Unit 6: Production Technology of Plantation Crops - Subjective Questions

Climatic requirements:

• Tea requires a warm, humid, frost-free climate.
• An optimum temperature range of about – promotes continuous shoot growth. Temperatures below slow growth, while excessive heat causes scorching and moisture stress.
• Well-distributed annual rainfall of approximately – is desirable.
• High relative humidity, frequent showers, mist and morning dew encourage the production of tender shoots.
• Tea can be grown from near sea level to elevations above . High-elevation tea generally grows slowly but develops superior aroma and quality.
• Strong winds, hail, drought and prolonged waterlogging are harmful. Windbreaks and shade trees are therefore useful.

Soil requirements:

• Deep, well-drained, friable loam rich in organic matter is ideal.
• Tea is an acid-loving crop and performs best at a soil pH of about –.
• The soil should have good moisture-holding capacity but must not remain waterlogged.
• A minimum effective soil depth of about is preferred for unrestricted root development.
• Heavy clay, saline, alkaline and calcareous soils are unsuitable.
• On slopes, contour planting, terraces, drains and vegetative barriers are required to reduce erosion.

Propagation:

• Tea may be propagated by seed or vegetative methods.
• Seed propagation produces genetically variable plants and is mainly used for breeding or raising seedling populations.
• Commercial plantations generally use single-node leafy cuttings from selected high-yielding clones.

Nursery raising:

1. Healthy shoots of pencil thickness are selected from mother bushes.
2. Single-node cuttings, each carrying one healthy leaf and an axillary bud, are prepared.
3. Cuttings are planted in polythene sleeves containing acidic, well-drained nursery soil.
4. The nursery is maintained under partial shade and high humidity.
5. Regular watering, hardening, weeding and plant-protection measures are provided.
6. Rooted plants are gradually exposed to field conditions before planting.

Field establishment:

• Land is cleared without causing severe soil erosion, and drainage channels are prepared.
• On slopes, planting is done along contours or terraces.
• Pits or trenches are filled with topsoil and well-decomposed organic matter.
• Common spacing systems include approximately or other paired-row and hedge systems suited to local conditions.
• Planting is normally undertaken at the beginning of the rainy season.
• Young plants are mulched, protected from wind and supplied with temporary shade.
• Infilling of gaps is carried out early to obtain a uniform stand.

Objectives:

• To develop a low, broad and convenient plucking table.
• To maintain a balance between vegetative growth and shoot harvest.
• To remove dead, diseased, weak and unproductive wood.
• To rejuvenate bushes and sustain yield and quality over many years.

Training young tea:

• Young plants are subjected to centering, in which the main stem is cut to promote lateral branches.
• Secondary branches may be tipped or bent outward to develop a spreading frame.
• Repeated tipping creates a flat and dense plucking surface.

Pruning:

• Light pruning removes the upper wood and renews the plucking surface.
• Medium or deep pruning is adopted when bushes become tall or unproductive.
• Rejuvenation pruning cuts old bushes low to rebuild their framework.
• Pruning is followed by sanitation, wound protection where necessary, manuring and a recovery period.

Plucking:

• The standard unit is usually two leaves and a bud, although finer or coarser standards may be used.
• Plucking rounds are commonly maintained at intervals of about – days, depending on season and growth.
• Fine plucking produces better-quality tea, while coarse plucking may increase bulk but lowers quality.
• Plucking should preserve enough maintenance foliage below the plucking table for photosynthesis.

Manufacture of black tea:

1. Plucking: Tender shoots, generally two leaves and a bud, are harvested.
2. Withering: Leaves are spread in troughs and exposed to controlled air. Moisture is reduced, and the leaves become soft and pliable.
3. Rolling or CTC: In orthodox manufacture, leaves are rolled to twist and rupture cells. In CTC manufacture, they are crushed, torn and curled into small particles.
4. Oxidation: The ruptured leaf enzymes react with polyphenols in the presence of oxygen. This stage, traditionally called fermentation, develops coppery colour, briskness and characteristic aroma.
5. Firing or drying: Hot air stops oxidation and reduces moisture to a safe level, generally around –.
6. Sorting and grading: Dried tea is separated according to particle size and grade.
7. Packing: Tea is packed in moisture-proof and odour-proof containers.

Green tea manufacture:

• Fresh leaves are rapidly steamed or pan-fired to inactivate polyphenol oxidase.
• The leaves are then rolled, shaped, dried, graded and packed.
• Enzymatic oxidation is deliberately prevented.

Major differences:

• Black tea: Fully oxidized; dark liquor; stronger, brisk flavour.
• Green tea: Unoxidized; greenish liquor; fresher and more vegetal flavour.
• Black tea quality depends heavily on controlled oxidation, whereas green tea quality depends on rapid enzyme inactivation and retention of green colour.

Arabica is preferred for premium-quality beverages, whereas Robusta is widely used in instant coffee and espresso blends to improve body, crema and strength.

Climate:

• Coffee requires a warm, humid climate with a distinct dry period for blossom initiation.
• Arabica prefers cooler highlands, whereas Robusta performs well under warmer and more humid conditions.
• Annual rainfall of about –, when well distributed, is generally suitable.
• Blossom showers initiate flowering, while backing showers support fruit set and development.
• Frost, hot desiccating winds, prolonged drought and waterlogging are harmful.

Soil:

• Deep, well-drained, slightly acidic loam rich in humus is preferred.
• A pH of approximately – is suitable.
• The soil must permit deep rooting and should possess good moisture-holding capacity.

Propagation:

• Coffee is commonly propagated through seed obtained from healthy, high-yielding plants.
• Selected seed is sown in raised primary nursery beds, often with the flat side downward.
• Seedlings at the button or early leaf stage are transplanted into secondary beds or polythene bags.
• Vegetative propagation through cuttings or grafting is useful for maintaining selected clones, especially in Robusta.

Planting:

• Pits are prepared and filled with topsoil and organic manure.
• Spacing varies according to species, cultivar, slope and training system; Arabica is generally planted closer than Robusta.
• Planting is done during the rainy season.
• Shade trees, windbreaks, contour drains and mulch are established as required.

Shade regulation:

• Coffee is commonly grown under a two-tier shade canopy.
• Temporary or lower shade protects young plants, while permanent upper-storey trees provide long-term filtered shade.
• Excessive shade promotes weak growth and diseases; insufficient shade causes heat stress, overbearing and dieback.
• Shade trees should be periodically lopped before the rainy season.

Irrigation:

• Irrigation is particularly useful during dry periods.
• Blossom irrigation is given after a dry spell to induce uniform flowering.
• Backing irrigation is given after flowering to support fruit set and prevent flower abortion.
• Drip or sprinkler systems can be used depending on water availability and terrain.

Nutrition:

• Fertilizer application should be based on soil, leaf analysis, age and expected yield.
• Nitrogen supports vegetative growth, phosphorus promotes roots, and potassium improves berry filling and stress tolerance.
• Fertilizers are generally applied in split doses around the root zone.
• Organic manure, compost, lime or dolomite may be added according to soil requirements.

Training and interculture:

• Topping limits plant height and facilitates harvesting.
• Excess suckers, dead wood and crossing branches are removed.
• Weeds are managed by slashing, mulching, cover crops or careful herbicide use.
• Contour drains, terraces and cover vegetation minimize runoff and soil erosion.

Harvesting:

• Only ripe, red cherries should preferably be picked.
• Green, overripe, dried and damaged berries are separated because they lower beverage quality.

Wet method or washed coffee:

1. Ripe cherries are sorted, often using water flotation.
2. The outer skin and most pulp are removed in a pulper.
3. Parchment coffee is fermented to break down the mucilage.
4. The fermented parchment is thoroughly washed.
5. It is dried uniformly to a safe moisture content of about –.
6. Dry parchment is hulled to remove the parchment layer.
7. Beans are graded, polished where required and stored.

The wet method produces clean, bright and high-quality coffee but requires more water, equipment and careful effluent management.

Dry method or natural coffee:

1. Whole ripe cherries are cleaned and spread on drying yards, mats or raised beds.
2. Cherries are turned frequently to ensure even drying and prevent mould.
3. Drying continues until a safe moisture level is reached.
4. The dried husk, pulp and parchment are removed together by hulling.
5. Beans are cleaned, graded and stored.

The dry method is simpler and uses less water, but poor drying can cause fermentation, mould and undesirable flavours.

Storage:

• Coffee should be stored in clean, dry, cool and well-ventilated conditions.
• Bags must be kept on pallets away from walls, moisture and strong odours.

Climate:

• Cocoa is a tropical crop requiring a warm, humid and equable climate.
• A temperature range of approximately – is favourable.
• Well-distributed annual rainfall of about – is preferred.
• Young cocoa plants require shade and protection from strong wind.
• Drought, low humidity and prolonged waterlogging reduce growth and pod production.

Soil:

• Deep, fertile, well-drained loam rich in organic matter is ideal.
• A soil depth of at least – encourages strong root development.
• Slightly acidic to near-neutral soils, generally around pH –, are suitable.
• Heavy waterlogged, saline and very shallow soils should be avoided.

Propagation:

• Cocoa is propagated by seed, budding, grafting or rooted cuttings.
• Seeds are recalcitrant and should be sown soon after extraction from ripe pods.
• Vegetative propagation maintains desirable characters of elite clones.

Planting:

• Healthy seedlings or grafts are planted at the beginning of the rainy season.
• A spacing of about is commonly adopted, but it may vary with the production system.
• Pits are filled with topsoil and decomposed organic manure.
• Cocoa is often grown under coconut, arecanut or suitable shade trees.
• Irrigation, mulching and temporary shade are provided during establishment.

Canopy management:

• A cocoa seedling normally forms a jorquette, where the upright stem divides into fan branches.
• The jorquette is maintained at a convenient height, and about three to five well-spaced fan branches are retained.
• Unwanted vertical shoots called chupons are removed regularly.
• Dead, diseased, crowded, crossing and low-hanging branches are pruned.
• Moderate pruning improves light penetration, aeration, spraying and harvesting.

Shade regulation:

• Young cocoa requires relatively heavy shade to avoid sun scorch and moisture loss.
• Shade is gradually reduced as plants mature.
• Excessive shade leads to poor flowering, high humidity and disease, while insufficient shade causes heat and drought stress.
• Temporary shade plants and permanent upper-storey trees may be used.

Nutrition:

• Nutrient application should be based on soil tests, leaf analysis, tree age and yield.
• Nitrogen supports canopy growth, phosphorus promotes roots, and potassium is essential for pod and bean development.
• Organic manure, compost and retained leaf litter improve soil structure and microbial activity.
• Fertilizers are applied in split doses in a ring beneath the canopy.

Irrigation and soil management:

• Irrigation is required during prolonged dry periods, especially during flowering and pod development.
• Drip irrigation improves water-use efficiency.
• Mulching, cover crops, drainage and weed control help conserve soil moisture and maintain root health.

Harvesting:

• Mature pods are identified by a characteristic colour change.
• Pods are cut carefully with a knife or harvesting tool without injuring flower cushions, because future flowers arise from the same cushions.
• Diseased and damaged pods are separated.
• Pods are opened without cutting or crushing the beans.

Fermentation:

1. Wet beans with adhering pulp are placed in heaps, baskets, boxes or trays.
2. The mass is covered with leaves or sacks to conserve heat.
3. Beans are turned periodically to improve aeration and uniformity.
4. Fermentation generally continues for several days, depending on genotype and method.

Fermentation kills the embryo, removes mucilage, reduces bitterness and astringency, and forms precursors of chocolate flavour and brown colour. Under-fermentation produces slaty, bitter beans, whereas over-fermentation may cause off-flavours and deterioration.

Drying:

• Fermented beans are sun-dried on clean floors or raised trays, or dried carefully in mechanical dryers.
• Beans are turned frequently for uniform drying.
• Moisture is reduced gradually to about – for safe storage.
• Rapid overheating creates smoky or acidic flavours, while slow drying encourages mould.

Grading and storage:

• Beans are cleaned and graded based on size, fermentation, mould, insect damage and foreign matter.
• A cut test may be used to assess internal colour and fermentation.
• Dried beans are packed in clean bags and stored in a cool, dry, odour-free and well-ventilated place.

Flowering and fruiting behaviour:

• Cocoa is cauliflorous; flowers arise on cushions located on the main trunk and older branches.
• Flowers are small, structurally complex and are mainly pollinated by tiny midges.
• Although a mature tree may produce thousands of flowers, only a small proportion develops into mature pods.
• Pollination failure, self-incompatibility in some genotypes, nutrient deficiency and adverse weather can limit fruit set.
• Young fruits that cease growth and dry naturally are called cherelles, and their loss is known as cherelle wilt.
• Pods require several months to reach maturity, depending on genotype and environment.

Measures to improve production:

• Grow compatible, high-yielding clones or seedling mixtures to improve cross-pollination.
• Maintain a moist, organic plantation floor that supports pollinating midges.
• Regulate shade to provide adequate light without exposing trees to excessive heat.
• Supply balanced nutrients and irrigation during flowering and pod development.
• Avoid excessive pruning and injury to flower cushions.
• Remove diseased and mummified pods through frequent sanitation rounds.
• Manage black pod disease, pod borers, mirids and rodents using integrated methods.
• Harvest mature pods regularly to reduce pest and disease carryover.

Climate:

• Cashewnut is a tropical crop adapted to warm conditions, with optimum growth commonly occurring around –.
• It grows in areas receiving about – of annual rainfall.
• A distinct dry period during flowering and nut development favours good fruit set.
• Frost, waterlogging, cloudy weather and rain during flowering are harmful.
• The crop tolerates drought after establishment but is sensitive to strong coastal winds and prolonged flooding.

Soil:

• Cashew can grow on lateritic, sandy and relatively poor soils where many crops perform badly.
• Best production is obtained in deep, well-drained soils without a hardpan.
• Saline, alkaline and waterlogged soils are unsuitable.

Propagation:

• Seed propagation causes considerable variability and is mainly used to raise rootstocks.
• Commercial orchards should use softwood grafts, epicotyl grafts or other true-to-type planting material from elite mother trees.

Planting:

• Land is cleared, laid out and protected against soil erosion.
• Pits are filled with topsoil and decomposed organic manure.
• A common spacing is about or , although high-density systems may use closer spacing initially.
• Grafts are planted at the onset of monsoon without burying the graft union.
• Staking, mulching, irrigation and replacement of dead plants are important during establishment.

Training and pruning:

• Young grafts are trained to develop a single stem up to about –.
• Rootstock sprouts and shoots arising below the graft union are removed.
• Three to five well-spaced scaffold branches are retained to form a broad canopy.
• Criss-cross, crowded, dead, diseased and ground-touching branches are removed.
• Heavy pruning should be avoided because cashew bears on the current season's terminal shoots.

Nutrient management:

• Well-decomposed farmyard manure or compost is applied to improve soil organic matter.
• Nitrogen, phosphorus and potassium are supplied according to tree age, soil-test values and regional recommendations.
• Fertilizers are generally placed in a circular band beneath the canopy and incorporated lightly into moist soil.
• Split application and mulching reduce nutrient loss.

Weed and soil management:

• Basin cleaning, slashing, mulching and cover crops are used to suppress weeds.
• On slopes, contour bunds and vegetative barriers reduce erosion.
• Irrigation during flowering and nut development can improve yield in dry regions.

Intercropping:

• During the juvenile period, groundnut, pulses, pineapple, vegetables or medicinal crops may be grown where climate permits.
• Intercrops should not compete severely for water, nutrients or light.
• Deep ploughing near trees and climbing intercrops that interfere with the canopy should be avoided.

Flowering and fruiting:

• Cashew bears terminal panicles containing both male and bisexual flowers.
• Pollination is mainly aided by insects.
• The true fruit is the cashew nut, while the swollen juicy peduncle is the cashew apple.
• Dry, sunny weather during flowering favours pollination and fruit set; rain and high humidity may encourage flower diseases.

Harvesting:

• Mature fruits are generally allowed to fall naturally.
• Fallen fruits are collected frequently to avoid deterioration and pest damage.
• Nuts are detached from the apples by twisting.
• Nuts are sun-dried for several days until their moisture content is safe for storage.
• Dried nuts are stored in clean, dry and ventilated conditions.
• Cashew apples can be used for juice, syrup, fermented beverages, jam and other products.

Integrated pest management:

• Tea mosquito bug: Maintain orchard sanitation, prune overcrowded branches, conserve natural enemies and apply recommended insecticides only at critical stages.
• Cashew stem and root borer: Inspect trunks regularly, remove grubs from galleries, clean affected portions and destroy severely infested trees.
• Leaf miner and flower pests: Monitor populations and avoid unnecessary broad-spectrum sprays.
• Collect and destroy infested plant material.
• Maintain balanced nutrition and an open canopy to improve tree vigour and spray penetration.
• Follow local threshold-based recommendations and rotate insecticide modes of action.

Processing sequence:

1. Cleaning and grading: Raw nuts are cleaned and separated according to size for uniform processing.
2. Conditioning: Nuts are treated by steaming or controlled roasting to make the shell brittle and facilitate shelling.
3. Shelling: The shell is cut or cracked carefully to release the kernel without excessive breakage.
4. Kernel drying: Shelled kernels are dried to loosen the thin testa.
5. Peeling: The testa is removed manually or mechanically.
6. Grading: Kernels are graded as wholes, splits, butts, pieces and scorched grades according to size, colour and integrity.
7. Quality control: Damaged, rancid, insect-infested or discoloured kernels are removed.
8. Packing: Kernels are packed in moisture- and oxygen-resistant containers, often under vacuum or inert gas, to prevent rancidity.

Safety precautions:

• The shell contains cashew nut shell liquid, which is rich in caustic phenolic compounds.
• Direct skin and eye contact can cause severe irritation or burns.
• Workers should use gloves, protective clothing, eye protection and suitable tools.
• Processing units require good ventilation, safe heat control and proper management of shell liquid and waste.

Quality considerations:

• Uniform conditioning improves shelling efficiency.
• Excessive heat causes scorching, while inadequate treatment increases kernel breakage.
• Kernels must be protected from moisture, insects, oxygen and strong odours.
• Hygienic handling is essential because the product is consumed directly after roasting or further processing.

Climate:

• Rubber requires a warm, humid, equatorial or tropical climate.
• An optimum temperature of about – is favourable.
• Annual rainfall of approximately –, distributed over most of the year, supports good growth.
• High humidity and abundant sunshine are beneficial.
• Strong winds may cause branch or trunk breakage, while frost and prolonged drought reduce growth and latex yield.

Soil:

• Deep, well-drained loam or lateritic soil with good moisture-holding capacity is suitable.
• The soil should be at least about deep and free from a shallow hardpan.
• Rubber tolerates acidic soils, commonly within a pH range of approximately –.
• Waterlogged, saline, alkaline and shallow rocky soils are unsuitable.

Propagation by budding:

1. Seeds from vigorous trees are germinated and seedlings are raised as rootstocks.
2. Budwood is collected from selected high-yielding clones maintained in budwood nurseries.
3. A healthy bud patch is removed from the bud stick.
4. A matching window is opened on the rootstock bark, and the bud patch is inserted and tied firmly.
5. After successful union, the wrapping is removed and the rootstock stem is cut back to encourage bud growth.
6. The resulting material may be planted as a budded stump, polybag plant or advanced planting material.

Budding combines a vigorous seedling root system with the uniform yield and quality of an elite clone.

Land preparation and planting:

• The land is cleared selectively, and roads, paths and drainage channels are planned.
• On sloping land, contour lining, terraces, silt pits and vegetative barriers are used to reduce erosion.
• Windbreaks are established in wind-prone regions.
• Pits are prepared and filled with fertile topsoil and organic matter where recommended.
• Budded plants are set out at suitable spacing, often in the range of about – trees per hectare, depending on the system.
• Planting is done at the beginning of the rainy season, and the bud union is kept above soil level.

Immature-phase management:

• Dead plants are replaced quickly to maintain a uniform stand.
• Rootstock shoots and unwanted side branches are removed.
• Controlled pruning develops a straight trunk and a balanced crown without injuring the main stem.
• Leguminous cover crops suppress weeds, add organic matter and reduce soil erosion.
• Weeds around young trees are controlled by ring weeding, slashing, mulching or careful herbicide application.
• Fertilizers are applied in split doses according to age, soil and leaf analysis.
• Mulching and drought protection improve survival.
• Regular monitoring is required for root diseases, abnormal leaf fall, powdery mildew, termites and bark damage.

The main objective is to obtain rapid, uniform girth increment so that trees reach tappable size as early as possible.

Principle of tapping:

• Latex occurs in laticifer vessels present in the bark.
• Tapping removes a thin shaving of bark to cut these vessels without injuring the cambium.
• Trees are opened for tapping only after they attain the prescribed girth and sufficient bark thickness.
• A controlled slope allows latex to flow along the cut into a collection cup.

Tapping notation:

• denotes a half-spiral tapping cut.
• denotes a full-spiral cut.
• means tapping once in two days, while means once in three days.
• Thus, indicates a half-spiral cut tapped on alternate days.

Good tapping practices:

• Maintain the recommended depth, slope and bark-consumption rate.
• Avoid cambium injury, deep cuts and excessive bark removal.
• Collect latex promptly and keep cups, spouts and tools clean.
• Rest or modify tapping during severe drought, leaf fall or tapping-panel dryness.
• Shift panels according to the recommended schedule so that bark can renew.

Yield stimulation:

• Ethephon may be applied to the tapping panel in selected systems to release ethylene and prolong latex flow.
• Stimulation must be matched with clone, tree health, tapping frequency and regional recommendations.
• Excessive stimulation or over-tapping can cause bark damage, reduced tree vigour and tapping-panel dryness.

Sustainable tapping aims to maximize long-term yield rather than obtain excessive short-term latex flow.

Latex collection and preservation:

• Latex is collected in clean cups after tapping and strained to remove bark, leaves and dirt.
• Field latex must be processed promptly because microorganisms cause premature coagulation.
• When temporary preservation is necessary, an approved preservative such as ammonia is used at the recommended concentration.
• Field coagulum, cup lumps and tree lace are collected separately from clean latex.

Production of ribbed smoked sheets:

1. Clean latex is standardized or diluted to the required consistency.
2. A measured quantity of dilute formic acid or another approved coagulant is mixed uniformly.
3. Latex is poured into clean coagulating tanks or trays and allowed to set.
4. The coagulum is cut and passed through smooth rollers to remove serum and reduce thickness.
5. It is then passed through a grooved roller to produce the ribbed pattern.
6. Sheets are washed and hung to drain.
7. They are smoked and dried under controlled temperature and ventilation.
8. Dried sheets are visually graded for colour, cleanliness, bubbles, mould and other defects before packing.

Crepe rubber:

• Fresh coagulum or selected field coagulum is repeatedly washed and passed through a series of creping rollers.
• Rolling produces thin, crinkled sheets with a large surface area.
• The crepes are air-dried or dried under controlled conditions rather than heavily smoked.
• Pale latex crepe is produced from clean, high-quality latex, whereas lower grades may use field coagulum.

Quality control:

• Clean equipment, correct acid concentration, uniform rolling and controlled drying are essential.
• Excess acid, contamination, overheating and incomplete drying lower elasticity, colour and storage quality.