Harvesting is a critical phase in horticultural production that directly affects the quality and market value of crops. In Kenya, where horticulture contributes significantly to both domestic supply and export earnings, efficient harvesting machinery plays a vital role in optimizing productivity and reducing post-harvest losses. This chapter focuses on the various types of harvesting machinery relevant to horticulture and their proper operation to ensure timely and quality harvest. Understanding these machines and their uses equips horticulture professionals to enhance farm efficiency and profitability.

5.1 Harvesting machinery

Harvesting machinery in horticulture and mixed farming includes the equipment used to cut, lift, pick, thresh or gather crops. The choice of machine depends on the type of crop, the scale of operation and the terrain. Many smallholder farms rely on hand tools or small machines, while large commercial farms and cooperatives invest in mechanised harvesters to meet market demand and improve labour efficiency.

5.1.1 Types of harvesting machinery

Harvesting machinery can be grouped by the crop it is designed to harvest and by how it works: cutting, lifting, picking, threshing or baling. Each type has features that suit particular products, so the operator must be able to recognise a machine and know what it is meant for. On a mixed horticultural farm, for example, a mower cuts the fodder grass, a baler packs it for storage, and a potato harvester lifts the root crop from the ridges.

5.1.1.1 Balers

A baler is a machine that picks up cut and dried forage or crop residue from the field and compresses it into compact bales tied with twine or net wrap. Baling reduces bulk so that hay, straw and haulms can be carried, stored and sold easily. Example: after a mower has cut Rhodes grass and it has dried in windrows, a tractor-drawn baler collects it and produces bales that are stacked in the farm hay store for dairy animals.

Main parts of a baler:

• Pick-up reel: Spring tines lift the windrow from the ground and feed it into the machine.
• Feeding mechanism: Forks, rotor or augers move the crop into the baling chamber in an even flow.
• Baling chamber: The space where the crop is compressed. In a rectangular baler a plunger packs it, and in a round baler belts or rollers roll it.
• Tying or wrapping unit: Knotters tie rectangular bales with twine, while round balers wrap with twine or net.
• PTO drive and drawbar: The tractor's power take-off supplies power to the machine, and the drawbar hitches it to the tractor.
• Bale ejector or tailgate: Releases the finished bale onto the ground or a bale chute.

5.1.1.2 Mowers

A mower is a machine that cuts standing grass, fodder crops or cover crops close to the ground. It is the first machine in the hay and forage chain, because the cut crop is left to dry before baling. Example: on a farm that grows Napier grass or Rhodes grass for dairy cows, a tractor-mounted drum mower cuts a large block in a few hours, a job that would take several workers a full day with sickles.

Main parts of a mower:

• Cutting unit: The knife, disc, drum, flail or blade assembly that actually cuts the crop.
• Frame and hitch: Connects the mower to the tractor's three-point linkage or drawbar.
• Drive system: Belts, gearbox and PTO shaft carry power to the cutting unit.
• Guards and shields: Cover the moving parts and stop stones and cut material from being thrown out.
• Height and lift controls: Adjust the cutting height and raise the unit for transport.

5.1.1.3 Combined harvesters

A combine harvester performs several harvesting operations in one pass: it cuts the crop, threshes it, separates the grain from the straw, cleans the grain and stores it in a tank. It replaces the separate cutting, carrying, threshing and winnowing jobs, so it saves labour and reduces field losses. Example: a self-propelled combine on a large farm harvests dry beans or wheat and unloads the clean grain straight into a trailer ready for the store.

Main parts of a combine harvester:

• Header: The front attachment that cuts and gathers the crop. Different headers are fitted for cereals, maize and other crops.
• Reel and cutter bar: The reel sweeps the crop onto the cutter bar, which cuts it.
• Feeder house: A conveyor that carries the cut crop to the threshing unit.
• Threshing cylinder and concave: Rub the grain or seed out of the heads, pods or cobs.
• Separating unit: Straw walkers or rotors separate the remaining grain from the straw.
• Cleaning unit: Sieves and a fan blow away chaff and light dirt from the grain.
• Grain tank and unloading auger: Store the clean grain and discharge it into a trailer.

5.1.1.4 Potato harvester

A potato harvester is a machine that digs potatoes out of the ridge, separates them from soil, stones and haulms, and delivers the tubers to a trailer or bunker. It lifts the whole crop in one pass, so it suits fields where the crop is ready at one time. Example: on a large potato farm a two-row harvester pulled behind a tractor lifts the tubers from two ridges at once, and workers on the sorting table remove stones and damaged tubers.

Main parts of a potato harvester:

• Digging share or blade: Cuts under the ridge and lifts the soil and tubers onto the elevator.
• Web elevator (conveyor chain): Open chain belts that carry the lifted material up and shake loose soil through the gaps.
• Haulm remover or rollers: Strip the remaining stems and weeds from the tubers.
• Agitator or stone and clod separator: Separates stones and soil clods from the tubers.
• Sorting table: Where workers remove damaged tubers and remaining foreign matter by hand.
• Bunker or loading elevator: Holds the tubers or loads them into a trailer alongside.

Care is needed in the design and setting of the machine because potatoes bruise easily, and bruised tubers store badly and sell at a lower grade.

5.1.1.5 Threshers

A thresher is a machine that separates grain or seed from the head, pod or cob, without cutting the standing crop. It is used after the crop has been cut and dried, and it replaces beating by hand or with sticks. Example: after bean plants have been harvested and dried, a portable thresher separates the seed from the pods and haulms, reducing the time and effort needed for post-harvest handling.

Main parts of a thresher:

• Feed hopper or tray: Where the crop is fed into the machine at an even rate.
• Threshing drum or cylinder: A rotating drum with bars, spikes or pegs that knocks the grain from the crop.
• Concave: The curved screen under the drum. The gap between it and the drum can be adjusted for different crops.
• Sieves and cleaning fan: Separate the grain from chaff and broken straw.
• Straw outlet and grain outlet: Discharge the straw and the clean grain separately.
• Power drive: Belt or PTO drive from a tractor, engine or electric motor.

Mechanical harvesters for fruits and vegetables

Mechanical harvesters are designed to pick fruits and vegetables with as little damage as possible. For instance, some berry harvesters use gentle shaking to detach fruit without bruising, and tomato harvesters use cutting and conveying systems.

• Selective harvesters: These machines pick only ripe produce, which is useful in crops that do not ripen uniformly. They reduce waste and improve quality by leaving unripe fruit on the plant.
• Non-selective harvesters: Used for crops such as carrots or onions where the whole crop is harvested at once. These machines dig or lift produce from the soil.
• Conveyor-based systems: Many mechanical harvesters use conveyors to carry produce from the field to collection bins, reducing manual handling and damage.
• Self-propelled harvesters: These combine harvesting and transport, improving efficiency on large farms.
• Tractor-mounted harvesters: Attachments fitted to tractors for harvesting specific crops such as maize or onions, offering versatility on medium-scale farms.

Handheld and semi-mechanical harvesting tools

For small horticultural farms, handheld and semi-mechanical tools remain essential because they allow precise picking and cause little damage to the crop.

• Harvesting knives and sickles: Used to cut vegetables, cereals and fodder by hand. They need to be kept sharp for a clean cut.
• Pruning shears: Used for fruit, flowers and shrubs where a clean cut protects the plant.
• Mechanical pruners: Battery-powered or manual pruners used for crops such as tea or cut flowers to increase speed and reduce fatigue.
• Harvesting bins and trolleys: Semi-mechanical aids for collecting and moving produce within the farm, saving time and labour.
• Field crates and baskets: Hold the picked produce and protect it from crushing until it reaches the packing area.

Specialty harvesters for specific crops

Certain horticultural crops need specialised machinery because of their particular harvesting requirements.

• Tea plucking machines: Mechanical pluckers cut the tender shoots of tea bushes, increasing plucking speed on large estates while keeping leaf quality acceptable.
• Flower harvesters: Machines that cut and bundle flowers on large floriculture farms, where speed and uniform stem length matter.
• Citrus harvesters: Machines that shake trees gently or use picking arms to remove fruit without damaging branches or fruit.
• Onion lifters: Loosen and lift bulbs from the soil and lay them in rows to dry.
• Bean and pea harvesters: Cut or pull the plants and strip the pods, so that the crop is gathered in one operation.

Equipment for post-harvest handling

Harvesting often links with the first post-harvest steps so that produce quality is maintained.

• Cleaning machines: Remove soil and debris immediately after harvest.
• Sorting and grading machines: Classify produce by size or quality, which is important in packing houses.
• Weighing and packing equipment: Weigh produce and fill crates or cartons to a set mass.
• Conveyors and elevators: Move produce between machines with little handling and damage.
• Cooling equipment: Not harvesting machinery in itself, but cooling units fitted to transport vehicles help preserve freshness on the way to the store or market.

Chapter Summary

This chapter provided a comprehensive overview of harvesting machinery, detailing the various types such as balers, mowers, combined harvesters, potato harvesters, and threshers. It explored their specific uses and operational procedures, emphasizing how each machine contributes to efficient crop harvesting on the farm. The chapter also highlighted critical maintenance practices including servicing, repair, and proper storage to ensure the longevity and reliability of harvesting equipment. Practical guidance was given on operating each type of machinery safely and effectively, with attention to the unique features of balers, mowers, combined harvesters, potato harvesters, and threshers. The importance of regular maintenance was reiterated to prevent breakdowns and maximize productivity. Overall, the chapter equipped learners with both theoretical knowledge and practical skills necessary to manage harvesting machinery efficiently in a farming context.