Browsing by Author "Susan Varughese"

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Direct and residual effect of different forms and levels of magnesium on yield and magnesium uptake in rice
(Kerala Agricultural University, 1993) Susan Varughese; Jose, A I
A potculture experiment was conducted using rice as the test crop grown continuously for two seasons to study the direct and residual effect of added Mg under rice culture in waterlogged condition. The performance of the rice plant with respect to yield and Mg uptake was better in karappadam soil during the first crop season; while in the second crop season, it was higher in laterite soil. Different sources and levels of Mg applied did not have any significant influence on yield and Mg uptake of the rice plant. There was no marked difference in total Mg uptake between the two seasons, indicating a substantial release of Mgfrom added sources during the second crop season also.
Forms of magnesium in soil as influenced by added magnesium sources under submerged condition
(Kerala Agricultural University, 1993) Susan Varughese; Jose, A I
A laboratory incubation study was carried out using two acid rice soils of Kerala under submerged condition for 180 days. The soil samples drawn at regular intervals were analysed for chemical forms of Mg. The insoluble Mg fractions dominated over the soluble ones. Acid soluble Mg and mineral Mg together constituted about 74.03 per cent of the total Mg content. Ammonium acetate extractable Mg of the soils was 19.09 per cent. The content of organic complexed Mg was very low and that of water soluble Mg was practically nil. Total Mg content as well as the content of various Mg fractions was higher in karappadam soil than in the laterite soil. The soluble Mg fractions were higher in samples supplied with magnesium sulphate while the insoluble fractions were higher in samples supplied with carbonate forms of Mg. The difference between the Mg levels tried in this experiment became conspicuous only under conditions of prolonged submergence.
Influence of added magnesium sources on soil characteristics under submerged condition
(Kerala Agricultural University, 1994) Susan Varughese; Jose, A I
An incubation study and a potculture experiment were conducted with two acid rice soils of Kerala, using three Mg sources, viz., magnesite, dolomite and magnesium sulphate tried at two levels of Mg (25 and 50 kg MgO ha ) to study the influence of added Mg on soil characteristics. Available Mg of the karappadam soil was significantly higher than that of the laterite soil. There was no significant difference between the three Mg sources with regard to their contribution to available Mg in the soil. But the Mg availability increased with raised levels of Mg application. A negative relationship was noticed between available K and Mg fractions in the soil. Different sources and levels of applied Mg did not have any significant influence on NILjOAc extractable Ca. Magnesium application raised the pH of the soils. Efficiency of the different Mg sources in correcting the acidic soil reaction was in the order of magnesite dolomite magnesium sulphate.
Screening of varieties of ginger and turmeric for shade tolerance
(Department of Agronomy, College of Horticulture, Vellanikkara, 1989) Susan Varughese; Vikraman Nair, R
The present study 'Screening of varieties of ginger and turmeric for shade tolerance' was conducted during May 1988 to February 1989 at the College of Horticulture, Vellamkkara, Trichur. The experiment was laid out in a split plot design with four replications. Thirteen varieties of ginger and twelve varieties of turmeric were raised at shade levels of 0,25, 50 and 75 per cent. For providing shade pandals were erected on wooden frames and covered with coconut fronds to provide the required levels of shade. These were covered on all sides also leaving a clearance of 1 m from ground level. An Aplab lux meter was used for adjusting the shade intensities. Most of the ginger varieties recorded the highest yield at 25 per cent shade and hence these were grouped under the category of shade loving plants. This will qualify this crop as highly suitable for intercropping in coconut gardens. Other yield parameters such as drymatter production and harvest index were also found to be the highest at 25 per cent shade Ginger varieties grown without shade yielded the best quality rhizomes. Significant interaction was noticed between shade levels and varieties on rhizome yield. Valluvanad was selected as the best single variety for all situations. Jamaica also appeared to be almost as good. Three varieties each were selected as suitable for 0, 25, 50 and 75 per cent shade. These are Jamaica, Valluvanad and Kuruppampadi for 0 per cent shade; Valluvanad, Pottangi Selection 667 and Jamaica for 25 per cent, Jorhat, Valluvanad and Jamaica for 50 per cent and Valluvanad, Jamaica and Jorhat for 75 per cent shade.
Suitability of magnesite as a source of magnesium in acid rice soils of Kerala
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1992) Susan Varughese; Jose, AI
An incubation study and a potculture experiment were conducted to assess the suitability of magnesite in comparison with that of magnesium sulphate and dominate in karappadam (Moncompu, Alappuzha district) and laterite (Vellanikkara, Thrissur district) soils of Kerala. In the incubation study, these three Mg sources were added to the two soils at the rate of 25 and 50 kg MgO ha-1 and their transformations under submergence were studied for 180 days drawing samples at regular intervals of 15 days. The samples were analysed for Mg fractions, available Ca and K, pH and EC. In the potculture experiment using rice (Annapoorna) as the test crop, the direct and residual effectof magnesite, dolomite and magnesium sulphate were studied. The soils and levels of Mg application were the same as in the incubation study. Application of N, P and K was done uniformly in all the treatments . Soil and plant samples were taken at 15 days interval for the determination of uptake and avilability of nutrients , pH and EC. The residual effect of Mg fertilizers was assessed by continuing the experiment for the second season without the addition of Mg fertilizers.