The use of green manuring crops in tea culture has long been in vogue to safeguard the young tea in nursery from the duress of drought and nutrition- supply. Green manuring crops which are predominately leguminous plants, help enriching the soil –fertility and soil moisture through its lopped materials. These also act as miniature shade trees and protect young plants in the nursery.
In Bangladesh, green manuring crops with leguminous species, like Crotalaria anagyroides, Tephrosia candida (Bogamedeloa) Priotropies cytisodes, Desmodium gyroides, Cajanus cajan (Arhar) etc. are used in newly planted area for soil-rehabilitation.( Sana, 1989.)
A few grasses like Tripsacum laxum (Guatemala), Pennisetum purpureum (Napier), Cymbopogon citratus (Citronella), Cymbopogon winteranus (Lemon grass) are found to be useful for soil rehabilitation..
As cover crops Mimosa invisa, Calopogonium mucunoides, Strylosenthes gracilis are effectively used in tea for conservation. They are twining or prostrating creepers and can smoother any weed including Mikania scandens and Cuscuta within a few months.
Mulching with these crops provides manifold benefits, such as, the addition of organic matter and nutrients check of soil erosion, and suppression of weeds. An estimate of green matter production by these crops per acre of land and the quality of mulched required annually is shown in the table---
1. Mulching Procedure:
All cover crops should be cut down at the onset of an expected period of dry weather. If left standing, they will rapidly depleted soil moisture. For soil rehabilitation and conservation, the process of mulching with lopped cover crops/ green manuring crops at 10-15cm.thickness needs to be continued for a number of years; the usual practice of mulching with jungle materials is not enough for proper soil rehabilitation and conservation. Following procedure may be adopted.
- Edges of exposed tea sections should be mulched during Nov/Mar. in mature tea.
- Single layer of mulching, 3cm. deep, should be done in young tea sections during September.
- Second layer of mulching, 3cm. deep, should be done in young tea during the middle of October.
- Final layer of mulching, 4cm. deep should be done during the first week of November in young tea.
5. Pruning litter should be kept at the top of the mulch until complete defoliation.
Pruning litters of one acre of light pruned area can supply as much as 4 tons of organic matter, 35.5kg. Nitrogen, 16 kg Phosphorus and 28 kg Potash.
- Mulch will be removed during April /May and spread uniformly after application of fertilizers.
