Rubber Science

LONG- TERM PERFORMANCE OF TWENTY CLONES OF HEVEA BRASILIENSIS UNDER LARGE-SCALE TRIAL IN INDIAResearch Articles
Pages 51 - 57
J.G. Marattukalam, M.A. Nazeer, P.J. George & T.R. Chandrasekhar
- Abstract
- Keywords
Long-term growth and yield performance of twenty Hevea brasiliensis clones were evaluated in two trials in the traditional rubber growing zone of India. Yield, growth and secondary characters like tapping panel dryness and diseases were monitored. In Trial I, mean yield (g/t/t) ranged from 32.1 (IAN 45-873) to 47.7 (RRIM 703). Only four clones viz., RRIM 703, RRIM 701, Harbel1 and GT 1 yielded significantly more than the control clone PR 107. Girth of the trees recorded at 22 years from planting revealed significantly higher values for GT 1 (95.2 cm) than the control PR 107 (89.1 cm). In Trial II, the mean yield ranged from 41.3 (RRII 44 and PB 260) to 52.7 g/t/t (PR 255) in panel BO-1, from 46.8 (PR 260) to 61.6 g/t/t (PB 310) in panel BO-2 and from 47.6 (RRII 45) to 68.4 g/t/t (PB 310) in panel BI-1. Girth at 21 years ranged from 76.9 cm for RRII 105 to 105.0 cm for RRII 44. The results indicated that none of the clones tested were outstanding in their overall performance.

Clones, Growth, Hevea brasiliensis, Large-scale trial, Yield

SUBSTITUTION OF POTASSIUM WITH SODIUM AS NUTRIENT FOR THE GROWTH OF RUBBER SEEDLINGSResearch Articles
Pages 58 - 61
Elsie S. George, K I. Punnoose & M. Karthikakuttyamma
- Abstract
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A study was conducted in a rubber nursery to find out the effect of substitution of varying levels of potassium (K) with sodium (Na) on the growth and nutrient uptake of rubber seedlings as well as on soil properties. The experiment was repeated for two years at the same site. The stem diameter of seedlings was not influenced by the substitution of K with Na. Application of 50 and 75 kg K/ha along with 25 and 50 kg Na/ha had a positive effect on the K content in stem and root of rubber seedlings. The application of 75 and 100 kg K alone and combination of 50 kg each of K and Na gave higher K uptake over control. For 75 and 50 kg K/ha application, an increase in soil available K status was noted with 25 and 50 kg Na/ha application while available Na, pH and electrical conductivity (EC) remained unaffected.

Hevea brasiliensis, Potassium, Rubber seedlings, Sodium uptake

EFFECT OF ORGANIC MANURE ON GROWTH OF IMMATURE RUBBERResearch Articles
Pages 62 - 67
Phebe Joseph, K.I. Punnoose, K. Pratapan, Joshua Abraham, Mathew Joseph, M.D. Jessy, Sherin George, Ramesh B. Nair, Joseph John & T.P. Mathew
- Abstract
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In a field experiment to evaluate the effect of farmyard manure application on soil nutrient status and growth of immature rubber in a field where Mucuna bracteata was maintained as cover crop, it was observed that the application of organic manure through farmyard manure did not improve the growth of plants or chemical properties of the soil.

Growth, Immature rubber, Mucuna bracteata, Organic manure, Soil nutrient status

FIELD PERFORMANCE OF HEVEA TREES RAISED THROUGH UNCONVENTIONAL NURSERY TECHNIQUESResearch Articles
Pages 68 - 72
J. G. Marattukalam, Y.A. Varghese, M.A. Nazeer & T.R. Chandrasekhar
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In a study on the effect of nursery practices on growth and yield of Hevea brasiliensis trees it was observed that the field performance of bench-grafted plants is comparable to that of nursery grafted plants. The practice of high budding and different methods of deep planting had no influence on growth of budded stumps in the field. Polybag plants exhibited superiority in growth over budded stumps during the initial stages. There was no uprooting of plants irrespective of the treatments.

Bench-grafting, Budding, Deep planting, Field performance, Hevea brasiliensis

EVALUATION OF CRUMB RUBBER FACTORY SLUDGE AS MANURE FOR RUBBERResearch Articles
Pages 73 - 80
Elsie S. George, Annie Philip, K.I. Punnoose & M. Karthikakuttyamma
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An incubation and a nursery trial were conducted to evaluate the sludge obtained from settling tanks of crumb rubber factories as a source of nitrogen in comparison with urea. Results of the incubation study indicated that the release of inorganic nitrogen from sludge was slow and steady for 75 days. Nursery trial conducted on the same bed for three years indicated that sludge can be effectively used either in combination with urea, or singly at higher concentration to improve growth of young rubber. The sludge acts as a slow but steady source of nutrients for young rubber.

Crumb factory waste, Growth, Hevea brasiliensis, Inorganic nitrogen, Rubber nursery, Sludge

PRELIMINARY INVESTIGATIONS ON THE ALLELOPATHIC TENDENCY OF MIKANIA MICRANTHA, A COMMON WEED IN YOUNG RUBBER (HEVEA BRASILIENSIS) PLANTATIONSResearch Articles
Pages 81 - 83
Mini Abraham & C.T. Abraham
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Mile-a-minute weed (Mikania micrantha H.B.K), a fast growing herbaceous climber, is a noxious weed in agricultural and non-agricultural areas of Kerala, India. The allelopathic effects of M. micrantha when used as fresh mulch, incorporated in soil and as water extracts of the weed (0, 1, 2 and 4 percent) were studied using test crops (cowpea, rubber and rice). M. micrantha had negative allelopathy on rubber (Hevea brasiliensis) seedlings, causing reduction in height and weight of seedlings. On the contrary, it had positive allelopathy on growth of rice and neutral effect on growth of cowpea. The study indicated that the infestation of M. micrantha in rubber plantation or in nursery may have deleterious effect on growth of H. brasiliensis. It also showed that this weed can be utilized as green leaf manure for rice without any adverse effect on the crop.

Allelopathy, Cowpea, Hevea brasiliensis, Mikania micrantha, Rice