Browsing by Author "Talibudeen, O."

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    Determination of Active Root Distribution of Hevea brasiliensis using Radioactive Phosphorus
    (1971) Soong, N.K.; Pushparajah, E.; Singh, M.M.; Talibudeen, O.
    Phosphorus uptake by Hevea seedlings from nutrient solution and by mature Hevea trees from the soil was studied using P32 tracer. The usefulness of leaves and latex for detecting PM uptake by Hevea was compared. Latex assay was found to be more convenient and reliable than leaf assay and was used to determine the relative distribution of active roots of Hevea in three different soil zones under study. Maximum root activity was found to be in the first 12 feet from the trees, reflecting past cultural practices. Injection of P32 into the trunk of a mature rubber tree showed translocation into the leaves and latex but no radioactivity could be detected in the roots or in the surrounding soil indicating that trunk injection was unsuitable for estimating the distribution of active roots in soil.
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    K-A1 Exchange Equilibria in Acid Soils of Malaya and the Use of Thermodynamic Functions to Predict the Release of Non-exchangeable K in Soil to Plants
    (1971) Singh, M.M.; Talibudeen, O.
    A thermodynamic treatment of cation exchange equilibria was used to interpret K.-AI exchange equilibria in 0.01N chloride solutions for 9 common acid soils of Malaya. In 7 of the 9 soils, K. was adsorbed more strongly than Al while for the remaining 2, the reverse was the case. The standard free energy for formation of K-soil from Al-soil varied from —2550 to 900 calories!mole. In all soils, the activity coefficient of the adsorbed K ions, fK , first increased and then decreased with decreasing K-satura-tion, while fAit the activity coefficient of the adsorbed Al ions, decreased continuously with decreasing Al-saturation. Between soils, changes in J'K with K saturation varied much more than changes in /A1. Excess free energy functions for.. AI-+K. exchange calculated from ( fK,fAl ) values for the soils showed distinct differences between all soils. For soils containing micaceous minerals, these differences in the surface chemistry of the soils were related to the release of initially non-exchangeable potassium in the soil to Pueraria phaseoloides in glass-house experiments.
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    A Thermodynamic Assessment of the Nutrient Status of Malayan Soils Quantity-Intensity Measurements for Potassium Using Calcium Chloride Equilibriation
    (1968) Mohinder Singh, M.; Tan, K.T.; Pushparajah, E.; Talibudeen, O.
    Quantity /Intensity (Q/I) relationships for potassium status of soils were determined in nine acid soils of Malaya which are known to have widely differing K-status and on which rubber Is commonly grown, by the calcium chloride equilibriation procedure of BECKETT. Quantity. Intensity and Buffer Capacity values derived from these Q/l relationships did not give better relation with the status of soil, as indicated by greenhouse cropping by Pueraria. than the conventional acid-extractable value. The best assessment parameter appeared to be a Buffer Capacity value (B. C. cropping), obtained from greenhouse cropping data and the laboratory measured intensity, although intensity, when taken alone is the poorest Indicator of soil K status as assessed by greenhouse cropping by Pueraria.
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    Thermodynamic Assessment of the Nutrient Status of Rubber-Growing Soils
    (1969) Mohinder Singh, M.; Talibudeen, O.
    Schofield s thermodynamic concepts of intensity and quantity were used for measuring the potassium and phosphorus status of Malayan rubber-growing soils. It was shown that for acid soils in Malaya, intensity and quantity measurements need be done using aluminium as the reference ion instead of calcium used elsewhere. For phosphorus, intensities were measured in dilute ammonium chloride solutions instead of calcium chloride solutions used elsewhere and quantities were measured by isotopic exchange. l These thermodynamic indices and the conventional indices of acid-extractable and exchange-. able values for potassium, and total and available indices for phosphate, which are in current routine use, were related to uptake by Pueraria phaseoloides in the glasshouse. This showed that for assessing the potassium status of Malayan soils, the buffer capacity value obtained from the slope of the quantity! intensity relationship curve was better than the conventional acid-extract-able and exchangeable values currently used for determining the fertiliser requirements of rubber. For phosphorus, both conventional and thermodynamic quantity indices related directly to glasshouse cropping. More work is however necessary for a systematic correlation.