Tea World

Lesson 29

Supplying nutrients and organic fertilisation management

A high amount of nutrients are lost through the continual plucking of tea leaves. Moreover, the perennial tea plant requires a considerable amount of nutrients in order to develop roots, stem and branches.

Manuring ensures the availability of essential nutrients that deficient in the soil at optimum quantities and to return the nutrients removed by using the manures of organic origin demanded by the tea bushes for a sustainable productivity. Compost, oil cakes and rock phosphate are the main inputs to substitute the removal on nutrients. Nitrogen is also supplied by regular lopping of low and medium shade trees and leguminous trees (Gliricidia sepium, Gliricidia maculate) which can be grown along roadsides and other vacant patches. Bone meal, fish meal and other manures of organic origin can also be used in available from unpolluted environment; wood ash can also be applied.

Organic fertilisation management     

At the start of the conversion, the tea garden needs to be developed consequently and in stages from a monoculture towards a diversified crop system. Alongside the cash crop tea, plants should be cultivated to improve soil fertility, provide a supply of nutrient (especially nitrogen), increase diversity (habitats for benefical insects), supply wood (fuel and building material) and (if practised) to provide feedstuff for on-farm animal husbandry. Main objective is to provide a sufficient supply of organic matter for the tea bushes. Spreading the organic matter over the site should be given preference to the more work-intensive practice of composting.

 Green Manure (mulch):

The foliage from green manure plants, as well as that from the other crops, should remain as mulch material on the site. In the cases of tea gardens where integrated animal husbandry is practised, care should be taken to choose green manure plants that can also be used as fodder crops.

 Returning Pruning material from tea bushes:

As already mentioned, the pruning material from the tea bushes contains a considerable amount of nutrients (especially after deep pruning and/or rejuvenation). These nutrients should not be removed from the tea garden (e.g. as fuel), but should either be re-applied directly as mulch, or via composting.

Composting and animal husbandry:

On many tea gardens, the people living and working there are often supported in their acquiring and maintaining of, e.g., cattle, as they are thereby assisted in an opportunity to supplement their income. Livestock is an integral feature of organic farming for cowdung, sheep, goat, poultry and pig manure.

Soil reaction

Soil pH should be maintained at about 5.0 by application of agricultural lime or dolomite lime once in a pruning cycle and the quantity of liming material should be determined on the basis of soil pH, rainfall and crop yield.

Shade management:

Adequate attention to the maintenance of optimum stand of shade should be given in organic tea cultivation and should be regulated properly by annual lopping.

Weed control: 

Weeds should be controlled manually by hand pulling during dry period and slashing during monsoon; uprooted and slashed weeds may be retained in the field.

Pest and disease management:

Pest and disease control in organic tea cultivation is primarily preventive rather than curative. If insects and diseases occur, non-toxic biological methods are applied. Within a balanced ecological system, the pests and diseases are controlled by the use of resistant clones, balanced nutrient supply, parasites and predators, pheromones, herbal sprays and by appropriate cultural operations. Certain caterpillars like flushworm, leaf rollers and tea tortrix can be controlled to a certain extent by manually removing the infested shoots during plucking. Blister blight disease can be controlled by the use of resistant clones and by modifying the micro-climate by the thinning of shade trees.

Control measures for some pests and diseases:

Blister blight (Exobasidium vexans) and Red root rot ( Poria hypolateritia)

Copper preparations permitted in emergencies (max. 3 kg pure copper per ha); Preventive measures like micro-climate, hygiene precautions etc.are important.

Nematodes (Meloidogyne ssp.)

Tearing out and burning of infested tea bushes should be adopted. The infested tea bushes should be uprooted. As preventive measures, use of plant-bags in the seed bed; use shade tree Indigoferra teismanii as a trap plant can be adopted. Sowing of Tripsacum laxum (Guatemala grass) before starting a new plantation reduces nematode infestation.

Tea mosquito bug( Helopeltis theiovora).

In emergencies, neem extract should be applied. Encouraging useful insects such as ladybirds and introducing Bacillus thuringiensis are some of the preventive measures against helopeltis. In severe cases pruning is the only measure to control Helopeltis. Plucking should always be started in non-infested sections.

Red spider mite (Oligonychus coffeae)

In emergencies, neem extract or tobacco extract can be applied. Adequate  shade suppresses development of red spider mite.The sections should be kept weed free.

Bunch caterpillar (Andrata bipunctata),Looper caterpillar (Biston surpressaria) Red slug caterpillar(Etrusiamagnifica).

The caterpillars should be collected from the ground, tea bushes and shade trees (in all stages of development).The moths should be trapped by light trapping.

Scarlet Mite(Brevipalpus phoenicis)andPurple Mite(Calacarus carinatus)

Growing green manuring plants and shade trees, growth can be suppressed.In emergencies or after pruning lime and soda washing should be done.

 Common Thrips(Taeniothrips setiventris) andAssam-Thrips (Scirtothrips dorsalis)

Growing of green manure plants and shade trees; lime and Soda washing; disturbing the soil around the tea bush stem during the cold months will destroy the pupae.

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