4.Journals Published in Sri Lanka
Permanent URI for this communityhttps://dl.nsf.gov.lk/handle/1/6840
Browse
9 results
Search Results
Item Tea and soil acidity. water culture experiments, II(Tea Research Institute. halawakele, 1928) Gadd, C.H.Item A recent study of the results of some Ceylon tea fertilizer trials(Tea Research Institute. Thalawakele, 1959) Pearce, S.C.Item Manurial experiments on nitrogen, phosphate and potash(Tea Research Institute. halawakele, 1930) Eden, T.Item Economising on phosphate and potash for mature tea -1965(The Tea Research Institute. Talawakele, 1965) Tolhurst, J.A.H.Item Estimation of Nitrate and phosphate leaching from lysimeter simulation of rice straw landfill bioreactor and evaluation of fertilizer quality of resulting compost(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 2011) Gamage, D.A.S.; Wijesekara, S.S.R.M.D.H.R.; Sarathchandra, G.W.N.L.; Basnayake, B.F.A.; Costa, W.A.J.M.Item Comparison of selectively mined apatite crystals and commercially available rock phosphate from Eppawala, as P fertilizers for flooded rice(Postgraduate Institute of Agriculture, University of Peradeniya:Peradeniya, 1994) Ratnayake, M.P.K.; Kumaragamage, D.; Dahanayake, K.Item Removal of phosphate from aqueous medium by dolomite-potential method for treatment of industrial effluents(University of Perdeniya. Peradeniya, 1999) Perera, S.; Priyantha, N.Item Some geological and geochemical attributes of the phosphate deposit at Ridigama, N.W. Sri Lanka(University of Peradeniya. Peradeniya, 1995) Hewawasam, A.L.T.; Dahanayake, K.Ridigama phosphate deposit occurs in the form of apatite rich veins that have intruded into the Precambrian granitic gneisses. Weathering processes active in the tropical Sri Lankan environment have given rise to a residual deposit. This deposit which is a weathering profile contains large primary apatite crystals in a fine matrix composed of ferruginous, siliceous, aluminous secondary phosphate minerals. Chemical studies have revealed that the primary apatite crystals of Ridigama have total P2O5 contents varying from 39% to 41% whereas it is less than 35% in the matrix. The 2% citric acid and water solubilities of primary apatite cystals are around 7% P2O5, and 0.05% P2O5 respectively; for the matrix the values were approximately 4% P2O5 0.04% P2O5 . Neutral ammonium citrate (NAC) solubility exceeds 2.5% P2O5, for crystals and less than 2% P2O5 for the matrix. The primary apatite crystals of this deposit showed higher solubility than those of Eppawala. However, the matrix at Eppawala was more soluble than that of Ridigama. The major components in the primary crystals are hydroxyl chlorapatite and carbonate fluor-apatite. Both these apatite types are associated with crandallite, quartz, feldspar, hematite and magnetite in the fine matrix.Item Role of rock phosphates in the nutrition of immature and mature Hevea(Rubber Research Institute. Agalawatta, 1994) Dissanayake, D.M.A.P. othersCommercially available Eppawela rock phosphate (ERP) was evaluated as a source of P for young rubber plants throughout the period of immaturity. The effects of rock phosphate on yield nutrient composition of leaves soil were also studied on mature rubber.The efficiency of ERP in relation to growth of young plants was similar to that of Imported Rock Phosphate (IRP) Triple Super Phosphate (TSP) when used in soils with a P status less than 37.00 Kg of soils with a soil pH range of 3.6 to 4.2. In these situations it appears that the currently recommended rate of P is unlikely to be sufficient to meet the plant P demand.It is therefore possible to use ERP as a source of P for immature rubber plants growing in areas which are considered low in P for rubber.In contrast, application of rock phosphates did not influence the productivity of the mature rubber tree.plants were able to maintain adequate levels of P in leaves even under no P fertilizer conditions suggesting the effect of residual P in soil that received IRP during the immature phase.