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Monday, July 18, 2011

Land Selection and Preparation for Tea Cultivation

Land is the most important property in agriculture. If we consider it more further, soil is the priceless property in our agricultural lands. These posts will describe and explain how a land should be selected and prepared for tea cultivation without leaving the land to be eroded and precious soil is washed off with runoff water. Kindly click on the "Land Preparation" button above or follow the links below to read them in detail.

Tuesday, October 19, 2010

Manure or fertilizer for Vegetative Propagated (VP) tea Nursery in Sri Lankan weather and climatic conditions

Fertilizer for tea nursery is not meant for fast and high growth in green foliage. It should be focused on the development of the frame of the young tea plant, since; a sustainable crop could not get from a bush with a poorly developed frame of the plant. The formulation of the tea nursery fertilizer mixtures have been done with that scope in mind. 

Basically there are two tea nursery mixtures used in Sri Lanka, namely T65 (MAP) (P-source is mono-ammonium phosphate) and T65 (DAP) (P-source is di-ammonium phosphate).  Apart from the market availability, it doesn’t matter to use MAP or DAP for the mixture. But, T65 (MAP) dissolves fast, so that, it is easier to handle. 

Composition of T65 (MAP) Mixture
Parts by weight
Chemical name of the ingredient
Nutrient content
Sulphate of Ammonia
20.6% of N
Mono-Ammonium Phosphate (MAP)
20% of N and 35% of P2O5
Sulphate of Potash
48% of K2O
Epsom Salt
16% of MgO
65 (Total Parts)

T65 (MAP) mixture contains 10.9% N, 10.8% P2O5, 11.1% K2O and 3.7% MgO

Composition of T65 (DAP) Mixture
Parts by weight
Chemical name of the ingredient
Nutrient content
Sulphate of Ammonia
20.6% of N
Di-Ammonium Phosphate (DAP)
18% of N and 46% of P2O5
Sulphate of Potash
48% of K2O
Epsom Salt
16% of MgO
65 (Total Parts)

T65 (DAP) mixture contains 10.5% N, 10.6% P2O5, 11.1% K2O and 3.7% MgO

There is no need to use exactly the same mixtures mentioned above, to a tea nursery, but be sure the nutrient content and composition is approximately the same, as indicated.

How to apply the nursery fertilizer mixture to a VP tea nursery (in polythene bags) 

Tea nursery fertilizer mixture is a foliage application with watering cans. If you use T65 (DAP), it should be ground well and make a paste, before dissolving it in water, since DAP is poorly dissolve in water.
It is not advisable to apply fertilizer to the young plant, or planted shoot cuttings, before the roots are emerged. Therefore, the time of the first application of fertilizer is, after 2-3 months of planting.  

Dissolve 35 g of above mixture in 5L of water and apply it onto, approximately 1 m2 of the tea nursery, in fortnightly intervals. Generally, with 4 inch diameter polythene bags, 1 m2 contains 120 nursery plants.

In about 5-6 months after planting of shoot cuttings in nursery bags, increase the weight of fertilizer up to 70 g/5L water/m-2 of nursery area. 

Note that, it is compulsory to wash off the fertilizer mixture from foliage with clean water within 15-30 min time, to avoid scorching the leaves due to high concentration of fertilizer. 

Application of Zinc Sulphate (ZnSO4) to induce bud break in tea nurseries

Branching is important in tea bush because, the higher the number of branches, higher would be the number of shoots harvested. Also, branching must be induced from the lower parts of the main stem of the bush, so that, they would not be cut off in seasonal pruning of branches. Therefore, induce of branching from the base of the main stem is commenced from the nursery stage. 

Foliar application of ZnSO4 is done to induce bud break at the nursery stage. One week after each application of T65, 14 g of ZnSO4 is dissolved in 4.5L of water and spray this with a Knapsack (hand) sprayer to approximately 4500 (38 m2) nursery plants. Repeat the application at 4-6 week intervals up to 4 applications per year.

Click her to view fertilizer for Seedling Tea Nursery 
 Well grown Tea (VP) Nursery Plants

Wednesday, September 29, 2010

Drought Management or Drought Mitigation - in tea cultivation

Drought management is not applied only in a drought but it should be integrated practices from land selection to harvesting of mature teas. Therefore, this tropic is divided into several sub-tropics and discussed separately, by each step.

Selection of land for tea cultivation

The land should be less than 70% of slope, and preferably more than 60-100 cm in depth. Gravel portion of the soil is better to be less than 10% while avoiding hard-pans containing gravel or other hard material. Also care should be paid on the type of soil, although it has no connection with the drought mitigation. Tea is well grown in Red Yellow soils with a good top soil rich with organic matter. 

Land preparation

Land preparation and minimize erosion during that will result in a healthy root system, which helps tea bush to survive in a drought. Always take care to minimize soil erosion in land preparation. Organic matter content in the soil is also a factor affecting water content in the soil. Avoiding heavy rain seasons, preparing the land from the top of the slope in small blocks, avoiding leveling land to a very fine texture, prepare lateral drains alone the couture lines, rehabilitation of the land with grass at least to 18 month time, planting alone the couture, etc. are some of the practices that matters with drought mitigation of tea.

Planting of young tea

A vigorous tea plant will always be face the drought better than a week one. Therefore, selecting a healthy nursery plant is very important. Ground propagated tea nursery plants will have damaged roots when pull out for field establishment. Select a good bag-planted tea plant for planting. Well branched tea plant with a healthy root system makes the tea plant recover and establish in the field, early. The nursery bag should be at least 6 inch in depth and 4 inch in diameter. Never cultivate plants from ground nurseries. Always go for bag planted nursery plants.

Planting is done in couture lines with spacing of 2 feet withing the row and 4 feet between two rows. Use a thatching between tea rows after planting. 

Management of tea bush

Stop harvesting in severe and prolonged droughts. When the drought is not so severe, fine harvesting method must be adopted (harvest only the bud and two leaves, leaving a leaf to the plucking table - so called as mother leaf plucking).

Always avoid pruning tea bush into drought seasons. Pruning must be done with the onset of a rainy season. Also, care must be taken to leave 2 - 3 healthy branches un-pruned in the bush to facilitate adequate photosynthesis and detoxification of toxics synthesized during root death due to branch pruning. Never harvest shoots in remained branches (lungs). Bury pruning branches in every other tea inter-row space. This will increase the organic matter content in soil increasing the water holding capacity. In the same time rain water will better absorbed into soil due to decreasing in the speed of runoff water. 

Avoid manure application. This may harmful in drought since the moisture in the soil sap is inadequate, and thus causing nutrient concentration in the soil sap more concentrated than tolerable to the tea roots.

Weeds compete with tea plant for moisture. Therefore remove weeds the tea land at the early state of the drought and preferably apply a thatching or mulch. Hand pulling and scraping weeds will loose the top soil layer causing more moisture evaporated from the soil. If the drought is prolonged and weeds are still there, slash weeds with a knife without pulling or scraping. Chemical weeding may be practiced in such a situation without affecting much to soil moisture.

When tea plant continuously producing shoots, and harvested, it adds an additional stress to the plant. Therefore, skiffing (removal of 2 – 3 inch top layer from plucking table) can be practiced, in prolonged drought conditions, so that, the production of shoots is temporarily reduced. This will reduce the annual yield but, in return, bushes will not die. 

Chemical Applications in Drought Management

Water is removed through transpiration form the tea leaves. If we can reduce the transpiration, that will help the tea bush to withstand the drought conditions. Spray kaolin or Kieserite to the foliage. Kaolin will cover the tea leaves as a thin layer on the leaves while Kieserite will close the stomata reducing transpiration. Care must me applied, when applying Kieserite to foliage, so that the solution would not too concentrated (less than 5%), sucking out the water in the leaves. 

Wednesday, April 29, 2009

Field establishment of young tea

Tea is well grown in Reddish Brown soils in 4.5-5.5 pH range. Depth of the soil layer 1m is optimum where less than 60 cm is considered unsuitable for tea cultivation. Tea is cultivated alone the contour lines where the slope of the land is not exceeding 70% (45 degrees = 100%). The spacing between two rows is 1.2 m & within row is 0.6 m.

Planting holes are digged to a depth of 18" and diameter is 12". Fill the planting holes 3/4 way with top soil, removed with gravel & leave about 1 week to settle before planting the young plant. This prevents the collor region of the stem covered with soil, when it settles, and possible fungal infections.

Remove the polythene bag from the young plant and plant it in the partially filled planting hole. Fill the rest of the gap with soil. Supply some backing with 2 sticks to prevent movement with wind, and a mulch to prevent siol erotion. (keep mulch 4"-6" away from stem to avoid fungal infections and scratches to the bark)

(this article is made very brief, if someone is interested pls leave a comment/question in the archive to get further help)

Planting & Management of Seedling tea Nursery

Seedling plantign is now not widely done since Vegetatively Propergated (VP) plants give higher yields and uniform growth. (This article is written on a request by a reader)

Harvesting of seeds

Mature tea fruits are dark greed to light brown in color depending on cultivar. When the ourter coating of the fruit is removed, seed(s) must be dark brown seed coat. Light brown and yellowish ones are not mature enough to propergate. Picking fruits before they are fallen is a must as viability of seeds become low when they fall on the ground. If you collect seeds after falling them on ground, it should done daily to avoid collecting old fallen seeds, also ground must be free of weeds.

Tea seeds don't have any dormant period, once picking from the tree they can be put in a nursery. Never take seeds picked more than 7 days before, as viability decreases rapidly.

Nursery management

Presoaking seeds 2-3 days in water, could be done prior to put in the nursery to decrease the time taken for crackin the seed coat. This is not necessary practice. However, put seeds in water for float-sinker assessment. Seeds that are sinking can be taken for germination.

Coarse river sand removed only with larger particles is suitable as a nursery media. Depth of the nursery is 4"-6" with any convenient width and length. 1" sand layer is removed from the nursery and seeds are sown after which they are covered with the sand layer removed before. Seeds must be sown at 0.5"-1" depth. Placing piece of coir matting will protect seeds from bird's damages. Water twise a day.

Transfer plants from nursery to bags.

Germination commences about 2 weeks after sowing and reaches maximum at the 3rd-4th week. Once the tip of the root emergs from the seed coat, they should transfer to nursery bags filled with soil medium. Care should be taken not to damage the root end emerging (tap root).

Fertilizer application

After 2 weeks of planting fertilizer application can be done. Pls refet to my blog archive on Fertilizer for Tea Nursery for the details. (Fertilizer for seedling & VP has no much difference in nursery management) Shading is not necessary as this is a natural process.

Planting in the field

After 8-10 months in nursery bags, depending on growth, plants are ready to plant in field. Care should be taken not to allow the tap root to reach or penetrage in to nursery soil coming out from the bag. This will sure damage the tap root when transplanting.

Please refer to my archive on Field establishment of young tea for further details.

Friday, April 24, 2009

Fertilizer for Seedling Tea Nursery

Fertilizer applicatoin for tea nursery is an important matter for a vigorous and healthy young tea plant for planting. The nursery mixture of fertilizer is suitable to having N%, P% & K% 10%, 11% & 4% respectively, since it has been found that a tea plant in that stage requires nutrients in such composition.

Approximately 25-35 g of the mixture desolved in 5L of water is adequate for approximately 100 nursery plants as a folier application. The rate could be made double with the age and growth of young plants. ZnSo4 can also be applied to foliage for inducing bud break, at the rate of 5g in 5L of water for 5000 plants.

Soil pH and nutrient testing in soil

Site specific fertilizer application is the newest method of manuaring. This method need to have checked the soil pH and nutrient levels in a lab. Chemical testing for nutrient is essencial if site specific fertilizer applications are to be done.

It is necessary to maintain soil pH in 4.5 to 5.5 range to make soil nutrients available or soluble for tea plant.

Thursday, April 23, 2009

Manage weeds by Agronomic Practices

In a tea land, weeds become a problem only if the land is not fully covered by tea bushes. Therefore, the best way to control weeds in a mature tea field is keeping the land free of vacancies.

If this is a new clearing, thatching is a good practice, not olny to control erosion and/or as a organic matter source, to control weeds. Controlling weeds in a young tea land also helps tea plants withstand drought conditions.

Manual weeding is recommended in tea plantations, where, scraping is highly demortivated since this increases the soil erosion.

Not all the naturally grown plants are considered as problamatic weeds. Soft weeds such as Centella spp., etc. can be remained in the tea field since they do not compete with the tea bushes for water, nutrient, etc.

Mechanical means of Tea Harvesting

Plucking is the most labour intensive operation in a tea plantation when it is done manually. Bud with with immature one or two leaves is the best time of plucking or picking of tea leaves. Mechanical ways of harvesting now popularizing in asian countries with the scarcity of labour for field operations. Countries near to the equator, enjoy sunshine and rainfall in higher intensities, all over the year. With this climatic conditions, mechanical ways of harvesting of tea shoots, makes bushes debilitated and reduction in yield by around 20-30%. Therefore, mechanical harvesting is recommended only in rush crop seasons.

Small hand-held tea shoot picker (battery powered, one man operation, light weight)

Gasoline powered, large-scale shoot picker

Shear harvesting of tea shoots

Tractor type riding harvester

Agronomic Practices for High Yielding Tea Plantation

This blog is meant for discussing proper agronomic practices applied in tea cultivation, where you can discuss and have answers for tea related agronomic and other problems.