Browsing by Author "Korah, P A"

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Characterisation of soil and irrigation water of the sugarcane belt in Palaghat in relation to yield, nutrient uptake and quality of the cane
(Department of Soil science and Agricultural chemistry, College of Horticulture, Vellanikkara, 1995) Visveswaran, S; Korah, P A
The investigation undertaken, envisages the characterization of the soil and irrigation water of three sugarcane growing regions namely Vannamada, Meenakshipuram and Attapadi in Palghat district and their relation to the nutrient uptake, yield and quality of sugarcane. One hundred and ninety seven surface soil samples (0-15cm) from the three regions were characterized for the major physico- chemical properties. Twenty four farmer’s plots were identified as observation plots to assess the yield, dry matter production and quality parameters of sugarcane juice and the inter relations between these parameters. Samples of irrigation water from four commonly used sources namely bore well, open well, canal, and river water used for irrigating sugarcane plots were collected in the pre monsoon and monsoon periods for determination of quality parameters and to study their effects on the crops. The soils of the three regions were predominantly mildly alkaline in reaction. The EC of these soils were on par with each other and were with in safe limits. The major texture of soils of the area was sandy clay loam, followed immediately by sandy loam. The bulk density, particle density and pore space of the three region did not vary significantly. The water holding capacity and volume expansion of the soils were significantly higher in Vannamada and lowest in Attapadi regions. None of the physical properties had any adverse effect on the growth of sugarcane. Organic matter, total N, P and K recorded low values in soils of the three regions. The rating of available N was medium in all the three regions. For available P and K, the rating for Vannamada and Meenakshipuram regions was medium while for Attapadi it was high. Available S followed the same trend as that of the major nutrient elements and its status in the soils of the three regions was above the critical level. Exchangeable Ca and Mg dominated in all the three regions. Exchangeable Mg and Na were significantly higher in the soils of Vannamada. The levels of micro nutrients viz. Fe, Mn, Zn and Cu in the soils of the three regions were above the sufficiency limits. The quality parameters of irrigation waters such as pH, EC, CI- and SO4- -contents, RSC and SAR studied were within the safe limits for the irrigation of sugarcane. All the three regions recorded high values in yield and dry matter production. However, in comparison Attapadi registered lower values than the other regions. The uptake of N, P, K, Na, Ca and Mg were highest in soils of Meenakshipuram and lowest in Attapadi region. The yield and dry matter production exhibited a significant positive correlation with uptake of N, P, K and Na. The uptake values obtained for micro nutrients were low, which may be attributed to high pH of the soils. Soil of the three regions did not show any significant variation in juice quality parameters such as brix, pol value, purity and commercial cane sugar content. Juice quality parameters were significantly and positively correlated with N, P, K and Na.
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.
Inter-relationship between organic carbon, nitrogen, organic phosphorus and organic sulphur in two red loam soil series of South Kerala
(Kerala Agricultural University, 1991) Korah, P A; Usha, P B; Sudharmai Devi, C R
Mineralisation of nitrogen from non-edible oil cakes in medium black calcareous and lateritic soils
(Kerala Agricultural University, 1988) Korah, P A; Shingte, A K
An investigation on the mineralisation of nitrogen from 6 non-edible oi| cakes, viz., neem, karanja, pilu, kusum, pisa and castor in two typical soils, viz., medium black calcareous and lateritic soils revealed that among the various cakes used, neem cake was the highest in , ; > release of ammoniacal nitrogen followed by karanja, castor, pilu, kusum and pisa respectively in the descending order in both the soils. Lateritic soil was found to be a batter arnmonifier than medium black calcareous soils. The rate of nitrification was highest in neem cake followed by castor, karanja, pilu, kusum and pisa cake respectively in the descending order, in both the soils. Medium black calcareous soil was found to be a better mtrifier than lateritic soil. The total mineralised nitrogen from all the cakes was higher in medium black calcareous soil than in the lateritic soils. In both the soils, neem cake was the highest in this respect followed by castor, karanja, pilu, kusum and pisa cake in the descending order.
Morphological and physico-chemical properties of denuded forest soils under the influence of oilpalm plantation
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1989) George Jose; Korah, P A
A study has been made on the soils of Yeroor estate of Oil palm India Ltd., Bharatheepuram, Quilon District, Kerala State with a view to assess the effect of oil palm plantation on their morphological, physical and chemical characters and the mineralogical set up of the Clay fraction. Four profile pits were dug in each of the four age group plantations, viz., the 4, 8, 12 and 16 year old oil palm plantations and the adjacent denuded area without plantations, and morphological studies carried out. Soil samples from three layers, viz., surface (S), subsurface (SS1) and subsoil (SS2) were studied for their physic - chemical properties. The clay fraction of the soil from the upper two layers of the representative profiles of the denuded forest area and the oil palm plantations was separated and analyses for its mineralogical set up. The study revealed that in all the layers of denuded forest area, as well as in the plantations, the soils contained appreciable quantities of gravel. Distribution of gravel in general, showed an increasing trend with depth. There was significant variation in the properties of silt and clay with the age of the plantation and also with depth. The bulk density and particle density increased with depth in the profiles. The bulk density as well as particle density was highest and volume expansion was the lowest in the 8 year old plantation which is probably caused by a fundamental difference in the chemical nature of this plantation from that of the other plantations. The highest CEC was observed in the soils of denuded forest containing the highest organic matter. The decrease in CEC with the age of plantation and depth of soils may be attributed to a corresponding decrease in organic matter. The soils of the denuded forest were slightly more acidic than the soils of plantations due to the higher content of organic matter. Soils of the 12 year plantation had the highest pH and correspondingly the lime requirement was lowest for these soils. The pH was found to decrease with depth. The CEC and the lime requirement also showed a decrease with depth in the profiles. The decrease in CEC with depth explains the downward decrease of the lime requirement. Both total and available nitrogen and C/N ration decreased with the age of the plantation and with depth. A similar trend was shown by organic carbon also. Total phosphorus showed variation with the age of plantation but the variation did not show any regular pattern. Hence it is difficult to attribute it to the effect of the growth of palms. The second layer of all profiles contained more of total phosphorous. This may be due to the removal of phosphorous from the surface layer by annuals and from the deeper layer by the deep rooted perennials leaving the intermediate layer enriched with respect to total phosphorous. Available phosphorous remained constant in all the profiles. However in the 16 year old plantation there was a sudden decrease in its value which might be due to plant removal. Available phosphorous decreased with depth of soil in all the profiles. As the organic matter and consequently the organic forms of phosphorous have been decreasing with depth, there has been a corresponding decrease in available phosphorous also. Total potassium remained somewhat constant irrespective of the age of the plantation and there was a slight accumulation of total potassium in the intermediate layer. Exchangeable potassium varied in an irregular manner with the age of the plantation but with depth it decreased steadily. Total calcium and magnesium also showed no regularity in variation with the age of the plantations. Both total calcium and magnesium were highest in the surface layer. Exchangeable calcium and magnesium varied irregularly with the age of the plantation, but both of these elements decreased steadly with depth of the soil. Total iron and aluminium were lowest in the 8 year old plantation. Total iron increased steadily with depth down the profile, whereas total aluminium showed a slight decrease in the second layer and then an accumulation in the third layer of the profile. The variation in the exchangeable iron and aluminium with the age of the plantation did not show any regular pattern. However there was a steady decrease in both exchangeable iron and aluminium with depth. Analytical results of the clay indicate that the clay is predominantly of the 1:1 type. The chemical character of the clay from various soils did not show any regular variation with the age of plantation.
On the effect of non edible oilcakes on the respiratory activity of soil
(Kerala Agricultural University, Vellanikara, 1968) Korah, P A; Shingte, A K
Prediction of potassium fertilizer requirement of banana, Musa (AAB Group) 'Nendran'
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1997) Sindhu, J; Korah, P A
A study was undertaken in the field of a local farmer from May, 1995 to January, 1996 to assess the effect of application of different doses of potassium on the growth, yield and quality of bananacv. Nendran. The experiment also envisaged standardisation of the index plant part of K status and determination of K level in index plant part and soil for maximum and economic yield. The experiment was laid out in RBD with five levels of K (0,150, 300, 450 and 600 g K 2O per plant ) as treatments replicated four times . The soil , low in N,P and K status belonged to the taxonomic class Loamy Kaolinitic Isohyperthermic Rhodic Haplustox. All the biometric characters studied namely height of plant , girth of pseudostem, number of functional leaves , total leaf area and leaf area index showed an increasing trend with increase in the dose of K application from 0 to 600 g K2O per plant and the effects were more pronounced from the shooting stage of the crop after it had received the full dose of K supply.
Sulphur status of major uplands of south Kerala
(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1991) Sheeba, S; Korah, P A
A study has been made to determine the different forms and distribution of sulphur, and its relationship to relevant soil parameters in the major upland soils of South Kerala representing sandy, redloam, laterite midland, laterite midupland and forest soils. An attempt was made to study the plant available sulphur by conducting Neubauer technique using paddy as the test crop. Available sulphur in the soils was also estimated using different extractants. The results of the experiments were summarised and appropriate conclusions drawn.