Rejuvenation pruning and replanting in tea

ABOUT 50 per cent of our tea bushes are more than 50-years- old. Despite this, productivity of tea in south India is very high as compared to many other tea growing countries. Therefore, under south Indian conditions it is rather difficult to stipulate the economic longevity of the tea bush. Certain sections of tea in south India had been planted with intrinsically low yielding China jat. With rising cost of production, it is not economical to maintain these areas. Such areas with low yielding China jat need to be replanted with high yielding planting material. Such areas with low yielding China jat. With rising cost of production, it is not economical to maintain these areas. Such areas with low yielding China jat need to be replanted with high yielding planting material.

In a stand of seeding tea where the population is extremely heterogeneous, vacancies had been created due to death of plants that could not withstand unfavourable weather and indifferent soil conditions or due to the occurrence of root diseases. Infilling of vacancies with good planting material and consolidating the stand of tea will no doubt be helpful in enhancing the productivity of the fields. Nevertheless, when the vacancy increases above 40 per cent, it would be rather pragmatic to consider replanting in such fields.

The practice of pruning during the hot dry weather in the yester years resulted in severe sun-scald injuries and subsequently the occurrence of canker and wood rot. Bushes inflicted with these diseases do not respond fully to the agro inputs or to improved cultural practices. Rejuvenation pruning of such moribund bushes had been found to be extremely rewarding.

In a rejuvenated field, the told plant population will depend on the extent of vacancy. The total plant population after plural infilling will be about 9000 plants per hectare. By undertaking interplanting along with rejuvenation pruning the population can be increased to 13000 plants per hectare which is comparable to that of replanting in a double hedge system of planting at a spacing of 135 x 75 x 75 cm.

Even with rejuvenation pruning and infilling, the lower level of bush population may not adversely affect the yield significantly as tea buhes have the ability to cover horizontally to a certain point and therefore so long as he tea cover is satisfactory the expected productivity levels could be achieved. Rejuvenation pruning in conjunction with infilling results in significant increase in productivity ranging from 20 to 40 per cent.

Generally, the yield achieved in the previous cycles is surpassed in the rejuvenation cycle itself. The overall increase in terms of quantum of crop depends on the inherent yield potential of the fields. For instance, if a field with a yield level of 2,600 kg per hectare is subjected to rejuvenation pruning, the yield could be increased to 4,000 kg per hectare by the beginning of third cycle.

In the case of replanting, the yield increase will be gradual. Till the end of first cycle after formative pruning, the yield level of replanted field may be marginally higher than that of a rejuvenated field, but pruning; the yield levels could be considerably higher in the following pruning cycles.

This, however depends on the agroclimatic conditions, type of planting material used and soil conditions. Rejuvenation pruning results in considerable crop loss during the first two years as compared to a normal cut across pruning. Similarly, replanting too entails loss in production during the first cycle after planting. Both these programmes can be undertaken only in a phased manner. Case studies on the impact of rejuvenation pruning and replanting had been carried out and for calculation purpose it was presumed that the whole area in an estate is rejuvenated/ replanted in a phased manner. When rejuvenation pruning is carried out in a medium yielding field, there will be a negative impact on the overall production till the sixth year.

In the case of replanting, the negative impact will continue up to the twelfth year. The maximum loss in crop is 5.8 per cent when 10 per cent of the area is under rejuvenation whereas the reduction in crop is likely to go up to about 24 per cent when 10 per cent of the estate is under replanting programme. At the end of 20 years the crop gain will be 31.2 and 48.9 per cent, respectively for rejuvenation and replanting.

Rejuvenation pruning is a costly operation; along with infilling it is likely to cost about Rs. 78,000/- per hectare. If interplanting is also undertaken the cost is likely to go up to Rs. 1,35,000/- per hectare. The above cost also includes fringe benefits to workers. Replanting is an expensive measuring costing around Rs. 2,66,000/- till the completion of one year from planting. If an estate with 400 hectares of area undertakes 10 per cent rejuvenation pruning or replanting each year, the net investment annually in the initial year will be around 34 lakhs for rejuvenation pruning and about 99 lakhs for replanting.

The break even point for rejuvenation pruning and infilling with and without considering crop loss is two years. In the case of replanting, with a margin of ten to fifteen rupees per kg of made tea, the payback period with crop loss is about 15 years and without crop loss is about 7 years. If loan facilities are availed from Tea Board for replanting with an interest rate of 15 per cent for prompt repayment, the payback period will extend by another three to four years.

The abov trend is applicable when replanting is carried out in a medium yielding field planted with Assam jat. If replanting is carried out in a China field the payback period with crop loss will be 12 years. However, in the prevailing price situation, the growers will have to rework the payback period!

Rejuvenation pruning and replanting are labour intensive operations. It is extremely necessary to complete the operations in time for achieving the desired results. The total requirement of workers is almost three fold for replanting as compared to rejuvenation pruning.

Logically it would be ideal to replant the old tea areas over a period of 10 to 20 years i.e., the pace of replanting has to be five to ten per cent. In such a scenario one has to consider the negative impact on total production of the estate, the huge investment cost, the prolonged payback and the enormous labour requirement. With ever increasing cost of labour and inputs and dwindling tea prices it would be the endeavour of every estate to contain the cost of production by at least maintaining the present level to production.

Consequently, estates may be hesistant to incur significant crop loss although it is limited to the initial phase. With uncertain market situation, mobilising huge amount of resources will be a difficult venture for the estates. The prolonged payback period is another criterion that goes against large scale replanting. In a situation, where adequate workers are not available for carrying out even the routine cultural operations, it will be a difficult preposition to muster move workers for replanting.

Rejuvenation, as the name implies is restoration of youthful vigour. It is a medium term developmental measure, with modest levels of investment. It helps in arresting the deterioration of health of bushes, thereby extending their life and aims at improving the yielding capacity of the existing plant population. The low high of pruning can be advantageously utilised for consolidating the stand of tea.

Rejuvenation cannot be construed as a substitue for replanting; it is only a corollary to replanting. Considering the various pros and cons of rejuvenation pruning and replanting, it will only be pragmatic to undertake rejuvenation pruning and replanting side by side. The percentage of area that can be brought under these programmes has to be decided on the basis of the aforesaid factors. Replanting should receive priority over rejuvenation pruning in China fields, areas with more than 40 per cent vacancy and fields where more than 50 per cent of the bushes are affected by deep bole canker, because rejuvenation pruning will not give the expected results in such fields.

Rejuvenation pruning should be undertaken only in fields that have bushes with structural limitations caused by the incidence of wood rot and canker. Replanting in a minimum of two per cent of the total area and rejuvenation pruning in five per cent of the total area, annually, will be helpful in achieving the expected vertical growth in productivity.

J.B.Hudson & D.Durairaj

UPASI TRF, Coonoor

N.Muraleedharan

UPASI TRF, Valparai

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