Increasing tea cultivation

Published August 20, 2007

TEA is a sub-tropical evergreen plant, a native of China, where it was first used as a drink. Tea is mostly Asian in origin. India, Bangladesh, China, Sri Lanka, Uganda, Kenya and Indonesia are among the world's largest producers of tea. The shrub is of wide adaptability and grows in a varying range of climates and soils in various countries.

The three basic factors necessary for tea culti vation are annual rainfall above 1000 mm, air temperature 10oC with soil’s pH value ranging from 4.5 to 6.5 and cheap and adequate availability of labour.

Mansehra in the North West Frontier Province has been selected for cultivation of the shrub, where the soil ensures all the basic needs. Commercial pro duction of tea is also possible here. Tea plants after starting production remain productive for well over several de cades.

The plant best thrives under high and uniformly distributed rainfall, with a minimal dry season and a mean annual temperature of 18 to 20oC, within a range of 12 to 30oC. Its best location is tropical hills. It can grow successfully in varied zones, especially in the monsoon climate of the tropics. Production of fine tea is the result of a long and closely controlled period of processing, including fer mentation, to yield the characteristic colour in the tea cup.

However, the growers must carefully organise plucking so that only shoot with leaves at particular stages of growth and development are taken i.e. the newly grown vegetative shoots comprising terminal bud, two to three leaves immediately be low it and the intervening stalk. It is this part of the vegetative growth that contains the highest concentration of tea caffeine and polyphenols, which produce the best quality tea.

Tea leaves contain three distinct chemical i.e. essential oils, alkaloids and polyphenols. Specially the aroma and flavour are imparted by theol, the ethereal oil found in the leaves. The bitterness and astringency is due to the oxida tion products of polyphenols, while theine (tea caffeine), an alkaloid with the same chemical structure as caf feine is responsible for stimulating and refreshing qualities of the capped infusion.

The polyphenols in tea, com monly called tannins, are derivatives of gallic acid and catechin, which are oxidised by the enzyme polyphenol oxidase during fermentation to produce orthoquinones. These oxidation products subsequently polymerise to form theaflavins which are respon sible for the bright colour of the infu sion and thearubigins, which give tea its body and strength. The bud and two youngest leaves on the shoot have the highest concentrations of polyphenols and caffeine and therefore produce the best quality tea.

Thus, terminal buds, appro priately called 'golden tips' and highly prized in the trade, are super rich in polyphenols and high in caffeine, or ange is in the smallest (youngest) leaf (28 per cent polyphenols) and also contain ing many 'golden tips', based on the second leaf (21 per cent polyphenols).

Fluoride in tea strengthens teeth and reduces tooth decay while polyphenols inhibit the growth of harmful micro-organisms and improves oral health. Tea boosts the immune system. It contains very low quantity of sodium and is an ideal beverage for people with high blood pressure. Polyphenols in tea could contribute to a reduction in diabetes. It also acts as an anti-bacterial agent. It increases alertness and decreases drowsiness, fatigue and stress. Originally tea was regarded a medicine and subsequently gained status of a social beverage.

Skilful hand picking of tea ensures that only those parts of the shoot at the right stage of development are harvested. This means that the picker takes the maxi mum amount of good quality leaf which is compatible with the continued health and wellbeing of the bush by ensuring that sufficient leaves are left intact to allow continued normal growth and vigour. In general, this means that picking should be repeated every 7-10 days on lowland estates and every 14 days on tea grown higher up, where cooler temperatures mean that growth rate is slower.

Experience pickers can harvest around 35-kg tea per day with a mature tea bush yielding about one kg of fresh green shoots per year. With wa ter content of up to 80 per cent, these fresh pickings are processed into black tea to give a ratio of 4:1 plucked fresh shoots to processed black tea. Scru pulous hygiene, which is practised throughout the process to prevent con tamination and the acquisition of taints or off flavours, starts at picking and is maintained as the freshly picked shoots arrive at the factory. Here, they are inspected to ensure at least 75 per cent 'good' shoot per basket, no pre-fermentation and a weight loss, through water evaporation after picking, of no more than 0.5 per cent.

Once the inspectors are satisfied with fresh-leaf quality, the leaves begin a 48-hour process involv ing withering, rolling fermentation and drying to achieve the twin aims of care fully controlled water loss through evaporation and the development of flavour through fermentation.

Most suitable land for tea plantation is located in Mansehra's hilly terrain. Some parts of Swat and Azad Kashmir have also been found suitable for produc tion. The social transformation in volving consumption basis offers a premium on efforts to boost produc tion through research on this com modity .. Pakistan spends about $223 million annually on import of tea.

The government had started cultivation of tea plants in Shinkiari, NWFP, in 1980. In 1986, it acquired 50 acres in the area to set up a Tea Research Station, where tea was cultivated on around 35 acres. The Pakistan Tea Re search Institute, Mansehra, has also decided to enhance the area under cultivation to about 3,000 acres to achieve self-sufficiency in the com modity. One local company started tea cultivation project in Mansehra district formally in 1988 and locals started cultivation in their fields in 1999.

Tea cultivation is labour-intensive, creates employment op portunities and helps in the eco nomic development of the region. If the government spends only one per cent of its amount of import on the development of tea, it would give a good start for research and devel opment.

It may be suggested that the prospects of tea cultivation in the country seem to be very bright due to presence of suit able soil and climatic conditions in the Northern Areas of the country, where it is possible to introduce tea cultivation on a garden scale as is being practised in other coun tries. The efforts in local cultivation of tea would hopefully reduce import of tea and save valu able foreign exchange. The crop of fers immense scope for long-term cash return to growers with small land holdings.

In commercial plantations, tea is grown mainly from selected cuttings and is contour-planted, interspersed with shade trees, which also help provide biomass to the soil. In its natural state, to grow to about three meters, but in commercial culture it is pruned down every two or three years to bush height for easy hand picking. Pruning also encourages a continued production of a flush of fresh, tender shoots for plucking, which is done every seven to 10 days, depending on the elevation.

Tea is a natural product, grown and processed in clean and hygienic environments, in a manner acceptable to modern ecological requirement and concerns. It is also a beverage with numerous health properties and benefits. Scientific research indicates that regular tea drinking reduces the risk of heart disease, strokes, and certain forms of cancer, maintains proper body fluid balance, relieves fatigue and strengthens teeth.

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