Plucking

Plucking in tea is synonymous with harvesting in other crops. The tender apical portions of shoots consisting of 2-3 leaves and the terminal buds are nipped off in plucking. The plucked shoots are manufactured to produce tea.

Removal of the apical portion of a tea shoot stimulates growth of the dormant leaf and buds below the apex. The stimulated buds become active and start laying down initials of cataphylls, known as janams in North East India, of normal leaves and of another appendage intermediate between janam and leaf, which is known as fish leaf. While laying new initials, the bud swells up and after reaching a critical stage, starts unfolding janams, fish leaf and normal leaves in succession. All these appendages carry axil buds, which are capable of producing normal shoots of equal vigour. Advantage has been taken of this unique property in designing plucking system.

Plucking systems

Three plucking systems are presently in vogue. They are:

  • Janam plucking
  • Fish leaf plucking
  • Single leaf plucking

In theory, only janam should be left behind on the stubs of plucked shoots when following the janam plucking system, but in practice some fish leaves are also left on the bushes along with janams. This cannot be avoided for the sake of maintaining a flat plucking surface. Similarly, fish leaf plucking and single leaf plucking systems are generally a mixture of the two, with predominance of one or the other.

Whatever may be the plucking system, the harvested leaf should not be coarse as coarse leaf is harmful for quality of the product. Secondly, shoots below the plucking surface should be left alone.

Janam plucking is the system followed in North East India since under its soil environmental condition; the system has proved superior to the other systems. Other countries claim superiority of one or the other two remaining systems under their cultural conditions.

Due to janam plucking, the major bulk of tea produced in North East India is derived from the tiny janam axil buds.

Shoot production

Light pruning stimulates the dormant buds on the short 2.5-3 cm pieces of stems known as sticks, to produce a new set of leafy branches, called primaries. When the primaries grow to a pre-set height above the bush frame, these are tipped (broken back) parallel to the ground surface. The average height of the fish leaf on the primaries is the usual height of tipping in N.E. India. All leaves left on the bushes below the tipping level are known as maintenance foliage. Tipping stimulates the buds on the axils of the leaves borne by the primaries, but the stimulus becomes weaker at increasing distance from the point of tipping. As a result, the top most point axil buds of all tipped primaries produce lateral shoots, which declines to 50% in the case of the second axil buds and 25% in the third.

The lateral shoots are plucked when they produce two or more leaves above the tipping level. Plucking of these lateral shoots of the first order originating from the axil buds on the primaries stimulates the growth of the second order laterals which when plucked produce the third order laterals and thus the production of successive orders of laterals continue until the end of the plucking season. In N.E. India up to 8th order laterals have been produced in a year.

Maintenance foliage

Photosynthetic capacity develops gradually in a young, expanding tea leaf and it does not attain full capacity before attaining more than half its final size. It therefore, follows that the young shoots harvested for the manufacture of tea grow largely at the expense of the metabolites supplied by the mature maintenance foliage remaining below the plucking table. Hence adequacy of maintenance leaves must be assured to ensure sustained productivity of tea bushes. Under conditions of North East India, it has been observed that on an average five maintenance leaves per primary satisfy the requirements for health and productivity of tea.

Maintenance leaves on a tipped and plucked primary can remain for a maximum of 18 months, although its efficiency as a photosynthesising organ goes on diminishing after about 6 months. However, a very old maintenance leaf does not draw materials from other maintenance leaves. The leaf drops if it cannot generate enough materials to meet its own need.

Standard of plucking

Standard of plucking denotes the type of shoot harvested. Depending on the length of plucking round, or the type of shoots harvested, there may be five standards of plucking as follows:

Plucking standard

Name of the System Shoot size
Breaking back
Plucking Round
(days)
% crop gained/loss
over standard plucking
Fine 1 + B; small 2 + B
Done
5/6
– 11.3
Standard Large 1 + B; all 2 + B

small 3 + B & single banjis

Done
7
Base
Medium All 2 + B; 3 + B;
single & double banjis
Not done
7/8
+ 0.5
Coarse 3 + B or larger shoots
all banjis
Not done
8 or more
+ 28.2 to 38.4
Black All 1 + B; 2 + B &

single banjis

Done
6/7
– 5.0
   

To maintain a balance between quality and yield, 75% fine and 25% coarse leaf in the harvest is ideal.

Plucking rounds

The time interval between two successive plucking is called plucking round. Plucking round may be extended from 4 to 14 days, but to keep a balance between crop and quality, normally 6-8 days plucking round is practised in North East India depending on the growth rate as well as quality of tea one desires to produce. The time required for unfolding of successive leaves from a growing bud vary from 3 to 6 days depending on climatic variation. This is called leaf period. The mean leaf period of seed jat plants of N.E. India is 4 days during the main flushing season and the leaf should be plucked a day earlier than twice of the leaf period (2 x leaf period – 1 = 7 days). The type of shoots left out during previous plucking round determines the size of harvestable shoots in the next round, as is evident from table below:

Type of shoots available on different plucking round

Type of shoot

left in the bush
Type of shoots harvested
after
4 days
8 days
12 days
Only bud
1 + B
2 + B
3 + B
1 + B
2 + B
3 + B
4 + B*
2 + B
3 + B
4 + B*
5 + B*
       

* After 4+B or 5+B shoots go banji

Creep and breaking back

It is advised to pluck close to janam and not allow undue rise (creep) of the plucking table, since the latter results in crop loss. Under normal conditions, the creep should not exceed the following limits:

Type of Prune
By end July
By end August
By end November
LP
2.5 cm
3.5 cm
5 – 6 cm
DS
2.5 cm
3 cm
4.5 – 5 cm
MS
2.5 cm
3 cm
4 cm
UP
2.5 cm
3 cm
4 cm
       

Under a good plucking system, breaking back is not required. However, this becomes necessary when rounds are very long and supervision is improper as otherwise it results in crop loss.

Banji shoots:

Leaving banji shoots on the surface until they come through results in loss of crop, which could be as high as 90 kg/ha. This loss is attributed to :

  • Uneven surface resulting in inefficient plucking
  • Rare production of laterals in such shoots
  • Hindrance in the metabolic activity of the whole bush