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1978 - 19792
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Subject: Soil Science and Agriculture Chemistry × End date: 1979 × Start date: 1978 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Foliar diagnosis, yield and quality of ginger(zingiber officinale ROSCOE) in relation to nitrogen, phosphorus and potassium
    (Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1978) Johnson, P T; KAU; Jose, A I
    A field experiment was carried out at the Instructional Farm, attached to the College of Horticulture, Vellanikkara during 1977 – 78 to study the effect of graded doses of nitrogen, phosphorus and potassium on the growth, yield and quality of ginger and also to develop suitable foliar diagnosis techniques in relation to these nutrient elements. The treatments comprised of three levels each of nitrogen (40, 80 and 120 kg N/ha), Phosphorus (30,60 and 90 kg P2 o5/ha) and potassium (40,80 and 120 kg k2o/ha). The experiment was laid out in a 33 factorial experiment in randomised block design confounding the affect of interaction NP2K2 totally. The results revealed that among the morphological characters studied, only the height of tiller and total dry matter of the plant were markedly influenced, while other characters like number of tillers and number of leaves per tiller were not effected. Of the fertilizer treatments, nitrogen at 80 kg/ha significantly affected these two characters, while the effect of phosphorus and potassium were not significant. Application of nitrogen at 80 kg/ha significantly increased the rhizome yield of the crop, while the levels of phosphorus and potassium employed failed to influence the yield. Uptake of nitrogen and phosphorus by the plant was significantly influenced by the application of nitrogen at the rate of 80 kg/ha, whereas the graded doses of phosphorus and potassium had no significant influence in this respect. The uptake of potassium on the other hand was not influenced by any of the fertilizer treatment introduced. The total period of growth put under observation appeared divisible into three phases with respect to the development of aerial tissues namely, a phase of active vegetative growth (90th to 120th day after planting); a phase of slow vegetative growth (120th to 180th day) and a phase approaching senescence (180th day to harvest). The pattern of the rhizome development followed the same trend as that of the aerial tissue, but instead of a final phase of insignificant growth, the development of rhizome continued till harvest. The uptake of nitrogen, phosphorus and potassium progressively increased with advancing period of group growth. There was marked uptake of these nutrients by the plant during the period of active plant growth (90th to 120th day after planting). The uptake of nitrogen, phosphorus and potassium in leaf and pseudostem progressively increased upto 180th day and then decreased while their uptake in rhizome steadily increased till harvest. The content of nitrogen phosphorus and potassium was highest in the top most leaves and continuously decreased with increasing number of the leaf position, when the leaves are numbered from top to bottom of the tiller. In consideration of the stability of nutrient level with leaf positions and sensitivity or correlation with varying doses and uptake, the group of 5th to 12th leaves appeared to be the best suited for foliar diagnosis of N, P and K status of the crop. The period between 90th to 120thday after planting was recommended as the optimum period for the detection and amendment of the nutrient status of the crop. The graded doses of nitrogen, phosphorus and potassium and their interaction failed to influence the percentage oleoresin content of ginger.
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    ThesisItemOpen Access
    Evaluation of available phosphate reserve of soil by chemical methodes
    (Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 1979) Mathew, Jacob K; KAU; Jose, A I
    A laboratory study including a pot culture experiment was carried out using 18 lateritic soil to evolve a suitable laboratory chemical method as an index for the estimation of available phosphate reserve (Ra-value). The total plant removable phosphorus of the soils was determined growing rice (variety IR-8) continuously in soils taken in pots, till the content of phosphorus in plants became below the critical level. The pot culture experiment was designed in completely randomized design with 18 treatments (soils) and 3 replications. To evolve a suitable extractant for the estimation of “Ra-value” H2SO4 and HCI at different concentrations and combinations were tried. Out of the 29 extractants employed, 17 were selected based on their consistence in the pattern of phosphorus release and the amount of phosphorous extracted. From a pilot study, in which different organic acids at different concentrations were screened, oxalic acid at the strength of 0.05 N was selected as the best chelating agent to be employed with the 17 mineral acid combinations. The results showed that compared to Bray No.1, the performance of HCI was very poor and had only a little pronounced influence on the extraction of phosphorus. Sulphuric acid at analogous concentrations extracted higher quantities of phosphorus and obtained better correlations with phosphorus uptake values at the end of 6th crop. Combinations of mineral acids extracted higher quantities of phosphorus from soil than the individual acids, with a pronounced influence at lower concentrations. The pattern of release of phosphorus fluctuated widely when the mineral acids were used individually, but the degree of fluctuation was considerably less when employed in combination. In all the above cases the major part of phosphorus was extracted within 30 minutes and thereafter the release was very slow. The pilot study employed in the selection of organic acids for chelated system, to prevent the resorption of phosphorus into the soil from the solution, revealed that resorption of phosphorus from the solution can be effectively prevented by employing organic acids; the amount of phosphorus extracted by the mineral acids can be increased by the presence of organic acids notably oxalic acid and acids at the strengths of 0.05 N were as good as 0.10 N in their effects on the extraction of soil phosphorus. A period of equilibration not less than 30 minutes was considered critical and optimum. The extractant No.10 (0.06 N H2SO4 & 0.06 N HCI in 0.05 N oxalic acid) was found to be superior to the remaining combinations and gave better correlation with “Ra-value” of the soil. Phosphorus extracted by Bray No.1 failed to correlate significantly with phosphorus uptake by crops in soil groups in which the percentage phosphorus content of plants were below 0.025, 0.05 and 0.2 showing that Bray No.1 is not an efficient extractant for the estimation of “Ra-value” of the soil. Thus the present study recommend the extractant 0.06 N H2SO4 and 0.06 N HCI in 0.05 N oxalic acid with an equilibration period of 30 minutes and soil solution ratio 1 : 10 as a better method for estimating the “Ra-value”. Regression equation between phosphorus extracted by this method and “Ra-value” of the soils selected was rather narrow, the application of this equation in predicting the possibility of skipping phosphorus application in soils appeared very much limited.