Journal of the Rubber Research Institute of Sri Lanka

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Author: search.filters.author.Waidyanatha, U.P. De S.Has files: Yes

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    Studies on inoculation of cover legumes for improving nitrogen fixation
    (Rubber Research Institute. Agalawatta, 1977) Waidyanatha, U.P. De S.; Pathiratne, L.S.S.; Ariyaratne, W.A.
    Many rhizobial strains were screened for their nodulating ability against Pueraria, Centrosema, Calopogonium and Desmodium spp. using seedlings grown in nutrient agar. Pueraria in pots but not in the field. This is probably due to natural populations of rhizobia in the soil which were able to successfully compete with the introduced strains in nodulating on the legume. There was evidence that indigenous rhizobia themselves formed effective nodule and fixed nitrogen.
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    Effect of leaf litter on direct and indirect mobilization of P from apatite
    (Rubber Research Institute. Agalawatta, 1987) Pathiratne, L.S.S.; Waidyanatha, U.P. De S.; Peries, O.S.
    Leaf litter as direct and indirect means of improving P availability from apatite was tested. Application of leaf litter impo=roved the P uptake by indicator crops but did not influence the availability of P from applied apatite.
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    Virgin bark tapping of some RRIC 100 series clones
    (Rubber Research Institute. Agalawatta, 1987) Samaranayake, C.; Waidyanatha, U.P. De S.; Pathiratne, L.S.S.; De Soysa, A.G.A.
    All RRIC 100 series clones reached tappability much earlier than the two control clones viz. RRIM 600 and PB 86. Significantly higher yield per tree per tapping was obtained in the first year on a 1/2 S d/3 system compared to 1/2S d/2 tappings in many of the clones tested. However, during the second year there was no significant differences in yields obtained on both frequencies indicating that the tree was able to replenish the latex removed in a tapping, much faster than in the first year of tapping. The data presented indicate the possibility of tapping all recommended clones on 1/2S d/32 system of tapping from the second year, without any adverse effects.
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    Responses of five tropical pasture species to application of apatite
    (Rubber Research Institute. Agalawatta, 1986) Pathiratne, L.S.S.; Waidyanatha, U.P. De S.; Peries, O. S.
    Shoot growth and phosphorus content of Pueraria, Centrosema, Stylosanthus, Panicum and Paspalum were best at 500ppm and better at 100ppm than at zero ppm apatite. Root growth on the other hand was stimulated at 100ppm and marginally inhibited at 500ppm.Both relative shoot and root growth responses were least for Styl;osanthus which showed a notable ability to take up P from untreated soil compared to the other species. This may be related to its greater calcium uptake ability as evidence d in much higher calcium concentrations in its shoot than in the other. The grasses recovered for more P from both treated and untreated soil than the legumes.
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    Effect of vesicular-arbuscular mycorrhizae on seedling of Hevea and Pueraria phaseoloides
    (Rubber research Institute. Agalawatte, 1984) Jayaratne, A.H.R.; Peries, O.S.; Waidyanatha, U.P. De S.
    Hevea seedlings showed a slight growth responce when inculated with Gigaspora margarita out of four species, tested in sterilised soil. There were no significant differences in the uptake of nutrient by mycorrhizal Hevea plants. Non-mycorrhizal Pueraria plants grew very poorly unless they were given liberal quantities of phosphate fertilizer, confirming previous reparts. All mycorrhizal plants took up more nutrients from soil than non-mycorrhizal plants. Effective nodule formation wassignificantly grater in mycorrhizal plants when phosphorus was added.
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    Utilization of phosphorus from apatite and growth of plants inoculated with vesicular arbuscular mycorrhiza and phosphate dissolving bacteria
    (Rubber Research Institute. Agalawatta, 1990) Pathirana, L.S.S.; Waidyanatha, U.P. De S.; Peiris, O.S.
    An annual grass, Pennisetum ploystechyon (L) Schult and a perennial creeping legume Pueraria phaseoloides took up more P and grew better in an acid soil (pH 4.8) treated with a poorly soluble source of apatite. Inculation of the sterilized soil with a heterogenous mixture of a vesicular arbuscular mycorrhizal (VAM) spores extracted from the soil and with Glomus fasciculatus (E3) spores did not increase plant growth or uptake of P in soil with apatite but growth was increased considerably in soil in soil without apatite. However, inoculation with E3 type spores had no effect on growth or P uptake of Pennisetum . Phosphate dissolving bacteria (PDB) stimulated growth of Pueraria and uptake of P from a soil enriched with apatite.