Rubber Science

ESTIMATION OF BIOMASS IN HEVEA CLONES BY REGRESSION METHOD: RELATION BETWEEN GIRTH AND BIOMASSResearch Articles
Pages 113 - 116
D. Chaudhuri, K.K. Vinod, S.N. Potty, M.R. Sethuraj, Jacob Pothen & Y.A. Nanja Reddy
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- Keywords
The relationship between girth and the above ground biomass was studied in two clones, with varied growth habits, of Hevea brasiliensis. The clones chosen were RRIM 600 and RRII 118. A set of relationships were developed using the boimass as a power function of girth for different age groups from first year after planting upto fifth year. The regression equations were found non-significant for individual clones as well as for years from second year onwards. A general equation was thus developed and is given as biomass in g(W) = 2.278479 X^2.2683(where, X is the girth at 15 cm height from bud union). The relation is found to be good fit from 16 cm or more girth, and is location specific.

Hevea brasiliensis, Girth, Biomass, Regression model

EFFICACY OF DIURON FOR WEED CONTROL IN RUBBER SEEDLING NURSERYResearch Articles
Pages 117 - 122
Radha Lakshamanan, K.I. Punnoose & M. Mathew
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A field experiment was conducted to study the effectiveness of three doses of Diuron viz., 1.0, 2.0 and 2.5 kg per ha for controlling weed growth in rubber seedling nursery. Application of diuron at the rate of 2.5 kg per ha at planting, could control weeds effectively for a period of 120 days and was significantly superior to the lower doses tried. Single application of diuron at the rate of 2.5 kg per ha gave a cost saving of 29.9 per cent over the manually weeded plots. Application of Diuron at the rate of (2.5 kg per ha) at planting followed by a second application at the rate of 1.0 kg per ha after two months controlled weeds effectively and resulted in a total weeding cost saving of 55.8 per cent over manual weeding. Herbicide application followed by mulching was also equally effective and economical in controlling weed growth. No phytotoxic effect was noticed on the seedlings from application of the herbicide.

Weed control, Seedling nursery, Diuron, Mulching, Hevea

A COMPARATIVE EVALUATION OF ISNR 20 WITH CONVENTIONAL FORMS OF NATURAL RUBBERResearch Articles
Pages 123 - 129
K.T. Thomas, L. Varghese, Toms Joseph, K.N. Madhusoodanan & N.M. Mathew
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A detailed study was undertaken to compare ISNR 20 with the conventional forms of natural rubber. Samples from different sources were collected periodically over a period of one year and the raw rubber, processing and vulcanizate properties were evaluated. It was found that the sheet grades show better raw rubber properties except volatile matter and initial Wallace plasticity than ISNR 20 and EBC IX. It has also been found to have comparable level of consistency in these properties with that of ISNR 20. The vulcanizate properties including ageing characterisitics have also been found to be better for sheets. Significant differences were not observed among ISNR 20 made out of raw materials collected from estate and non-estate sector

Natural rubber, ISNR, RSS, EBC, Raw rubber, Processing properties, Ageing

EFFECTS OF LIMING ON NUTRIENT UPTAKE, BIOMASS PRODUCTION AND NODULATION IN PUERARIA PHASEOLOIDESResearch Articles
Pages 130 - 134
Annie Philip, Mercykutty Joseph, K. I. Punnoose & Antony P. Antony
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Potculture experiments were conducted to study the effects of liming on the growth of Pueraria phaseoloides and on the changes in soil chemical properties. Liming significantly increased the dry matter production and nodulation of P. phaseoloides. The availability of P, K, Ca and Mg in soil increased significantly by lime application. Liming showed a positive effect on the uptake of N, P, Ca and Mg but had negative effect on the uptake of K.

Lime requirement, Dry matter production, Nodulation, Cover crop, Rhizobium, P. Phaseoloides

DTPA EXTRACTABLE SOIL MICRONUTRIENTS IN THE TRADITIONAL RUBBER GROWING REGIONS IN INDIAShort Scientific Reports
Pages 135 - 139
Mercykutty Joseph, M.P Prasad, Antony P. Antony & K.I. Punnoose
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PRELIMINARY STUDIES ON PREPARATION OF LUBRICATING GREASES FROM BLEACHED RUBBER SEED OILShort Scientific Reports
Pages 140 - 141
O.U Njoku & I.C. Ononogbu
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