2. Plough and harrow to 30–60 cm depth
3. Dig planting holes: 60 cm × 60 cm × 60 cm (or 90 cm × 90 cm × 90 cm in dry areas)
4. Mix topsoil with 20 kg compost and 200 g TSP per hole
5. Allow to settle for at least two weeks before planting

Planting Materials

Banana is propagated vegetatively using:

• Sword suckers — Narrow-leaved shoots about 1 m tall with 15 cm diameter
• Tissue culture seedlings — Disease-free plantlets from certified nurseries

Suckers should be trimmed, cut to clean white tissue, and dipped in hot water at 50–55°C for 20 minutes to kill nematodes and weevils.

Spacing

Water Management

Banana needs at least 1,000 mm rainfall annually. Use mulches to conserve moisture. Provide supplemental irrigation during dry seasons. Ensure proper drainage to avoid waterlogging.

Nutrient Management

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

Pest and Disease Management

Major pests: Nematodes, weevils, thrips Major diseases:

• Banana Bacterial Wilt (Ralstonia solanacearum)
• Bunchy Top Virus (BBTV)
• Black Sigatoka (Mycosphaerella fijiensis)
• Panama Disease (Fusarium wilt)

Control methods: Use clean planting material, remove infected plants, control insect vectors, apply appropriate fungicides, and maintain field hygiene.

Other Practices

• De-suckering: Remove excess suckers, keep only 3 per stool
• Propping: Support tall varieties with poles when bunches form
• De-leafing: Remove old or diseased leaves
• Bagging: Cover bunches with plastic bags to protect from insects

Harvesting and Post-harvest

Bananas mature 9–18 months after planting. Harvest when:

• Fruit size and length increase
• Cross-section changes from angular to rounded
• Peel colour changes from deep green to light green or yellow

Handle bunches carefully to avoid bruising. Clean, sort, grade, and pack in ventilated containers. Store at 13–14°C to extend shelf life.

Importance of Cassava

Cassava (Manihot esculenta) is an annual root crop providing cheap calories, fiber, vitamin C, and minerals. It is grown in Mwanza, Mtwara, Lindi, Shinyanga, Tanga, and coastal regions. Improved varieties include Mkombozi, Kiroba, Kizimbani, and TARICASS series.

Ecological Requirements

• Temperature: 25–29°C
• Altitude: 0–1,500 m
• Rainfall: 1,000–1,500 mm per year
• Soil: Well-drained sandy loam, pH 5.5–7.0

Land Preparation

1. Clear weeds and crop residues
2. Plough to 20–30 cm depth
3. Make ridges or mounds for planting
4. Space ridges 1 m apart

Planting Materials

Cassava is propagated from stem cuttings (20–30 cm long) taken from healthy, disease-free plants 8–12 months old. Store cuttings in shade for 2–3 weeks before planting.

Planting Procedure

1. Prepare ridges at 1 m × 1 m spacing
2. Insert cuttings at 45° angle, with 2 nodes buried and 2 above ground
3. Plant 5–10 cm deep
4. Water immediately if soil is dry

This gives 10,000 plants per hectare.

Water Management

Cassava tolerates drought but needs water for early growth. Provide supplemental irrigation in dry areas. Avoid waterlogging to prevent root rot.

Nutrient Management

• Apply organic manure (poultry manure, compost)
• Use NPK fertilizer based on soil test results
• Apply in three phases: 4–6 weeks, 10–12 weeks, and 16–20 weeks after planting

Pest and Disease Management

Pests: Cassava mealybug, green mites, whiteflies, variegated grasshoppers Diseases: Cassava Mosaic Disease (CMD), Cassava Brown Streak Disease (CBSD)

Control: Use disease-free planting material, rogue infected plants, rotate crops, control vectors, and apply recommended insecticides.

Harvesting

Harvest 8–18 months after planting when leaves turn yellow and begin to fall. Cut stems, loosen soil with hoe, and pull roots by hand. Avoid washing roots as moisture causes spoilage.

Post-harvest

Process quickly or store in cool, dry, ventilated place. Can be processed into flour, chips, or dried for longer storage.

Importance of Sweet Potato

Sweet potato (Ipomoea batatas) is a root crop grown for its starchy tubers and edible leaves. It is rich in vitamins and beta-carotene. Major producing regions: Shinyanga, Mara, Mwanza, Kagera, Kigoma, Tabora, Morogoro, Mbeya. Improved varieties include Kabode, Kakamega, Mataya, Kiegea, and Polista.

Ecological Requirements

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

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

Planting Materials

Use vine cuttings (15–50 cm long) from healthy, disease-free mother plants. apical cuttings from the vine tips are recommended as base cuttings may harbor weevils.

Planting Procedure

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

Water Management

Maintain consistent soil moisture, especially after planting. Use supplemental irrigation in dry periods. Avoid waterlogging.

Pest and Disease Management

Pests: Sweet potato weevils, white grubs, flea beetles Diseases: Sweet potato mild mottle virus, feathery mottle virus

Control: Use clean planting material, rotate crops, remove crop residues, harvest at maturity, and store in clean, ventilated places.

Harvesting

Harvest 90–120 days after planting when leaves turn yellow. Dig carefully using hand hoe or fork to avoid bruising tubers.

Post-harvest

1. Clean gently to remove soil (do not wash)
2. Cure in warm, humid place (26–29°C, 85–90% humidity) for 1–2 weeks
3. Grade by size and quality
4. Store in cool, dry place (13–16°C) with good ventilation

Importance of Round Potato

Round potato (Solanum tuberosum) is an annual tuber crop rich in starch, protein, and vitamin C. Grown in Southern Highlands (Mbeya, Iringa, Njombe), Kagera, Arusha, and Usambara mountains. Varieties include Asante, Sherehekea (table), Tengeru, Rumba (chips), and Markies (crisps).

Ecological Requirements

• Altitude: 1,200–2,700 m
• Temperature: 15–20°C
• Rainfall: 800–1,750 mm per year
• Soil: Well-drained, loamy, rich in organic matter; pH 5.5–7.0

Land Preparation

1. Clear field of weeds and residues
2. Till to 30–45 cm depth
3. Add well-rotted manure (25 tons/ha) if available
4. Create furrows 10–15 cm deep, 70 cm apart

Planting Materials

Use certified seed potatoes:

• Known variety (not mixed)
• Disease-free
• Size 35–45 mm (chicken egg size)
• Well-sprouted

Planting Procedure

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

Plant population calculation example:

Given: Spacing = 70 cm × 30 cm

$Plant population = \frac{Area}{Spacing} = \frac{10,000 m^2}{0.7 m × 0.3 m} = \frac{10,000}{0.21} = 47,619 plants/ha$

Water Management

Maintain consistent moisture, especially during tuber formation. Use drip, sprinkler, or furrow irrigation. Avoid waterlogging. Planting on mounds helps with drainage.

Nutrient Management

• Apply DAP (250–375 kg/ha) at planting
• Top-dress with CAN or urea later in growth cycle
• Apply muriate of potash if soil is low in potassium
• Use farmyard manure or compost to improve soil structure

Pest and Disease Management

Pests: Whiteflies, potato moths, nematodes Diseases: Late blight (Phytophthora infestans), early blight (Alternaria solani), bacterial wilt (Ralstonia solanacearum), viral diseases

Control: Use certified clean seeds, rotate crops, remove infected plants, apply fungicides preventively, control insect vectors, maintain field sanitation.

Harvesting

Harvest 3–4 months after planting when:

• Leaves turn yellow and dry
• Skin does not rub off easily
• Tubers separate easily from roots

Cut vines (dehaulm) two weeks before harvesting to harden skins. Harvest by hand or machine.

Post-harvest

1. Cure tubers under shade to heal minor injuries
2. Sort and grade by size and quality
3. Pack in nylon mesh bags for ventilation
4. Store in cool, dry, well-ventilated place

A farmer wants to plant cassava on a field measuring 50 m × 40 m.

Step 1: Calculate the area

$Area = 50 m × 40 m = 2,000 m^2$

Step 2: Convert to hectares (if needed)

$2,000 m^2 = 0.2 ha$

Step 3: Use recommended cassava spacing of 1 m × 1 m

$Plant population = \frac{Area}{Spacing} = \frac{2,000 m^2}{1 m × 1 m} = 2,000 plants$

So the farmer needs approximately 2,000 cassava cuttings for this field.

A Form 2 student from Mwanza whose family grows cassava and bananas can apply this knowledge by helping their parents select improved planting varieties (like TARIBAN banana or Mkombozi cassava), calculate proper spacing to maximize plant population, and identify common pests like cassava mealybugs or banana bunchy top disease. With this understanding, the family can increase their harvest from 10 to over 20 tonnes per hectare, earning more money at the local market — for example, selling 1,000 kg of cassava at TZS 500 per kg generates TZS 500,000 in income, which can pay school fees or invest in more crops.