Grade 10 Agriculture : Crop Production – General Crop Harvesting Notes

Agriculture — Crop Production

Specific Learning Outcomes

Explain factors that determine when and how to harvest a crop produce.
Carry out harvesting processes for selected crops (simple practical steps and safety).
Acknowledge the importance of correct harvesting and post‑harvest handling in crop production.

Key terms (short)

Maturity: When a crop is ready for harvest (physically and physiologically).
Threshing: Removing grain/seed from the plant or pod.
Winnowing: Separating grain from chaff using wind or a fan.
Post‑harvest handling: Drying, cleaning and storing to keep quality and reduce loss.

Factors that determine harvesting (what farmers check)

Crop maturity signs: colour change of leaves/pods, dry husks (maize), eye formation in tubers (potatoes), dry pods (beans).
Moisture content: Harvest when grain moisture is low enough for safe storage (e.g., maize ~13–14%); otherwise dry soon after harvest.
Weather: Harvest in dry days to reduce rotting and allow sun‑drying. Avoid harvesting in heavy rains.
Pest and disease pressure: If pests/diseases attack, harvest early to save most of the crop and reduce losses.
Labour and tools availability: Enough people and proper tools (panga, sickle, tarpaulin, sacks) affect timing and method.
Market demand and prices: Farmers may time harvest for better prices, but must balance with storage risks.
Storage facilities: If good storage exists (PICS bags, granaries), grain can be stored; if not, sell or process soon.
Seed saving needs: If keeping seed, harvest at proper maturity and select healthy plants.

(sun = dry weather, tools, store)

Harvesting processes — simple step‑by‑step (common Kenyan crops)

Maize (corn)

When to harvest: Husk dry, silk brown and dry, kernels hard and give a rattling sound in the cob.

Lay tarpaulin on ground to keep cobs clean.
Use hands or panga to remove cobs from stalks (cut or twist). Avoid injuring grain.
Dry cobs in sun for 3–7 days, turning often until kernels are hard (dry out quickly on dry days).
Thresh: remove kernels by hand, with a stick on a mat, or using a simple local thresher.
Winnow to separate chaff (use wind, fan, or winnowing basket).
Dry kernels to safe moisture (~13–14%) before storage (use tarpaulin, solar dryer or under shade with good ventilation).
Store in clean sacks or hermetic bags (PICS), off the ground, and protect from rodents/maize weevils.

Safety & tips: Wear gloves when using pangas; dry quickly to prevent aflatoxin from poor drying.

Common beans

When to harvest: Leaves yellowing and pods dry and brown; seeds rattle inside pods.

Pull or cut whole plants and lay on tarpaulin to dry (or harvest pods directly if only a few).
Allow to dry in sun until pods are brittle (2–5 days depending on weather).
Thresh by beating on a mat or by hand to free the beans.
Winnow to remove chaff and dust.
Sort out broken or discoloured seeds (keep healthy ones for seed if needed).
Store in moisture‑proof containers or hermetic bags to prevent insects and mould.

Safety & tips: Harvest early in the morning if dew is heavy; dry fully before storage to avoid mould.

Irish potatoes (seed and ware)

When to harvest: For eating: tops yellow and die back; for seed: when tubers have firm skins (a few weeks after vines die).

Loosen soil carefully with fork or jembe to avoid cutting tubers.
Lift tubers gently and brush off excess soil (do not wash if storing long term).
Cure in a cool, shaded, well‑ventilated place for 7–14 days to toughen skins.
Store in a dark, cool place with ventilation (avoid direct sun to prevent greening and solanine formation).

Safety & tips: Do not store potatoes near onions or apples (they change sprouting and spoilage patterns).

Why correct harvesting and handling matters

Reduces post‑harvest losses (rot, pests, insects) — more food for the family and marketable produce.
Improves quality and price of produce — clean, well‑dried grain sells better at market.
Protects health — prevents toxin formation (e.g., aflatoxin in poorly dried maize).
Allows seed saving — healthy seeds give next season’s good crops.
Increases income and food security for households and communities.

Suggested learning experiences (practical and classroom)

Field practical: Visit a local smallholder farm during harvest time (maize/beans) — students observe, help harvest and practise threshing and winnowing.
Class demonstration: Teacher brings sample cobs, pods and tubers. Students check maturity signs: break a maize kernel, open a bean pod, inspect potato skin.
Group activity: Each group practices sun‑drying grain on tarpaulin and records drying time, weather and moisture change (simple comparative study).
Experiment: Compare stored grain in ordinary gunny bags vs hermetic PICS bags for 2 months and record insect damage and weight loss.
Role play: One student plays a farmer deciding when to harvest given weather, pests, labour and market price scenarios; class discusses best choice.
Create posters showing step‑by‑step harvest and storage methods for maize, beans or potatoes (use local language if desired).
Assessment: Short practical test — correctly demonstrate threshing and winnowing; written questions on factors determining harvest time.

Teacher notes & resources

Use locally available tools (panga, sickle, tarpaulin, baskets) to make demonstrations realistic.
Invite a local farmer or extension officer to explain community practices and pests (e.g., storage pests in Kenya like maize weevil).
Use simple measuring tools: kitchen moisture meter or compare weight before and after drying to show moisture loss.
Discuss seasonal calendars in Kenya (long rains March–May, short rains Oct–Dec) to plan harvests.
Emphasise safety (cutting tools) and hygiene (clean storage containers) at all times.

Student harvest checklist (quick)

⭐ ⭐ ⭐ ⭐ ⭐