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ThesisItem Open Access Quality and fatty acid composition of coconut oil in relation to varietal variation and mineral nutrition(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1994) Geetha Kumari, V S; KAU; Ranjendran, PCoconut is a perennial oil seed crop with a large number of cultivars having widely varying growth and yield characteristics. It is both an agricultural and industrial crop with immense economic importance. A variety of edible oils are available in the market today with wide variations in quality parameters and nutritional characteristics. Although product quality is influenced by many factors associated with production, harvesting, curing and processing; quality is influenced to a greater extent by the genetic parameters and chemical composition. Assessment of quality parameters and fixing standards for the nutritional aspects are to be considered with top priority for the development of new varieties/cultivars along with the yield attributes. Considering the afore mentioned facts in view, it was felt essential to study the effect of varietal variation and mineral nutrition on the oil content, quality and fatty acid composition of coconut oil. Nuts collected from different varieties/cultivars from RARS, Pilicode, Instructional farm, Vellayani and palms of an ongoing fertilizer trial of the CRS, Balaramapuram, were subjected to chemical analysis to study the above aspects. The results of the analysis were summarised and appropriate conclusions drawn. The effect of varietal variation on the oil content and quality parameters like acid value, saponification value and iodine value were found to be significant. Minor quality parameters like Reichert – Meissel and Polenske value also showed considerable differences among the varieties. The fatty acid composition of oil from selected varieties also had shown considerable variation. The effect of mineral nutrition on the oil quality and fatty acid composition of coconut oil were found to be insignificant. The oil content was not influenced by nitrogen and phosphorus while potassium had a significant but negative effect on oil content. The influence of N, P and K fertilizers on the quality parameters like acid value, saponification value and iodine value was not significant in general. Minor quality parameters like Reichert – Meissel and Polenske value showed variation due to fertilizer treatments. The fatty acid composition of oil from selected treatments. The fatty acid composition of oil from selected treatments were also influenced by mineral nutrition. From the results of the study it can be concluded that quality parameters of coconut are much influenced by varietal differences than by mineral nutrition. Thus it is evident from the study that the genetic variability has got a greater role to play in modifying quantity parameters and chemical composition of the most important tropical adible oil namely coconut oil. Selection and breeding should be directed towards tailoring new varieties with higher oil content, quality indices and fatty acid composition.ThesisItem Open Access Standardisation of plant part as an index of potassium status in banana, musa (AAB Group) nendran(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1994) Sumam George; KAU; Padmaja, PA field experiment in Musa (AAB group) Nendran, the most popular commercial fruit crop of Kerala was undertaken from August, 1991 to May, 1992 with seven graded levels of K as treatments replicated thrice. The soil, medium in N and P and high in K status belonged to the taxonomic class ‘loamy kaolinitic isohyperthermic aeric tropic fluvaquents’. The effects of higher levels of K on all important growth characters of the crop like height of pseudostem, girth of pseudostem at different heights from the ground level, total number of leaves, number of functional leaves, total leaf area, leaf area index and total dry matter production were more pronounced from the shooting stage of the crop after the plants had received the full dose of K supply. Uptake of major nutrients N, P and K showed increasing trend with increase in K supply. Uptake of Ca showed a negative relationship with increasing K application while Mg uptake showed an inconsistent pattern. Uptake of micronutrients Fe, Mn, Cu and Zn were maximum at K3 level of application (225 g K2O plant-1). Soil content of available K increased while exchangeable Ca and Mg contents decreased at higher levels of K supply. The maximum bunch yield of 26.18 t ha 1-which was significantly higher than all other treatments was recorded at K3 level (225 g k2O plant-1) This level also resulted in maximum values for all the yield attributing characters like number of hands bunch-1, number of finger bunch-1, weight of hand, length of finger, girth of finger and weight of finger. By adopting this recommendation a net fertilizer saving of 75g K2O plant-1 Can be achieved which is equivalent to 312.5 kg of muriate of potash costing Rs. 2000 at the present market rate. Over and above this, increase in yield obtained by doing so is 4500 kg ha-1. Additional income that could be generated by the way of sale of this at the rate of Rs. 8 kg-1 works out to Rs. 36000. Thus a total saving of Rs. 38000 ha-1 can be achieved by following the suggested recommendation. Path coefficient analysis of yield attributes showed that the character number of finger bunch-1 is having the maximum direct effect on yield followed by girth of fruit and weight of fruit. Quality characters of the fruit namely total and non reducing sugars, shelf life and flesh peel ratio showed significant and positive trend towards K nutrition. Correlation coefficient were worked out between bunch yield and important crop characters. Balance sheet of nutrients in soil after harvest of the crop was worked out to assess the final soil status of nutrients in relation to the initial status. Petiole of the third leaf up to shooting stage of the crop and that of the flag leaf there after was selected as the index of K status of the plant as the K content of the same was found to hold the maximum relationship with bunch yield at all the growth stages. The critical K levels in the petiole for maximum yield as well as maximum response to fertilizer application at each stage were determined which were found to be 1.30 per cent and 1.02 per cent respectively at early vegetative stage, 1.28 per cent and 1.06 per cent respectively at late vegetative stage, 1.80 per cent and 1.36 per cent respectively at shooting stage, 2.43 per cent and 1.98 per cent respectively at post shooting stage, 2.50 per cent and 1.80 per cent respectively at bunch maturation stage and 2.47 per cent and 1.80 per cent respectively at harvest stage. The critical K content in soil for economic yield worked out to 286.5 kg K2O ha-1 at early vegetative stage, 276.5 kg K2O ha-1 at late vegetative stage, 271.o kg K2O ha-1 at shooting stage, 239.o kg K2O ha-1 at post shooting stage, 245.0 kg K2O ha-1 at bunch maturation stage and 236.0 kg K2O ha-1 at harvest stage. Graphs were plotted relating petiole K content to soil K content at important growth stages of the crop based on quadratic regression models to provide information on soil K content at a particular stage if the petiole K content at that stage is known. Linear regression models were developed relating soil K content to fertilizer dose to find out the quantity of fertilizer to be applied to bring the soil level to the critical level.ThesisItem Open Access Foliar diagnosis and yield prediction in sugarcane in relation to N,P and K(Department of Soil science and Agricultural chemistry, College of Horticulture, Vellanikkara, 1994) Ramesh, V; KAU; Suman Susan, VargheseA field trial to study the relationship of sugarcane yield and nutrient status through foliar diagnosis was carried out at Sugarcane Research Station, Tiruvalla during 1992, with the hybrid variety COTI 88322 (Madhuri). The experiment was laid out in a 33 factorial randomised block design consisting of three levels each of nitrogen (0, 165.0 and 330.0 kg N/ha), phosphorus (0, 82.5 and 165.0 kg P2o5/ha) and potassium (0, 82.5 and 165.0 kg K2o/ha). In order to standardise the leaf position, the leaf that just began to unroll (spindle like) was taken as the first leaf and the second, third, fourth, fifth and sixth leaves were counted from first leaf below. At the end of germination phase only third, fourth and fifth leaves were collected as no sixth leaf was found at this stage and from the second stage onwards the sixth leaf was included in the study. For standardising the best season suited for the collection of leaf and to predict yield, samples were collected at six different stages of plant growth. The stages of sampling were : (1) germination phase (2) Tillering phase (3) At the beginning of grand growth phase (4) After grand growth phase but before flower formation (5) After flower formation but before maturity phase and (6) At the time of harvest. Attempts were made to find out the direct and indirect contributions of N, P and K in different leaves with and without sheath on yield and to predict yield based on the step-wise regression analysis. Attempt was also made to fine out the influence of leaf nutrient content at different leaf position collected at various stage of sampling on the nutrient uptake of sugarcane. Studies were also made to find out the influence of different levels of N, P and K on cane juice quality and nutrient uptake of sugarcane at harvest stage. Observations revealed that the N content in the leaf with sheath varied from 0.35 to 1.41 per cent, while it was from 0.53 to 1.58 per cent for leaf without sheath. The N content of leaf with sheath showed a gradual decline with age of crop while the N content in the leaf without sheath increased from first to third stage and there after decreased. The differences in the levels of N applied reflected in N content of leaves at the second and third stage of sampling. The P content in the leaf with sheath varied from 0.056 to 0.166 per cent and the leaf without sheath varied from 0.088 to 0.161 per cent. Phosphorus distribution at different leaves in all the stages were rather inconsistent in both the cases. The response to the different levels of P applied was more pronounced in the second stage of sampling. Potassium per cent in leaf with sheath varies from 0.33 to 1.16 per cent while it was from 0.39 to 1.04 per cent for leaves without sheath. The content of potassium in the leaves without sheath was low in all the stages compared to leaves with sheath. The decrease in K content with age was not conspicuous. The effect of different levels of K was clearly reflected in the fourth stage of sampling. Results also showed that the extent of role played by the NPK content of leaves with sheath on yield at the first, third and fifth stages of sampling was low while the NPK content of leaves without sheath at the first and fifth stage of sampling had a little influence on final yield of sugarcane. The nitrogen content in the fourth leaf with sheath and third and fourth leaves without sheath collected at the second stage of sampling established a significant influence on the yield of sugarcane. The P and K contents of the fifth leaf with sheath collected at the second stage of sampling established a significant effect on yield of sugarcane. Observations revealed that among the stages of sampling, the second stage is recommended for N, P and K, Regarding the leaf positions, the third, fourth and fifth leaves without sheath is ideal for diagnostic purpose in relation to N, while the above leaves with sheath is ideal for diagnostic purpose in relation to K. For P, the fifth leaf with sheath is found to be the best. Stepwise regression model fitted with yield and percentage of nutrients in different leaf positions at various stages of sampling gave a maximum prediction of 73 per cent (R2 = 0.7297) when the nutrient content of the third, fourth and fifth leaves collected at the second stage of sampling was considered. The nitrogen content at the third and sixth leaves without sheath collected at the second and fifth stages of sampling had a significant correlation with the nutrient uptake of sugarcane at harvest stage. The different treatments of NPK failed to play a significant influence on the brix, pol and CCS per cent of cane juice.ThesisItem Open Access Pedological investigation on the ecosystem of vellayani lake(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1994) Sanjeev, V; KAU; Thomas, VargheseLakes play the important role of storing the rain water and maintain the ground water table in the adjoining areas. They form a fragile ecosystem which reflect the nation’s ecological wealth. Lakes, in India cover 0.2 million ha. In Kerala, there are 10 fresh water lakes. During the recent past, due to population pressure, vast areas of lakes and other wetlands have been filled and reclaimed either for human inhabitation or for agricultural activities, resulting in serious ecological changes. Vellayani lake, which is the only fresh water lake in Trivandrum represents one of the worst affected ecosystem in Kerala. Not much have been studied about the different ecological and pedological aspects of this lake. The present study was undertaken to throw light on the nature of land use and characteristics of Vellayani lake ecosystem, the production potential of the soil, and the extent of degradation of the lake ecosystem. Nine locations were selected to represent both the Kayal lands as well the lands reclaimed by human activity. Profiles were taken from these locations and the samples were analysed for different physic – chemical characteristics. Water and soil samples were collected from the lake periodically and analysed for seasonal changes in pH, EC, chloride and sulphate. Climatological data of the station was also collected. Results of the study prove that the lake ecosystem is fast degrading. Remote sensing techniques coupled with ground truth analysis have shown that 60% of the original lake area has been reclaimed. Due to heavy siltation, the average depth of the lake has been reduced to 3 m. Rainfall pattern of the location for a period of 11 years shows a drastic decline in the annual precipitation and the mean values has come down to 1520mm from 1840mm since 1982. Coconut is the predominant crop around the lake and the fringes of the lake have been reclaimed for different land uses. The predominance of crops in the reclaimed area are in the order rice, coconut, mixed trees, mixed crops, banana. The water quality analysis has shown that the water is free from salts and can be safely used for domestic purposes as well for irrigation. The pedological investigations on the lake soil system indicated that the lake bed soil is of recent origin and belongs to acid hydomorphic group. According to U.S. Soil taxonomy it can be classified as fine. Kaolintic, isohypertheremic, acidic, tropic, fluvaquents. The lake bed is a highly productive soil system which can be better utilised for aquaculture rather than agriculture considering other ecological and environmental factors. The step to abandon dewatering of the Kayal for cultivation has been a bold one from the part of the authorities and this coupled with other scientific conservation methods will prove a great deal in preserving this fragile ecosystem for future generations.ThesisItem Open Access Potassium release and exchange characteristics of the selected wetland rice soils of Kerala(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1994) Louis, Joseph; KAU; Babukutty, KBeing in the humid tropics, the pedogenic environment prevailing in kerala keeps the soil inherently deficient in the status of potassium. The exchange and release patterns of potassium was studied using typical wet land soils viz. Black cotton soils of Chittoor, sandy Onattukara of Kayamkulam and laterite alluvium of Pattambi. This investigation gives a deeper insight into the potassium supplying capacity of these soil types of Kerala. From the basic chemical analysis of the soils, it was revealed that the black cotton soils are high in clay content (%) and potassium fixation and supplying capacity are also high. In sandy Onattukara the clay content is very low (15 %) and hence the fixation and potassium content were found to be low while in lateritic alluvium eventhough the clay content is high (25%) the potassium content and fixation is low due to the kaolinitic nature of the clays. A study on the cumulative potassium removal by continuous flooding with water and leaching with neutral normal ammonium acetate revealed that the total potassium removed by seven successive leachings to be 12.8 mg, 2.28 mg and 11.4 mg k in black cotton, sandy Onattukara and lateritic alluvium soil respectively. But the potential capacity of supplying k in these soils as estimated by chemical analysis was found to be 85.5, 31.0 and 29.5 mg k/kg soil indicating a situation where the analytical procedures give much higher estimate than that is actually available under field conditions. From another experiment to find the total potassium supplying capacity of these soils by crop exhaustion studies, it was found that the total potassium supplied by these soils amounted to 306, 15.44 and 14.27 mg k/kg soil. However the black cotton soil alone remained undepleted even after seven successive cropping with rice. The high amount of potassium supplied by Black cotton soil was due to the high content of fixed k, while in sandy Onattukara and lateritic alluvium the low content of fixed potassium, low clay content and low CEC explains the low availability of potassium. When we compare the amounts of potassium obtained by crop exhaustion with the amount of k removed by leaching it may be noted that leaching studies provided an under estimated value. This might be due to the reversible equilibrium possible between soils k and that extracted by ammonium acetate during leaching, where as under exhaustive cropping the plant root continuously removed k from the system there by creating a concentration gradient between soil K and solution rendering no chance for such an equilibrium. The response studies carried out in the above depleted two soils – Sandy Onattukara and Lateritic alluvium with different levels of applied K (0 k, ¼ k, ½ k, 1 k, 1 ½ k, and 2 k. Where K represents cumulative K removal by crop exhaustion) showed that biometric characters, yield attributes and nutrient content showed an increasing trend with increase in the levels of applied K. The response was maximum at 2 K levels. The response applied K showed a linear pattern.
