Browsing by Author "Samaranayaka, K.T.T."

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    Phosphorus Behavior in Boralu Series Soil of Rubber (Hevea Brasilliensis) Plantations
    (Uva Wellassa University of Sri Lanka, 2015) Samaranayaka, K.T.T.
    Monoculture cropping system adopted for more than hundred years in rubber [Hevea brasiliensis (A. Juss.) Muell. Arg.] plantation with same agro-management practices has resulted in nutrient imbalance due to either depletion or accumulation of nutrients in soils. Phosphorus (P) is an essential macro nutrient for rubber plantations. This study was carried out to investigate the behavior of P in rubber plantations with respect to Boralu series soil of Sri Lanka. In most rubber growing soils P availability is very low and added P fertilizers become unavailable for the rubber plants due to strong fixation into Fe and Al oxide minerals prevalent in these soils. The study was carried out on Boralu series soils in Geekiyana kanda, Eladuwa, Raigama and Dartonfield estate in Kalutara district. Variation found in the fields was further confirmed by the chemical and physical analyses conducted in the laboratory. Thus, some important chemical analyses, for example, pH, CEC, organic carbon, available P and some important physical analyses such as moisture content and bulk density of soils were carried out. The 48 soil samples representing boralu series soil was evaluated and data were derived via descriptive analysis and a regression analysis. According to results, a significant (P<0.05) difference was observed between the inside and outside of manure circle for pH buffering capacity and organic carbon content whereas no significant (P>0.05) difference between the inside and outside of manure circle could be observed for the moisture content, available P, bulk density and cation exchange capacity. There was a positive correlation between organic carbon and available phosphorus with R2=0.27 by action of phosphorus solubilizing microbes. There was a negative correlation between the available P and bulk density with R2=0.25.Results shows that available P content increase with soil organic matter. Keywords: Available phosphorus, Boralu series soil, Bulk density, Organic carbon, pH
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    Phosphorus Behaviour in Boralu Series Soil of Rubber (Hevea brasiliensis) Plantations
    (Uva Wellassa University of Sri Lanka, 2020) Samaranayaka, K.T.T.; Herath, H.M.S.K.; Senevirathna, A.M.W.K.; Hettiarachchi, R.P.; Silva, E.D.; Edirimanna, V.
    Monoculture cropping system adopted for more than a hundred years in rubber (Hevea brasiliensis) plantation with same agro-management practices has resulted in nutrient imbalance due to either depletion or accumulation of nutrients in soils. Phosphorus (P) is an essential macronutrient for rubber plantations. The main objective of this study was to determine P behaviour in Boralu series soil in relation to soil pH, organic carbon, available P, moisture content, cation exchange capacity, and bulk density. Forty-eight soil samples representing Boralu series soil were evaluated for available P by NH4F/HCl and organic carbon by the Walkley Black method. Descriptive statistical data were derived and a regression analysis was also carried out to find a relationship between soil parameters. Available P varied from 30.77mg kg-1 in manure circle and 23.20mg kg-1 outside the manure circle. Organic carbon content in both areas, in and out of the manure circle, varied from 1.16 to 1.16%. Significant (p=0.03) differences were observed between the inside and outside the manure circle for organic carbon content. Whereas no significant differences between the inside and outside of manure circle were observed for the moisture content (p=0.31), available P (p=0.37), and cation exchange capacity(p=0.13). There was a positive correlation between organic carbon and available phosphorus with R2=0.27 by the action of phosphorus solubilizing microbes. There was a negative correlation between the organic carbon content and soil pH with R2=0.27as well as available P and bulk density with R2=0.25. Results show that available P content increase with organic matter. Keywords: Available phosphorus, Boralu series, Bulk density, Organic carbon, pH