Browsing by Author "Koshy, M M"

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Cation exchange capacity and chemical composition of clay fraction of some important soil groups of Kerala
(Kerala Agricultural University, 1978) Venugopal, V K; Koshy, M M
Cation exchange capacity in relation to the mechanical composition and organic matter status of some soil profiles of Kerala
(Kerala Agricultural University, 1976) Venugopal, V K; Koshy, M M
A study was made of the cation exchange capacity of forty soil samples representing fourteen soil profiles of Kerala in relation to the mechanical composition and organic matter status of the soil. The important findings are summarised below: (1) The cation exchange capacity of the different soil groups exhibited wide variations, the sandy soil recording the lowest and the black soil the highest value. With the exception of black, kari and some alluvial soils all other soil groups gave very low values for this property. (2) Correlation between cation exchange capacity and clay for all the samples taken together was positive and highly significant. The same positive relationship was observed when the individual soil groups were considered. (3) The relationship between organic matter and cation exchange capacity for all the samples together was positive but not significant.
Chemical and mechanical composition of ground dolomitic limestone distributed in Kerala
(Kerala Agricultural University, 1975) Koshy, M M; Vasundhara Bai, B; Sushama, G
Chemical and physico-chemical characteristics of the red soils of Kerala
(Kerala Agricultural University, 1983) Harikrishnan Nair, K; Koshy, M M
Red soils are acidic with low salt concentration. The low contents of organic matter, major nutrients and their low availability, poor cation exchange ca^a^ity and otherexchange characteristics indicate that these are low fertile soils Since the red soils are with good physical properties, the soil productivity can be substantially increased with ths judxious application of organic manures and chemical fertilizers.
Chemical nature of organic complexes in some samples of town compost
(Kerala Agricultural University, 1975) Koshy, M M
Chemical properties of the Poonthalpadam soils of Kerala
(Kerala Agricultural University, 1986) Krishnakumar, A K; Koshy, M M
An investigation on the chemical properties of Poonthalpadam soils of Kerala shows that these soils have a pH range of 6.5—8.4. .The total nitrogen content is low in most of the profiles studied. While the level of total P205 is found to be satisfactory, the available phosphorus content is low probably due to the fact that the P is present in combination with calcium and clay in rather unavailable forms. Tne level of available potassium also is unsatisfactory which warrants potash fertilization. Cation exchange studies reveal that calcium is the predominant cation and 67 percent of the CEC is satisfied by the divalent cations, calcium and magnesium. Sodium is also found to be present in the exchangeable form and in some cases its content exceeded that of magnesium. The poor physical characteristics can be attributed to the presence of sodium, which causes dispersion of clay, and also to the high water table. Organic matter is found to be higher in the surface layers because of the illdrained condition and the wide C/N ratio noticed in some profile samples is possibly due to loss of nitrogen by denitrification and persistence of organic matter due to anaerobic condition. Improvement of the drainage and ameliorative measures for alkalinity are necessary for the reclamation of these soils.
Chromic acid oxidizability of different organic matter fractions in soils
(Kerala Agricultural University, 1973) Koshy, M M
Comparative efficiency of foliar and soil application of complex fertilizers on paddy
(Kerala Agricultural University, 1978) Alice Abraham; Koshy, M M
Comparative study of the nature of acidity in the upland and lowland soils of South Kerala
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1988) Raveendran Nair, A; Koshy, M M
A study has bean made oil the nature of acidity in soils of Kerala in relation to their physiographic positions. Twelve locations from the districts of Trivandrum and Quilon were subjected to the study and from each location soil samples from bottom terrace and upland reaches were collected from depths of 0-20 cm and 20-40 cm. The soils of the uplands and terraces were laterites (Oxisol) in general whereas those of the bottom were of hydromorphic origin (Alfisol/Inceptisol). The soils were analysed to determine the mechanical composition. Chemical properties such as pH, organic carbon, total nitrogen, CSC exchangeable K, Ca, Mg, Ii, A1 and Pe were studied, The neutralisation curve using both calcium hydroxide and sodium hydroxide and permanent and pH dependent charge were also estimated. The mechanical analysis revealed that the sand fraction gradually increased from uplands through the terraces to the bottom areas. The reverse was the case with silt and clay. The variation in silt was statistically significant for topography though it was not so for clay. Organic carbon was significantly higher in the soils of the bottom areas as compared to those of terraces and the uplands. Accumulation in the soils of the bottom areas was due to the anaerobic conditions prevailing under submergence. Organic carbon in general tended to be more in surface soils than in the subsurface layers due to addition of organic matter from the vegetation. Nitrogen showed more or less the same trend as that of organic carbon. As in the case of carbon, the nitrogen content tended to be more in the surface soils than in the subsurface layers. The C/N ratio for the upland was relatively lower than the terraces and uplands due to the greater oxidation of organic matter due to better aerobic conditions. The ratios were much higher than the conventional figure of 10 which nay be attributed to the preferential loss of nitrogen by leaching. All the soils examined were acidic in reaction, Air drying of the soils resulted in a lowering of the pH, Reactions such as the oxidation of ferros iron to the ferric fora and the removal of ammoniacal form of nitrogen may account for this increase in acidity due to air drying.
Distribution and forms of phosphorus in the kole soils
(Kerala Agricultural University, 1991) Sheela, S; Koshy, M M; Korah, P A
The different forms of phosphorus, such as saloid-P, Al-P, Fe-P, reductant soluble-P, occluded-P, Ca-P and organic-P, as well as total-P were determined in the surface and subsur face soils collected from 15 locations in the kole land area of Kerala State. The mean values of the different fractions showed that organic-P was the largest fraction, followed in order by Fe-P, reductant soluble-P, Al-P, Ca-P, occluded-P and saloid P. The most abundant inorganic fraction was Fe-P which constituted 29.75% of the total P in the surface layers and 37.46% in the subsurface layers. Reductant soluble-P constituted 23.91% and 22.16% respectively of the total P in the surface and subsurface horizons. Occluded-P formed 1.81% of the total P in the surface soils and 1.50% of the total P in the subsurface soils. Of the total P, 4.15 and 7.09% respectively were found in the Ca-P form in the surface and subsruface layers. The Fe-P was significantly and positively correlated to the total sesquioxides and the Ca-P was significantly and positively correlated with total CaO.
Distribution fixation and availability of phosphorus in the kole soils of Kerala
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1988) Sheela, S; Koshy, M M
Effect of lime and different forms of phosphorus on the growth
(Department of Soil Science and Agricultural Chemistry,College of Agriculture, Vellayani, 1984) Latha, R; Koshy, M M
A field experiment was conducted in the College of Agriculture, Vellayanl on a sandy clay loam soil (Alfisol) of pH 4.9 to study the effect of three levels of lime,0, 500 and 1000 kg per hectare and three levels of phosphorus, 50, 100 and 150 kg Pg°5 Per hectare in two different forms, on the growth, yield and chemical composition of cowpea. The field trial was laid out as a (3x7) factorial RBD with two replications. The study revealed that lime application significantly increased some of the- growth characters of cowpea. Application of lime at 1000 kg per hectare significantly increased the number of branches on the 60th day of sowing. The highest application rate of 1000 kg per hectare increased the length and dry weight of root on the 30th day, fresh weight of nodules on the 60th day and the number of leaves at all the stages of growth. Liming at 500 kg per hectare increased the yield and yield components of cowpea significantly, such as the dry weight of the pods per plot, weight of seeds per plot and the hundred seed weight. The highest grain yield of 408.3 g per plot (1418.0 kg per hectare) v/as obtained for lime applied at this rate as compared to the control (1172.0 kg per hectare). Lime application at 500 kg per hectare significantly increased the phosphorus content of the plant on the 60th day and the calcium content on the 30th day. The calcium content was Increased on the 45th day also by the highest level of lime application. Lime application at 1000 kg per hectare significantly reduced the potassium content of the plant on the 30th day. Application of lime at 500 kg per hectare significantly increased the phosphorus and calcium contents of the seed. But the magnesium content of the seed was reduced significantly by lime at both levels.
Effect of adding nitrogen in combination with MnO2 on the growth, yield and composition of rice
(Kerala Agricultural University, 1981) Harikrishnan Nair, K; Koshy, M M
Effect of different forms and levels of phosphorus on the growth, yield and composition of three yielding varieties of rice (IR 8, Taichung Native I and Culture 28)
(Division of Agricultural Chemistry, Agricultural College and Research Institute, Vellayani, 1968) Jagadeeschandran Nair, M P; Koshy, M M
To study the effect of different forms and levels of phosphorus on the growth, yield and composition of three high yielding varieties of rice, a pot culture experiment was carried out in the Agricultural College and Research Institute, Vellayani, in a randomised block design with 39 treatments and 3 replications. The different forms of phosphorus used were superphosphate, ultrafos, defluorinated rock phosphate and Thomas phosphate. The levels of application were 0,25, 50 and 75 kg P2O5/ha. The rice varieties studied were Culture 28, IR 8 and Taichung Naive 1. The main findings of the experiment are summarised below: 1) The height of plants was a maximum for IR 8. This growth character was not influenced by the form of phosphorus used, but it increased significantly with increase in the rate of phosphorus application, 2) In the matter of tillers, Taichung Native 1 was superior to IR8 and Culture 28. Of the different forms of phosphorus applied, superphosphate and deflurinated rock phosphate produced the maximum number of tillers. As regards the effect of level, the number of tillers increased with increase in the level of phosphorus application.
Effect of drying and wetting on the physical, Physico-chemical and chemical properties of the submerged soils of Kuttanad
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1988) Raju, P V; Koshy, M M
A study was undertaken at the College of Agriculture, Vellayani to know the effect of drying and wetting on the physico-chemical properties of submerged acid sulphate soils of Kuttanad which are known locally as Kerapadom, Kari and Kayal soils. Random soil samples were collected from various parts of Kuttanad and their physico-chemical properties such as pH, conductivity, available NPK status and different forms of iron and aluminium were estimated in moist state itself. Texturally Kuttanad soils were predominantly of clayay nature. Bulk and particle densities were significantly lower in Kari soils due to high organic matter as compared to Karapadom and Kayal soil. The pH values of Kayal soils were significantly higher than that of Kari and Karapadom soils which were extremely acidic. The conductivity of all soil groups were negligible probably due to seasonal effects and also due to the commissioning of Thaneermukkom bund and Thottapally spillway which prevented the ingress of sea water. The availability of major nutrients was fairly high and no significant differences existed between soils. Exchangeable iron and aluminium varied greatly.
Effect of elevation and rainfall on the physicochemical properties of the soils of the high ranges of Kerala
(Kerala Agricultural University, 1970) Chandrasekharan Nair, K; Koshy, M M
Effect of elevation and rainfall on the physio-chemical properties of the soils of the highranges of Kerala
(Division of Agricultural Chemistry, Agricultural College and Research Institute, Vellayani, 1969) Chandrasekharan, Nair K; Koshy, M M
Effect of lime, phosphorus and rhizobium inoculation on the growth and yield of cowpea
(Kerala Agricultural University, 1982) Samuel Mathew; Koshy, M M
An experiment to study the effects of lime, phosphorus and rhizobium inoculation on the growth and yield of cowpea was conducted at the College of Agriculture, Vellayani during 1979. About 24^ increase in the yield of cowpea could be obtained by the application of lime at 300 kg/ha. Phosphorus application or seed inoculation with rhizobium culture did not produce any beneficial effect on the growth, nodulation or yield of cowpea under Vellayani conditions.
Effect of zinc in combination with lime on the composition of and absorption of nutrients by rice
(Kerala Agricultural University, 1979) Mariam, K A; Koshy, M M
A pot culture experiment was carried out using the Vellayani Kayal soil (Tropaquept) in a randomized block design to study the effect of zinc in combination with lime on the absorption of nutrients by rice. The soil used in the study had a pH of 4.3 and it contained 0.11% N, 0.02% P20S, 0.36% K20r 0.10% CaO, 0.13% MgO and 4.2 ppm available Zn. The levels of zinc used were 0, 10, 20 and 40 Kg ZnS04 7H20/ha and those of lime were 0, 250, 500 and 1009 Kg CaC03/ha. NPK fertilizers (70+35+35 kg/ha) were also applied as per the package of practices. The application of lime did not result in appreciable increase in the pH of the soil under field conditions. The nitrogen content of grain was increased significantly by zinc, but it had no effect on the nitrogen content of straw. Application of lime reduced the nitrogen content of the grain. Zinc tended to decrease and lime tended to increase the P206 content of both grain and straw. But this effect was significant only in the case of grain. The K.,0, CaO and MgO contents of both grain and straw were practically unaffected by the application of zinc and lime. However there was a trend for CaO and MgO to increase in the plant material with increased applications of lime. When the total quantities of nutrients removed per pot was considered there was significant variation only in the case of nitrogen and phosphorus whereas in the case of the other nutrients the treatment effects, were non-significant.
Effect of zinc in combination with lime on the growth and yield of rice
(Kerala Agricultural University, 1977) Mariam, K A; Koshy, M M
A pot culture experiment was carried out using the Vellayani Kayal soil in a randomized block design to study the effect of zinc in combination with lime on the growth and yield of rice. The number of tillers per plant was increased significantly by lime, but not by zinc. Neither lime, nor zinc had any significant effect on the number of productive tillers, whereas these treatments resulted in significant increase in the height of plants. The panicle length was increased significantly by lime and the number of grains per panicle was increased by both lime and zinc. The effect of zinc on the yield of grain and straw was inconsistent whereas the yield of grain tended to increase with increase in the levels of lime.