Browsing by Author "Samarappuli, L."
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Item Can rubber be grown successfully in marginal dry areas(Rubber Research Institute. Agalawatta, 1998) Samarappuli, L.Item Comparison of the effectiveness of liquid and granule fertilizer mixtures on rubber plants raised by young budding technique(Rubber Research Institute. Agalawatta, 1997) Dharmakeerthi, R.S.; Yogaratnam, N.Y.; Samarappuli, L.; Silva, S.N.; Yakandawala, A.Effectiveness of granule fertilizer mixtures was compared with currently used liquid formulations on plants raised by young budding technique.Granule formulations are agronomicaly effective provided that they are applied in small quantities.Urea based mixtures was found to be comparatively mire detrimental than sulfate of ammonia based mixtures when used at concentrations higher than the recomended levels.Currently recommended fertilizer schedule with liquid formulations was the most effective programme for young budding among the treatments tested.Reduced frequency of application increased the deiback percentage significantly.However,it could be applied at two-week intervals instead of weekly intervals equally effectively,thereby reducing the application cost almost by half.Item The contribution of rubber plantations towards a better environment(Rubber Research Institute. Agalawatte, 1996) Samarappuli, L.Item Distribution of Mn and Zn in rubber growing soils and its status in relation to selected management practices(Rubber Research Institute. Agalawatta, 2000) Samarappuli, L.; Perera, A.M.A.; Lalantha, H.K.; Rajapakse, W.Item Economics and efficiency of fertilizer utilization in immature rubber(Rubber Research Institute. Agalawatta, 2000) Samarappuli, L.Item Economics and efficiency of fertilizer utilization in mature rubber(Rubber Research Institute. Agalawatta, 2000) Samarappuli, L.Item Effect of soil moisture on establishment success of different planting techniques in rubber(Rubber Research Institute. Agalawatta, 1993) Samarappuli, L.; Yogaratnam, N.; Hettiarachchi, R.Item EL-NINO. its effects on rubber plantations(Rubber Research Institute of Sri Lanka. Agalawatta, 1998) Samarappuli, L.Item Fertilizer to fields designated for seed collection in Hevea(Rubber Research Institute of Sri Lanka. Agalawatta, 2001) Samarappuli, L.Item Land and soil requirements for optimum growth and productivity of rubber under Sri Lankan conditions(Rubber Research Institute of Sri Lanka. Agalawatta, 2001) Samarappuli, L.Item Leaf water potential and stomatal conductance of rubber (Hevea brasiliensis) as influenced by soil moisture and leaf age(Rubber Research Institute of Sri Lanka. Agalawatte, 1987) Samarappuli, L.Stomatal conductance and transpiration and leaf water potential of rubber (Hevea brasiliensis), clone PB 86, subjected to water stress were measured with a steady-state porometer and a pressure bomb, respectively. In well watered plants young leaves showed a higher stomatal conductance than mature leaves. In water stressed plants young leaves always exhibited a lower stomatal conductance than mature leaves. Increase in soil dehydration reduced the leaf water potential, stomatal conductance and the rate of transpiration.Item 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.Item Mucuna bracteata. ideal cover crop for efficient soil and water management in rubber cultivation(Faculty of Agriculture,University of Ruhuna. Kamburupitiya, 2003) Samarappuli, L.; Karunadasa, P.; Mitrasena, U.; Shantha, N.Item Mulching with paddy straw. to reduce immaturity and improve yeilds(Rubber Research Institute of Sri Lanka. Agalawatta, 1995) 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 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 Potassium. its status in rubber growing soil of Sri Lanka(Rubber Research Institute. Agalawatte, 2004) Samarappuli, L.; Edirimanna, V.; Thevarapperuma, A.Item Preliminary studies on the use of neutron probe in some rubber growing soils(Rubber Research Institute. Agalawatta, 1992) Samarappuli, L.; Yogaratnam, N.; Karunadasa, P.; Mitrasena, U.Studies carried out on the use of Neutron Probe in soil/water relations indicate that this can be used as an effective technique in immature Hevea plantations. It had been possible to establish a fairly reliable calibration curve for the subsurface soil 10 - 160 cm the calibration curve obtained is moisture content, Qv = 0.52 CR - 0.39, where CR stands for Count Ratio. It appears that during dry period, distances varying from 0 - 1.2m from the trunk of the tree are suitable for assessing the water content of the soil profile. The available soil water storage capacity of 104.2 mm with the upper lower limits of 235.5 131.3mm, respectively, is likely to be the amount of water that is available to the plants, both rubber covers over a period of 12 months.Item Role of potassium on growth and water relations of rubber plants(Rubber Research Institute. Agalawatta, 1993) Samarappuli, L.; Yogaratnam, N.; Karunadasa, P.; Mitrasena, U.; Hettiarachchi, R.Item Root development in Hevea brasiliensis(Rubber Research Instutite. Agalawatte, 1996) Samarappuli, L.