4.Journals Published in Sri Lanka
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Item Rubber plantations as self-sustaining agroforestry systems(Sri Lanka Forest Department:Battaramulla, 1995) Samarappuli, L.; Yogaratnam, N.Item Root development in Hevea brasiliensis(Rubber Research Instutite. Agalawatte, 1996) Samarappuli, L.Item Mulching with paddy straw. to reduce immaturity and improve yeilds(Rubber Research Institute of Sri Lanka. Agalawatta, 1995) Samarappuli, L.Item Plastochron indexes in Hevea brasiliensis growth under two water regimes(Rubber Research Institute of Sri Lanka. Agalawatte, 1987) Samarappuli, L.Rubber (Hevea brasiliensis) plants were grown in two water regimes, so that one treatment (wet plants) received water every other day and other treatment (dry plants) received water every seventh day, during the experimental period. In wet plants, plastochron indexes (PI) advanced more rapidly with time and final leaf size was greater (9.6 cm average). Diminished water supply appears to affect the rate of development and the sequence of developmental events, as observed when plastochron index was plotted against time and when leaf length was plotted against plastochron index of wet and dry treatments. It appears that the plastochron index could be used as a scale for studies connected with the effects of water availability on the development of Hevea brasiliensis.Item Rubber to rescue adverse environmental impacts(Rubber Research Institute of Sri Lanka. Agalawatta, 2009) Samarappuli, L.; Wijesuriya, W.Item Rubber growing soils and their characteristics(Rubber Research Institute of Sri Lanka. Agalawatta, 2000) Samarappuli, L.Item Performance of some RRIC 100 series clones under different soil moisture regimes(Rubber Research Institute. Agalawatta, 1992) Samarappuli, L.; Yogaratnam, N.; Hettiarachchi, R.Results obtained on the performance of recently developed RRIC 100 series clones when sujected to water deficit situations are presented in this paper. The plant diameter of RRIC 121 and RRIC 102 was found to be superior to other clones tested such as RRIC 100, RRIC 110 and PB 86 even at the very low soil moisture level of 10% available water. Similar results were recorded in relation to plan height, number of whorls and relative growth rates of clones RRIC 121 and 102 even under low soil moisture conditions. Data obtained also showed that clones RRIC 102 and 121 had the highest plant nitrogen and potassium contents. Moreover, even under very low soil moisture levels plant P content was greater in clones RRIC 121 and 102. Most of the data on growth are also consistat with the physiological parameters such as leaf water protential (LWP) relative water content (RWC), transpiration rate (TR) and leaf diffusive resistance (LDR). It was further noted that the LWP and RWC were highest while TR was lowest in clone RRIC 102. Moreover, the clone RRIC 102 had the highest LDR compared to other clones, confirming the ability of this clone in maintaining a higher water holding capacity under low soil moisture conditions.Item Towards shorter immaturity and improved yields by mulching with rice straw(Rubber Research Institute. Agalawatta, 1992) Samarappuli, L.; Yogaratnam, N.; Samarappuli, P.; Mitrasena, U.In this study with immature Hevea brasiliensis, multing with paady straw around the base of the tree was found to be a better agronomic practice than growing leguminous cover crops such as Pueraria phaseoloides and Desmodium ovalifolium or allowing natural vegetation to grow in the inter-row area. Girthing had been much higher with mulching which resulted into reduction of the immature, unproductive period by approximately 18 and 12 month in comparison with naturals and creeping legumes respectively. In addition to early tapping, yield of latex was also higher during the early stages, increases in the region of 33perc. and 40perc. in comparison with creeping legumes and naturals respectively. The present value of the benefit achieved from mulching amount to Rs. 31,088/= per hectare of which Rs. 19,740/= is due to extra yield and the balance of Rs. 11,348/= is saving on inputs as a result of early maturity. Consequently, a net present value (NPV) of Rs. 7.8 million at national level can be achieved with the above practice at 50perc. level of adoptionItem Litter accumulation from Mucuna bracteata cover crop and its effects on some soil chemical properties in rubber plantations(Rubber Research Institute. Agalawatta, 2010) Chathurika, S.; Samarappuli, L.; Mapa, R.B.