The paper attempted a short-term review of the import restriction for tyres brought in by the Government. The paper reveals that the policy change has considerably reduced import of tyres into India and has contributed positively towards achieving its perceived objectives of protecting and nourishing the domestic tyre manufacturing sector. But the benefits being enjoyed by the tyre manufacturing sector due to the import restriction, which is the major consumer of NR in the country, has not percolated to the upstream rubber production sector, as there exists significant difference in price of NR in the domestic and international markets. Lower price of NR in the international market depresses price in the domestic market badly affecting the production sector. Hence, suitable policy interventions are suggested to support the domestic rubber production sector.

Rhizosphere is an important zone of nutrient changes and nutrient activity of plants. The nutrient release, uptake and the chemical activity in rhizosphere are species specific and the changes are in the immediate vicinity of roots. Hevea brasiliensis, the important source of natural rubber, generally grown in acidic soils  is a major crop of economic importance in the major rubber growing countries viz. Thailand, Indonesia, Malaysia, China, Vietnam and India.  Repeated cycles, heavy rainfall and topographic conditions lead to excessive acidification and nutrient removal from soils that limits the crop growth and productivity.  The present attempt was to know the changes in the rhizosphere pH and nutrient availability and growth of rubber (Hevea brasiliensis) seedlings as influenced by three soil pH viz. extremely acidic (pH 4.4), strongly acidic (pH 5.5) and neutral soil (pH 7.4) with varying base status. Seedlings were raised in polybags and nutrient status in the rhizosphere at the beginning of the experiment and at intervals of three months and eight months were monitored.  It was observed that the extremely acidic pH (4.4) was modified to a pH of around of 5.1 in the strongly acidic range and the neutral pH (7.4) was changed to acidic range (6.2).  Soil organic carbon, the major soil health index, was maintained in the initial medium status in all the three soils. The available calcium and magnesium content of the extremely acidic pH and strongly acidic pH were improved whereas the very high status of the neutral soil was decreased significantly.  Modifications in the availability of other nutrients were also observed.  The observed alterations in the rhizosphere is suggestive of specific rhizosphere adaptations of the rubber plants for extremely varying soil conditions. In extremely acidic soil alkalinization occurred and in neutral soil, acidification occurred when rubber seedlings were grown for eight months.  However, the fact that the strongly acidic soil (pH 5.5) did not change, indicated that pH near 5.5 was favorable for growth of rubber seedlings.  The study indicated that specific adaptations were operating in the rhizosphere of natural rubber plants to modify the pH and nutrient availability for initial establishment and growth.

An intercropping experiment was conducted with a variety of annual and perennial fodder crops (fodder maize, fodder cowpea, hybrid napier and para grass combination, guinea grass, signal grass and Stylosanthes combination) under immature rubber.  This study includes the adaptability of these fodder crops under immature rubber along with other parameters like herbage yield, nutritive value etc. Five different fodder crops were grown in the rubber interrow space under rectangular planting geometry i.e. 3.4 x 6.7 m. It is concluded that, among the fodder crops cultivated for three years, performance of guinea grass in terms of herbage yield was superior (i.e. 437 q ha-1 annum-1 as intercrop and 521 q ha-1 annum-1 as monocrop) than other fodder crops. It was followed by signal and Stylosanthes combination i.e. 405 q ha-1 annum-1 and 490 q ha-1 annum-1 in intercrop and monocrop plots respectively.  Thus, these combinations under immature rubber holds good potential for increasing the forage production and can bridge the gap in demand and supply of cattle feed in the fragile ecosystem of Tripura.  Moreover, the mean girth of rubber was comparable for intercropped (27.8 cm) and monocropped (27.4 cm) area and no major changes in soil physio-chemical property were observed.

Extraction of silica from rice husk ash (RHA) is a sustainable route for the manufacture of silica and it is also a solution for the disposal of large amount of rice husk (RH) generated from paddy fields. The objective of this work was to isolate the silica from RHA and to explore its use as a filler in rubber products. Accordingly, a chemical method was proposed for the preparation of silica by dissolving RHA in sodium hydroxide followed by filtration and  precipitation using sulphuric acid with 85 per cent yield. The cure characteristics and mechanical properties of natural rubber vulcanizates loaded with RHA silica in comparison to those prepared using Ultrasil VN3 grade silica were examined.  The compounds reinforced with RHA silica showed fast cure behaviour compared to Ultrasil VN3. The mechanical properties of rubber vulcanizates reinforced with RHA silica were comparable with Ultrasil VN3. Experiments with prevulcanized latex showed that RHA silica can be used as a potential filler for conventional latex products. The overall results indicated that RHA can be used as a cheaper filler for both latex and dry rubber products.

Latex is a colloidal suspension or emulsion of water insoluble substances in an aqueous phase, synthesized and / or stored in an internal secretory system called latex vessels or laticifers present in a number of annuals and perennials. Among the different constituents of latex, natural rubber has been found in the latex of over 895 species of plants belonging to 311 genera of different families.  In some genera, the young tissues produce abundant laticifers, but later become lignified, whereas in many other plants including Hevea brasiliensis, (prime source of natural rubber), latex is produced throughout their life time. Because of the occurrence of latex in specific tissue system and its biosynthesis occuring throughout the life of the plant, different functions such as protection, conduction, water regulatory system, food reserve, substitute, by product, excretion etc. are assumed for latex. Latex cannot be regarded as excretory material because of its occurrence in a pre-determined internal tissue system. Under normal exploitation the plant is capable of regenerating the drained latex without any sign of necrosis while abnormal functioning of cambium can result from over exploitation as observed in Hevea brasiliensis.