Plantation Crops (2+1)

Shade Management

Shade maintenance and management in tea plantation

Tea requires filtered light and if it is exposed to direct sun its growth is affected. Tea bushes with semi – erect leaves don’t require shade as the leaves are not overheated when exposed and allow more light penetration into the bush. Hence, the tea bushes with semi-erect leaves have highest yield potential as against the types with horizontal leaves. Broad leaved bushes perform better under shade.

Purposes of shade regulation in tea are (Beneficial effects of shade trees in tea cultivation)

1) Protection: To protect tea plants from direct sun and hot weather They help to reduce the injury caused to tea leaves by UV radiation.
2) Fertility improvement: Addition of organic matter in the forms of fallen leaves of shade trees apart from loppings obtained during shade regulation. About 20 to 25 tonnes of leaf litter is added per year out of shade trees. Increase the fertility of soil by adding 8-10 tonnes of organic matter/ha/year.
Note:

1) Fertility breakdown or degradation at 32º C is three times higher than at 16ºC
2) For each 1 per cent increase in organic matter we have to add 22 t of organic matter per ha i.e., @ 2.2 kg per square meter.

3) Breaking up of sub soil: Shade trees break up the heavy subsoil layer due to root penetration.
4) Temperature effect: These trees help to regulate temperature and humidity at bush level

Summer: checks the raising of temperature of plantation during summer up to 5 to 7 ºC compared to open. Day time they reduce the temperature and during night time increase the temperature by 5 to 7 ºC compared to open.

5) Wind breaks: Shade trees serve as wind breaks

6) Erosion control: They also help in minimizing soil erosion.

7) Additional income: As timber, fuel, supporting tree for pepper etc

8) Decrease in pest incidence: Mite (Acaris theae )( Under shade 24 mites per leaf compared to 61 mites under open or unshaded leaves)

9) UV radiation: They help in reducing the injury caused to tea leaves by UV radiation. Shade trees trap 30-40 per cent of full mid day sun thereby minimizing the harmful effects of solar radiation.

10) Increased soil fertility: By adding 8-10 tonnes of organic matter per ha per year.

11) Regulation of humidity and minimized evaporation loss : Shade trees help to regulate temperature and humidity near the bush level apart from minimizing the loss through evaporation and transpiration.