Plantation Crops : Tea
The oldest known beverage, tea is native of China in South East Asia. It was known to the Chinese as early
as 2737BC, but attained the status of a popular drink in England in 1664 AD. India is the
largest producer, consumer and exporter in tea industry.
Tea belongs to the
genus Camellia and family Camelliaceae.
The original species, which produces tea,
were C.assamica (Assam jats), C.sinensis (China jats) and their natural
hybrid, C.assamica subspecies lasiocalyx (Indo China or cambod type). Being a
highly cross pollinated crop, the present day seedling populations are mixture of both the
above two species, however, from their major share of characters Assam or China
type can be distinguished by the following characters.
|It is a tree
abundant and whippy
to medium green
yield and medium quality
yield but good quality
to drought and frost
tea is an evergreen shrub or tree, leaves are simple, alternate, serrate, flowere
bisexual, with superior ovary, fruit is a capsule.
Clonal selection from
seedling population was taken up by UPASI, Tea Scientific Department, Cinchona and also by
other Tea Research Institutes. UPASI has so far released 27 clones. Certain outstanding
clones released by other Institutes are also used in South India.
average yielding clone, suitable for all elevations, tolerant to drought and wind.
high yielding and quality clone.
well at mid and higher elevations.
yielding, suitable for all elevations.
yielding, fairly tolerant to drought, Can withstand slightly high pH.
clone, resistant to drought and wind; suitable for high elevation.
clone, suitable for higher elevations.
high yielding clone.
Climate and soil
Tea is exacting in its
climatic requirements. The temperature may vary from 16 to 320C and annual rainfall should
be 125 to 150 cm, which is well distributed over 8-9 months in a year. The atmospheric
humidity should be always around 80% during most of the time. Very dry atmosphere is not
congenial for tea. It is grown in plains in North Eastern States but in South India, it is
grown in hill ranges from 600 to 2200 m above M.S.L.
Tea is a calcifuge
crop requiring comparatively low amounts of calcium but high quantities of potassium and
silicon. They can be grown in lateritic, alluvial and peaty soils. Optimum pH range is 4.5
to 5.0 and soil depth should be 1.0 to 1.5m.
Tea can be propagated
by seed and by cuttings. Seeds collected from the fruits of seed baries are soaked in
water and only heavy seeds, which sink, are alone used for sowing in beds. Germination
occurs in 20 to 30 days. At that stage they are carefully lifted and transplanted in
polythene sleeves. They will be ready for planting in 9 months.
The site for the nursery can be selected in a flat land or gentle slope, near
to a perennial water source and easily accessible by road. It should have a good drainage
and should be protected from wind, frost and wild animals etc. approximately, 0.15 ha
nursery area is required to produce 1.25 lakhs cuttings. Nursery area is to be provided
with overhead shade by erecting concrete or stone pillars at a spacing of 3x3m and spread
with 6mm2 mesh double strand coirmat which provides about 67% shade.
The cuttings for
rooting are collected from mother bushes, which are well maintained near the nursery area.
Such mother bushes are pruned well in advance to induce juvenile shoots. These juvenile
shoots are collected in the morning hours and 3cm long cutting each with a healthy mother
leaf and an active axillary bud is prepared. Cuttings from top tender and bottom brown
wood should be avoided. These cuttings are planted in polythene bags (30cmx10cmx150
gauge), filled with growing medium (Jungle soil: river sand 3:1) in the bottom and rooting
medium (Red/subsoil:sand 1:1) in the top 8-10cm. The soil used for rooting media should
have an optimum pH range of 4.8 to 5.0, if high, i.e., 5.1 to 5.5, or 5.6 to 6.0, it must
be drenched with 1 or 2% aluminum sulphate solution respectively @ 1 litre per cubic foot
of soil. This treatment should follow with drenching of twice the volume of plain water to
wash excess aluminum sulphate. The cuttings are carefully planted at the centre of the
bags in such a way that the petiole should not touch the soil and then they are watered.
These bags are then covered with polythene sheets over the G.I. wire arhes and the sides
are tugged well to preserve moisture content. Callusing starts in 4-6 weeks and rooting
occurs in 10 to 12 weeks. When 80% of the cuttings have rooted, the tents are opened in
stages and the overhead shade is gradually reduced to harden the plants.
The land is cleared of
the roots of the fallen trees and drains are taken at suitable intervals depending upon
the slope to conserve the soil. In the olden days, up and down system of planting at
1.2x1.2m are followed. Presently, contour planting either in a single hedge or double
hedge system is followed.
planting single hedge.
planting double hedge.
0.75 x 0.75m
last method has many advantages over the first two viz., early and high yield, better soil
conservation, less weed growth in the hedge and efficient cultural practices. Planting
season normally coincides with June/July and September/October for SouthWest monsoon and
North East monsoon areas. Pits of 30x30x45cm size are dug and plants of 12-15 months old
are planted by removing the polythene sleeves. Immediate after planting, plants are staked
to prevent wind damage.
planting, the soil surface around the plants should be mulched, usually cutgrasses of
gautemala are employed for this purpose. About 25 tonnes of grass is required to mulch one
hectare. Care must be taken to keep the mulch materials away from the collar region last
they may cause collar diseases. If there is a dry weather, mud tubes or etah tubes may be
buried 15cm deep near the plant in a slanting position and one litre of water per plant
may be poured or injected at weekly intervals. This subsoil irrigation helps to minimise
the causality besides encourages developing deeper roots.
Tea requires filtered
shade and if it is exposed to direct sun, its growth is affected. Shade is hence essential
and beneficial to tea as
The desirable characters of a good shade tree like
- It regulates the temperature.
- It minimises the effects of drought and
- It increases the soil fertility
- It helps in recycling of nutrients.
- It helps in getting even distribution
- It serves as windbreak.
- It reduces the incidences of pests.
- It generates additional income by way
of timber and fuel.
- It must be an evergreen tree, easy to
propagate having quick growing and deep rooted characters.
- It provides filtered shade and
withstands frequent lopping.
- It tolerates wind and frost.
- It does not have allopathic effect.
- It has commercial timber value also.
Weeds will be a
problem in young and pruned fields. Manual weeding is never recommended in tea lest more
soil erosion and damage to surface roots and collar regions. Therefore, the following
chemical weed control is alone recommended in tea.
|Type of weeds
salt of 2,4-D (Fernoxone)
propionic acid (Dalapon)
Training and Pruning
In the young tea, when
it has established well, centering i.e. removing the growing point leaving 8 to 10 mature
leaves from the bottom, is done to induce secondaries. When the secondaries reach more
than 60 cm, they are tipped at 50-55 cm height by removing 3 to 4 leaves and bud to induce
tertiaries. Therefore, plucking at mother leaf stage is continued for better frame
development. It takes nearly 18 to 20 months from planting to reach regular plucking field
Pruning is done in tea
- to maintain to convenient height for
- to induce more vegetative growth
- to remove dead and de funct wood and
- to remove the knots and interlaced
Pruning is normally
done 4 to 6 years interval depending upon the altitude of the garden, nature of the
materials etc. the bushes marked for pruning should have adequate starch reserves in roots
otherwise the sprouting following pruning should have adequate starch reserves in roots
otherwise the sprouting following pruning will be less. This can be normally tested by the
common Iodine test and if the starch reserve is less, bushes are allowed to rest for 2 to
3 months. The different types of pruning are as follows: -
||Type of pruning
||Pruning height (cm)
30 Assam Jat
is old bushes affected with cankar and wood rot to invigorate the new healthy branches.
Not done regularly.
formative pruning done to a young tea.
pruning whereever frames are healthy.
pruning whereever frames are healthy.
to postpone pruning and to encourage better frame development.
Immediately after the
rejuvenation or hard pruning, the cut ends are smeared with a paste made of copper
oxychloride and linseed oil (1:1). The prunings, consisting of only small twings and
leaves are buried in trenches of 30cm width and 45cm depth taken across the slope in
alternate rows. The pruned bushes are given washing with 10% lime solution using No. IV
nozzle of power sprayers in order to kill the epiphytic growth of moss and lichen so as to
induce early and even bud break. Lime washing also minimises sunscorch to the bush frame.
The buds from the
pruned shoots grow in a steady succession without any cessation of growth. These are known
as a periodic shoots or primary shoots. These primary shoots should be induced to produce
flush shoots, otherwise known as periodic shoots by regular tipping operation. Tipping is
the removal of terminal portion of the shoot and it varies with jats and pruning height as
given below. Tipping height refers to the number of leaves that must be left above the
pruned cut while tipping in material refers to that portion of the terminal shoot, which
must be tipped off.
|Pruning height (cm)
||Tipping height (cm)
||Tipping in material
||Assam/ Assam Hybrid
leaves and a bud
leaves and a bud
leaves and a bud
leaves and a bud
leaves and a bud
leaves and bud
leaves and a bud
Manures and fertilisers
Tea responds to
manuring and it has been estimated that to produce 100kg of made tea, tea plant utilises
on an average 10.2, 3.2 and 5.4kg of Nitrogen, Phosphorus and Potash per ha. Manuring in
tea starts from nursery stage itself. Once they strike roots (after 4 months) 30g of
soluble mixtures (Ammonium phosphate (20:20) 35 parts, potassium sulphate and Magnesium
sulphate each 15 parts and zinc sulphate and Magnesium sulphate each 15 parts and zinc
sulphate 3 parts) is dissolved in 10 litres of water and is applied with rosecan
for about 900 plants. This must be repeated at 15 days intervals.
recommendation for mature tea is based mostly on soil organic matter status and
anticipated yield. For a field with medium organic matter status the following rates of
application is suggested for every 100kg of made tea anticipated:
|Yield level (kg/ha)
||Rate of Nitrogen (for 100 kg. of made tea)
||No. of split applications
Twenty per cent of the
total nitrogen is given in the form of Ammonium sulphate during March/April. Urea is
recommended in May/June and receding monsoon months avoiding very wet and very dry periods
and it will come to 65% of total nitrogen. Fifteen percent of the total nitrogen is
applied in the form of Calcium Ammonium Nitrate during pre-winter (November-December).
and potassium are always applied together. NK ratio of 1:1 is used for plucking fields
while for a pruned field 2:3 NK ratio is recommended. For rejuvenation pruned field 1:2 NK
ratio is suggested. The enhanced rates of potassium application in the pruned year is to
encourage formation of healthy farmers. Muriate of potash is the sources of potassium used
in tea fields. The NK fertilizers are applied by broadcast for mature tea and is broadcast
and dibbled in along the drip circle for young tea. The interval between two successive
applications should be atleast 3-4 weeks.
is applied once in alternate years @ 90kg P2O5/ha for fields
yielding less than 3000kg/ha for fields yielding between 3000 and 4500kg/ha, 60 to 80kg P2O5/ha
is suggested every year. The soils being acidic, rock phosphate could be advantageously
used. The fertilizer should be placed at 15-22cm depth.
the micronutrients, zinc deficiency is often manifested in young shoots characterised by
reduced leaf size, rosetting, chlorosis and formation of more banji shoots. Application of
zinc sulphate @ 6 to 8kg/ha for high yielding fields every year is the general
recommendation. The above quantity can be given in 4 to 5 split applications during has
been found beneficial to combine other micronutirents viz., Manganese sulphate @ 15.5g/10
litres and boric acid @ 5.5g/10 litres of spray volume along with zinc sulphate spray.
Liming: In the hill
soils, due to the leaching of bases by rain and also due to the incessant application of
acid forming fertilizers, the soil pH is often reduced which affects the physical and
chemical properties of soil. Therefore, periodical application of lime is essential
properties of soil. Therefore, periodical application of lime is essential to amend the
soil and maintain optimum pH. Agricultural lime (Calcium carbonate) and dolomitic lime
(Calcium Magnesium carbonate) are generally recommended for tea soils. The rate of
application is based on soil pH, rainfall, fertilizer usage and length of the pruning
cycle. Roughly lime @ 1.5mt/ha for a pH between 4.5 to 4.9, 3.0mt/ha for a pH between 4.0
to 4.4 and 4.0mt/ha for a pH of less than 4.0 is suggested.
The lime is applied by
evenly broadcasting prior to pruning once in a pruning cycle. First manuring following
liming can be had after 6 weeks and a minimum of 15cm rainfall should have been received
during this period.
Harvesting or Plucking
Plucking consists of harvesting 2 to 3 leaves and a bud. It is the most labour intensive operation in a tea
industry and also decides the yield and quality of made tea. Normally, a pluckable shoot
takes 60 to 90 days for harvesting since its sprouting from the axillary buds. When the
shoot is plucked upto mother leaf, it is known as light plucking and if it is plucked
below mother leaf, it is called hard plucking. The plucking interval and plucking standard
in relation to cropping is given below:
cropping or Rush cropping (60% of total crop)
||April June and
cropping or lean cropping (40% of total crop)
It is essential to add one tier of active maintenance foliage to the bush every year. This is done by mother leaf
plucking during January to March. During the rest of the period level plucking can be
plucking, bush height increases every year in the order of 10cm over tipping height in the
first year, 7.5cm, 7.5cm, 5cm and 5cm over the previous year height in the second, third,
fourth and fifth year respectively.
Yield of made tea per
hectare depends upon many factors such as elevation, clonal or seedling jats, management
practices, severity of pruning, processing techniques etc., Generally, in tea industry, a
field which yields upto 2000kg of made tea/ha is considered as low yielding and 2000 to
3000kg as medium yielding and anything above 3000kg as high yielding fields.
Manufacturing of Tea
Basically, there are two types of processing viz.,
- Orthodox method in which the rolling
operation is done in a series of rollers. The rollers have rotary tables with battens,
jacket for loading the leaf and a pressure cup,
- CTC method (cutting, tearing and
curling) which has a CTC machine, consisting of series of a pair of rollers mounted in
such a way they rotate in opposite directions and the clearance between them is so
adjusted to crush and tear the leaves.
Irrespective of the method, manufacturing of tea involves the following steps:
objective of withering is to reduce the moisture content of leaves by spreading them in
troughs which receive artificial air from fan fitted on one end. At the end of withering,
the leaves attain a flaccid condition for which it may take 12 to 18 hours depending upon
the weather condition.
operation is carried on by a series of machines or in a single roller, during which the
cells in the leaves are broken to liberate the sap containing the polyphenol oxidase, an
enzyme, which in the presence of oxygen, oxidises the polyphenols to produce theaflavins
and thearubigens. These are responsible for colouring of the tea and is a 30-40 minutes.
Afterwards, the fine sifted rolled ones are sent for fermentation while the coarse ones
are again sent for rolling.
tea materials are either spread in concrete floors or kept in aluminum trays. In the
presence of high humidity and proper step decides the quality i.e. strength, colour and
briskness of tea. Fermentation requires 1 hour or 2 hours depending upon the environmental
Drying: This step aims
at stopping the fermentation process and slowly removing the moisture content without a
burnt smell but preserving the inherent quality. This is achieved by passing the fermented
tea in thin layers through conveyors into a drier in which the inlet temperature is
maintained around 250 2800F and outlet temperature is a round 150-2000F.
Proper drying takes 30-40 minutes.
grading, the dried tea is removed of the stalky fibres, which affect the quality, by
passing through fibre separate machines. The bulk tea is passed through different sized
meshes which aid in separation into different grades.
golden Orange pekoe (TGOP)
orange pekoe (BOP)
Many pests and diseases are known to infect tea bushes and cause economic losses. The important pests and
diseases, their typical symptoms and control measures are
adult bugs and hairy orange nymphs suck the sap from fresh leaves and tender shoots;
leaves curl up, dry and die; active from January to September.
and destroy bugs during the initial stages; spray 0.1% Malathion or 0.05% Lindane
borer (Xyleborus fornicatus)
make a typical short-hole on the branches and inside gallaries. A serious problem in low
and mid elevation areas
affected branches are pruned off. Heptachlor 20 EC is sprayed @ 8.5 l in 675 lit. of
water/ha on the pruned frames and prunings
spider mite (Oligonychus coffeae)
upper surface of mature leaves
(8 EC) 1 to 1.25lit/ha.
mite (Brevipalpus californicus)
of leaves often leads to defoliation
exhibit smoky grey colour
leaves turn pale and get twisted.
||Dicofol or Ethion @
mite (Polyphagota rosnemus latus)
pluckable shoot, leaves become rough, brittle and corky in under surface.
surface becomes uneven, curly and metty, exhibiting parallel lines of feeding marks on
either side of the midrib
or endosulfon 1lit/ha.
in tea nursery, infested roots develop galls.
heat treatment of soil media upto 60-800C and application of carbofuran 3G @
80g/m3 of medium.
blight (Exobasidium vexans)
tender leaves and stem and develops translucent spot. Cloudy and wet weather favour
oxychloride 350g in 67lit of water with power sprayer for pruned field at 3-4 days
interval. In the plucking Oxychloride + 210g Nickel chloride in 45lit of water/ha at 7
root diseases (Rosellinia arcuata)
roots show black mycelium on the roots, white star shaped mycelium between bark and wood
and Black lead shot like perithecia seen on collar region.
soil may be drenched with Dithane M-45 @ 30g/10 litres.
||Red root disease
roots exhibit blood red mycelium on washing. It spreads fast but slowly kills.
- Take trenches of 1.2m deep and 45 cm
width sorrounding the infected bushes and uproot and burn the bushes in situ.
- Rehabilitate soil with gautemala grass.
- Soil fumigation with methyl bromide
root disease (Fomes noxius)
root wood turns soft and spongy, it spreads slowly but kills quickly.