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ThesisItem Open Access Soil nutrirent dynamics in cocoa(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Smitha, B; KAU; Wahid, P AAn investigation on the dynamics of soil nutrients in the rootzone of cocoa (Theobroma cacao) was conducted during 1993 – 94 at the College of Horticulture, Vellanikkara. Soil and leaf samples were taken from cocoa trees under the Cadbury – KAU Co – operative Cocoa Research Project, Vellanikkara. Cocoa variety used for the study was forastero. The soil of the site was laterite (Oxisol). The treatments consisted of factorial combinations of N, P and K fertilizers each at two levels (with and without), two levels (with and without) of irrigation and shade and seven age groups namely 1, 3, 4, 5, 6, 9 and 12 years. Soil samples were also collected from an uncropped and unfertilized area nearby. The impact of long – term inorganic fertilization, irrigation and shade and age of the tree on soil chemical characteristics as well as foliar nutrition of cocoa influenced by long – term inorganic fertilization, irrigation and shade were assessed. Continuous application of urea for a period of nine years increased soil acidity and availability of P, S, Fe and Mn. It also increased total soil P and Fe. But it resulted in depletion of available K, Ca, Mg, Zn and Zn and Mn reserves of the soil. Long – term application of superphosphate resulted in the build – up of available and total P in soil. It also improved the status of soil available Ca, S and soil reserves of Ca and S. But it depleted soil available and total K, available and total Zn, available Mg and Cu and total Mn. Muriate of potash application increased the available and total K content of the soil. On the other hand it caused depletion of available P, Ca, S, Mn, Cu and soil Ca and Mg reserves. Interactions among urea, superphosphate and muriate of potash were also significant with regard to the fertility of the cocoa rootzone is concerned. Increasing soil acidity due to urea application, enrichment of S and Ca due to superphosphate application, and decrease in available P and S due to muriate of potash application were highly influenced by depth. Regular irrigation over a period of five years resulted in reducing the availability of P, Ca, Mn and Cu. It also reduced the total P and Mn in soil. But available K, Zn, S and total S tended to increase with irrigation. In the irrigated plots, total and available P were significantly lower in the surface layers compared to that in unirrigated plots. Provision of shade for a period of 13 years resulted in the build – up of soil organic carbon, available P, Fe and soil reserves of P, Ca, S, Fe, Zn and Mn. On the other hand it decreased the concentrations of available and total K, available S, and Zn and total Mg. Irrigation x shade interaction significantly influenced the available P content of soil. Urea application increased the foliar concentrations of N, Fe, Mn and Cu, but it decreased the leaf K content significantly. Long – term superphosphate application reduced Zn content of cocoa leaf. Application of muriate of potash increased leaf K content, but depressed foliar mg content significantly. Leaf N and K contents of cocoa were highly influenced by N x K interactions. N x P interaction significantly affected foliar Zn concentration of cocoa. Foliar Zn recorded higher values in plants receiving no nitrogen and phosphorus. Irrigation resulted in increased foliar concentrations of almost all nutrients except that of Ca and Mg. Foliar Ca content was higher in unirrigated plants. Effects of irrigation on leaf Mg was not significant. Cocoa trees under shade recorded higher concentrations of N, P, Mg, Fe and Mn and Cu in their foliage while K content was higher in open grown plants. Irrigation x shade interaction significantly influenced foliar N content. Shaded and irrigated conditions resulted in highest foliar N content. Nutrient dynamics in rootzone of cocoa over a period of 12 years of crop growth and fertilization could be described by linear or quadratic model. The linear model was found to be a better fit for available and total K, available and total Mg, available Cu and total Zn. In the case of available and total P, available and total Ca, available Zn, total S and total Cu the changes in concentrations with time could be described by a quadratic model. Available Mn content of the soil showed steady increase with age up to nine years followed by a sharp decrease.ThesisItem Open Access Fertility investigation and taxonomy of the soils of banana research station Kannara(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Sreerekha, L; KAU; Marykutty, K CTaxonomy and fertility investigation of the soils of Banana Research Station, Kannara, was the main intension of the present investigation. Representative surface soil samples were collected from each block of this research station, namely A, B, C, D, E and F for investigating the fertility status of soil. Profiles considered for the study were P1 and P2 in A block, P3, P4 and P5 in B block, P6 and P7 in C block, P8 in D block, P9 in E block, and P10 in F block. Profiles were excavated to study the characteristics of each of the horizons in the soil profile and classify the soils of each block. After the collection and preparation of soil samples, laboratory analyses were carried out as per the standard methods. With an increase in depth, profile samples showed an increasing intensity of colour of the horizons and increase in clay content whereas a decreasing trend was noticed for apparent density, absolute density, water holding capacity and pore space. Soils were acidic and low electrical conductivity values were observed. Organic carbon and total nitrogen decreased with depth. Total P2o5 content was lower than total K2o. Low reserves of total nutrients were observed for other elements also. Sesquioxide content was very high and intermediate layers showed maximum accumulation. In surface as well as profile samples the predominant cation was calcium followed by magnesium. A general increase of CEC and ECEC with depth was observed. Oxalate extractable iron content was lower than the dithionite extractable iron. Distribution of total iron was irregular. Surface soil showed wide variation in texture. Clay content showed significant positive correlation with water holding capacity whereas silt and organic carbon failed to impart any influence upon the same. Phosphorus fixing capacity was high for all the samples. DTPA extractable micronutrients were more than the adequate amount. Based on the soil test values fertilizers were recommended for various blocks. Nitrogeneous fertilizers can be reduced by 5 to 10 per cent. Applications of phosphatic fertilizers can be reduced by 75 per cent in most of the blocks. Potassium fertilizers can also be reduced considerably. Nutrient indices were calculated and a soil fertility map was drawn. Classification of pedons of various blocks according to soil taxonomy has been attempted and found that P1 of A block belongs to the order Entisol. P2 (A block), P3, P4 and P5 (B block), P6 and P7 (C block), P9 (E block) and P10 (F block) belong to the order Alfisol. P8 of D block belongs to the order Inceptisol. By this investigation, the classification of soil profiles were done and the fertility status of each block was found out. In accordance with the soil test values, fertilizer recommendations were made. Thus, by reducing the inputs, cost of cultivation could be reduced considerably.ThesisItem Open Access Vertical movement of nitrogen in major rice soils of Kerala(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1995) George Abraham, T; Kau; Pushkala, SAn experiment was conducted at the College of Agriculture, Vellayani, to assess the leaching and runoff losses of applied fertilizer nitrogen in typical, major rice growing soils of kerala, with varying physical and chemical properties. Undisturbed vertical columns were used for the leaching study. The runoff study was conducted as a pot experiment using surface soil samples. The study revealed that the Onattukara soil recorded the highest leaching loss of applied nitrogen (56.10%). Kayal soil showed the lowest leaching percentage of 24.21. The quantity of leachate collected per unit time was also found to be the maximum in the case of Onattukara soil (185.51 ml/hr) and least in the case of Kayal soil (155.60 ml/hr). Correlation studies revealed that the leaching loss of nitrogen was negatively correlated with organic matter (-0.5593), cation exchange capacity (-0.4560), clay (-0.5864), bulk density (-0.3213) and water holding capacity (-0.5544). The leaching loss was positively correlated with the quantity of leachate collected per unit time (+0.8876). In the case of Onattukara and kole soils, the loss of nitrogen through leaching was observed till the fifth day. For Kari soils, the loss stopped completely by the 10th day. The Karappadam and Pattambi soils showed leaching till the 15th day. However, in the case of Kayal soils, the leaching loss continued through the whole period of the study. In all cases, maximum amount of leaching occurred during the first five days after fertilizer application and after that the loss was in negligible quantities. In the case of runoff study also, Onattukara soil showed the highest runoff loss of applied nitrogen (40.41). The least loss was shown by karappadam soil (15.70%). The runoff loss was found to decrease with increase in number of days. Even though, Karappadam soils showed the lowest runoff loss of applied nitrogen, it had the highest percentage difference in runoff loss (77.8%) and the least was shown by Onattukara and Pattambi soils (63.5%). Correlation studies revealed that the runoff loss of fertilizer nitrogen was found to be negatively correlated with the oprganic matter (-0.1248), cation exchange capacity (-0.0324), clay (-0.4135), water holding capacity 9-0.6723) and bulk density (-o.4659).ThesisItem Open Access Vermicomposting of vegetable garbage(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1995) Anina Susan, Zachariah; KAU; Prabhakumari, PAn economically feasible method of composting, utilizing earthworms and beneficial micro organisms was standardized to produce an enriched organic manure and its efficiency was tested on a vegetable crop (Chilli). Comparison of the biomass production potential of earthworms and the composts produced by them were carried out in an experiment in CRD with three treatments and seven replications. The efficiency of the epigeic earthworm species, Eudrilluseugeniae in composting was well established. They had a greater biomass production potential and produced 11 cocoons and 22 young ones per 100g of compost in 41 days, Eudrilluseugeniae reduced the time required for composting and increased the rate of degradation and degree of humification. Eudrillus composts had a reduced oxidisable organic carbon content and increased humic acid and alkali soluble carbon content. HA : FA ratio was increased in Eudrillus compost and C:N ratio was narrowed down to a greater extent. Carbon content of humic acid and fulvic acid fractions of the three composts were found to be had comparable values. Vermicomposts showed a pH ranging from neutral to alkaline. Eudrillus compost showed a higher percentage of N, P, K, Mg, Mn, Zn and Cu in them. But Ca content was more in local earthworm compost. Inoculation of beneficial micro organisms increased nutrient levels of vermicomposts to a greater extent. Inoculation of both Azospirillum and P solubilising organisms along with one per cent rock phosphate gave maximum N, P, K and micro nutrients. Ca and Mg were highest in composts treated with P solubilising micro – organisms and one per cent rock phosphate. Various growth parameters were increased due to the application of Eudrillus compost enriched with both Azospirillumand P solubilising organisms. Application of Eudrillus compost increased the uptake of nutrients by plants. Uptake of N, P, Mg, Mn, Zn and Cu were higher for plants treated with Eudrillus compost enriched with both Azospirillum and P solubilising organisms. Yield was maximum for plants treated with Eudrillus compost enriched with both Azospirillum and P solubilising organisms. Yield and nutrient uptake of plants were significantly and positively correlated with nutrient content of compost and so vermitechnology using earthworms as biological agents is found to be the best for bio-degradation of organic wastes. Also Eudrilluseugeniae was found to be the superb effective agent for the operation of this technology.ThesisItem Open Access Dynamics of nutrient release and transformations from slow release fertilizers in acid rice soils(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1995) Nisha, P T; KAU; Sushama, P KA study was conducted to assess the pattern of release and transformation of major plant nutrients from slow release nitrogen fertilisers (SLNF) and to evaluate the efficiency of SLNF at the College of Horticulture, Vellanikkara, during 1992 – 94. Urea formaldehyde (UF), NP tablet (NP tab), NPK tablet (NPK tab), gypsum coated urea (GCU), blended urea ammonium sulphate (UAS) and magnesium ammonium phosphate (MAP) were compared with no (NF) and recommended dose of fertilisers (C). Evaluations were conducted with four acid soils viz., laterite, kari, Kuttanad alluvium and costal sandy kept under incubation for six months and a pot culture study using laterite soil and rice variety Jyothi during puncha season. The release of ammoniacal nitrogen (NH4 – N) was found maximum in kari soil, followed by kuttanad alluvium and laterite and the lowest in sandy soil. Release of nitrate nitrogen (NO3 – N) was maximum in the earlier periods in the case of sandy and laterite soils with lower release at later stages. In the case of kari and Kuttanad alluvium the trend was opposite with higher release at later intervals and lower release at early periods. In general nitrification was found to be low in all the soils. Irrespective of the soil types, the maximum content of NH4 – N was recorded by the NPK tab which was closely followed by MAP, whereas the maximum NO3 – N was registered by MAP. For these two different forms of nitrogen, the minimum values were always found in the NF treatment. The available P content of the soil recorded significant variation throughout the period incubation. Among the treatments MAP and UAS recorded the maximum values and NPK tab the minimum P content. Irrespective of the soil types, there was uniformity in the release of available K throughout the incubation period. In pot culture trial NH4 – N decreased as crop stages advanced. With NO3 – N, an initial decrease followed by an increase at harvest stage was noticed. The treatment GCU recorded maximum NH4 – N and NO3 – N content, while NF the minimum. There was decrease in available P and K contents of the soil as the crop growth proceeded. Significant influence on morphological observations were also recorded with MAP maintaining superiority over other treatments. Maximum dry matter, straw and grain yield were recorded respectively by the treatments UAS, C and MAP. Uptake of N, P and K were also influenced significantly with MAP registering the highest and NF the lowest values. Both NP and NPK tab recorded lower values. Maximum leaching loss of N and P were seen with the control and the minimum with MAP whereas it was respectively with UF and NPK tab for K. The total N recovery percentage, was recorded in the decreasing order : MAP > C > UF > GCU > UAS > NP tab > NPK tab. There was a decreasing order of MAP > UAS > UF > GCU > C > NPK tab NP tab for N response of different treatments under study.ThesisItem Open Access Partial substitution of muriate of potash by common salt for cassava (Manihot esculenta crantz) in oxisols of Kerala(Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani, 1995) Sudharmai Devi, C R; KAU; Padmaja, PField experiments were carried out in the College of Agriculture, Vellayani during 1991 to 1994 to study the possibility and extent of substitution of K of Muriate of Potash with the Na of common salt in Cassava variety M4 used as the test crop. Substitution of K was tried at 4 levels viz. 25, 50, 75 and 100 per cent of the recommended dose. Muriate of potash, replaced by wood ash and a combination of KHCO3 and NaHCO3 (eliminating chlorine source) also were included in the experiment. Plant growth characteristics like plant height and number of leaves did not vary significantly as a result of substitution. The maximum LAI was observed in the case of 50% K as MOP + 50% Na as CS treatment at all the growth stages. An increase in chlorophyll content was observed with NaCl substitution. In the early growth stages there was no significant variation in the production of roots, but at the later stages there was significant difference in this aspect. The root volume at 2 MAP varied significantly between treatments. In general, there was an increase in total weight of plant with NaCI substitution upto 50% and thereafter a decrease with higher levels of substitution, at all growth stages. Significant treatment difference could be observed in tuber yield in both the years of the experiment. T3 (50% MOP +50% CS) registered the highest tuber yield and T5 the lowest. The bulking rate and Utilisation Index also differed significantly among treatments. The cooking quality of the tubers from T3 was as good as that of T1. Significant differences could be observed in total sugars, reducing sugars and sucrose content of fresh tubers under different treatments. With increasing levels of substitution, the content of total sugars increased. Sucrose content was found to increase with Na application upto 75% substitution of K by Na. Significant variation was observed in the crude protein, total amino acid and free amino acid content of tubers. Hydrocyanic acid, total phenols and crude fibre also differed significantly between treatments. The keeping quality studies revealed that tubers from T3 could be stored fresh up to 35th day in moist soil, whereas tubers from T1 could be stored only upto 12th day, without deterioration. Enzyme studies revealed significant difference in the activity of starch synthesising enzymes, but NRA at 6 MAP was not affected by different treatments. The uptake of N was highest in T1 and P and K in T3. Na uptake by T1 which received no Na was generally higher than other treatments receiving Na. Ca and Mg uptake also differed significantly between treatments. Changes in soil organic carbon, available P, available K and available Mg were statistically significant between treatments but that of Ca was significant only from 4 MAP onwards. Yield of tubers was positively and significantly correlated to the uptake of N, P, K, Na, Ca and Mg. Yield at harvest was positively and significantly correlated to the root weight and root volume and also to the bulking rate at 2 MAP. Path coefficient Analysis revealed that the maximum direct effect on yield was contributed by the drymatter of roots at 2 MAP. From the results, it can be concluded that in soils having low to medium status of K, the K of MOP can be substituted up to 50% by Na of commonsalt in cassava without affecting the quality and quantity of tubers.ThesisItem Open Access Evaluation of acidity parameters in wetland soils of Kerala in relation to nutrient availability(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 1995) Usha, P B; KAU; Thomas, Varghese (Guide)Soil acidity is a major constraint in the wetland rice soils of the tropics, which has got aggravated in recent times with the introduction of high yielding varieties of rice and intensive use of fertilizers. Kerala State, with its unique geomorphology, climate, hydrology and other environmental factors has led to the formation of wetland soils with specific physico-chemical and mineralogical properties. These soils sustain a major part of the rice tracts in the State. Attempts to bring these lands under rice cultivation brought to light the intensity and severity of soil acidity in the natural as well as manmade wetlands of this region. Though studies have started way back in 1920 to tackle the problem of acidity and associated nutritional factors, a detailed study to unveil the intricate physico- chemical phenomena contributing to acidity and an economic and efficient methodology to alleviate the severity of acidity has not been attempted so far. Hence a study has been conducted to evaluate the acidity parameters in relation to nutrient availability in wetland rice soils of Kerala. Twelve major wetland rice soils have been identified and classified according to Soil Taxonomy. They belong to natural as well as manmade wetlands, some of them having been indigenously classified and known by vernacular names like Kari land (acid peat), Karapadam (riverine alluvium), Kayal land (lake bed sediments), Pokkali lands (saline acid), Kole lands (flood plain), Kaipad lands (saline marsh). Twelve profile samples representing the major wetland rice soils comprising an area of 6 lakh ha have been subjected to detailed investigations for morphological, physical, chemical, mineralogical and electro chemical parameters. Surface samples, each at a radial distance of 5 km from the twelve locations were collected and subjected to detailed studies to evaluate the acidity parameters and acidity generating factors. Studies were also taken up to observe the kinetics of pH and nutrient availability under submergence for different intervals of time. A comparative study on the efficacy of different methods of estimating the lime requirement was also taken up. From the detailed investigations on the evaluation of acidity parameters of wetland rice soils of Kerala, it has been observed that there exists a great extent of variation with respect to the severity of acitive acidity in the profile and surface samples. Barring Chittoor soils which were slightly alkaline, all the soils under study were acidic in reaction. The profile and surface samples of Kari soil of Thakazhi and Pokkali soil of Njarakkal recorded the highest active acidity with a dry soil pH around 3.2. The rating of these surface soils on the basis of active acidity was Kari ≥ Pokkali > Karapadom > Vellayani > Kayal > Kole > Wyanad > Pattabi > Kaipad > Karamana > Kattampally. However, with respect to the mean values of pH of profile samples the rating was Kari > Pokkali > Kole > Kayal > Karapadom > Vellayani > Wyanad > Pattambi > Karamana > Kattampally > Kaipad. All the soils having high active acidity recorded high exchange, non-exchange and potential acidity with significant correlation between them. It was observed that major part of potential acidity of wetland soils of Kerala was constituted by non-exchange acidity due to the preponderance of Kaolinite clay minerals and high content of sesquioxides. Highest values for potential acidity were recorded by 18-30 cm. of Kari and surface layers of Pokkali profiles. Based on mean potential acidity of surface samples the soils could be rated as Kari > Pokkali > Kayal > Karapadom > Kole > Pattambi > Kattampally > Vellayani > Kaipad > Karamana > Wyanad. HOWEVER, WITH RESPECT TO PROFILE SAMPLES THE SEQUENCE WAS Kari > Pokkali > Kayal > Karapadom > Kole > Wyanad > Vellayani > Kattampally > Pattambi > Kaipad > Karamana. From the correlations worked out, it was found that aqueous pH (1:1) under dry condition was a more reliable parameter for evaluating acidity in the wetland rice soils of Kerala than pH under wet condition or in salt solution, because this parameter gave more significant correlations with acidity generating factors and available nutrients. It was also observed that available sulphur determined both active and potential acidity rather than total sulphur in sulphur rich soils. Path coefficient analysis of acidity contributing factors indicated that exchangeable aluminium was the best parameter for measurement of acidity, 87 per cent of variation in exchange acidity, 57 per cent of variation in non- exchange acidity and 63 per cent of variation in potential acidity. Comparison of different methods for calculating lime requirement proved the superiority of exchangeable aluminium method for the wetland rice soils of Kerala. Lower rates of lime requirement were observed by this method for Kattampally, Wyanad, Karamana, Pattambi and Kaipad soils. Studies on submergence showed that wetland rice soils of Vellayani, Karamana, Karapadom, Kole, Kaipad, Kattampally and Wyanad do not require lime to raise the Ph for rice cultivation because all these soils attain a pH value of 5.5 within two weeks of submergence. Consequently there was increased availability of nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese and silica. However, zinc, copper and sulphur were found to decrease by prolonged submergence. The detailed investigations conducted under this study on the evaluation of acidity parameters of wetland rice soils of Kerala in relation to nutrient availability have unveiled many intricate phenomena of soil acidity which are of great theoretical and practical significance. Contrary to the conventional concept that liming is a must in all acid soils, the present study underlines the cheap and easy method of alleviating acidity of certain wetland rice soils by optimum submergence and scientific water management. Further the study has revealed the feasibility of liming in soils with severe acidity based on specific methods of estimating the lime requirement of soils. However it is necessary to confirm the results of these in- vitro studies by adequate field studies in specific wetland rice tracts of Kerala State.ThesisItem Open Access Effect of coir pith on physico-chemical and moisture retention properties of selected soil groups of Kerala(Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 1995) Venugopal, R; KAU; Sushama, P KAn investigation on the effect of coir pith on physico- chemical and moisture retention properties of selected soil groups of Kerala was carried out at the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, Thrissur during the period 1991-93. Three major soil groups selected for the experiment were coastal sandy, laterite and red. Pots were filled with these soils at the rate of 10 kg soil per pot. Coir pith at the rate of 5 t ha -1, 10 t ha-1, and 20 t ha-1, was added in the soil. An absolute control treatment with no coir pith application and a control treatment with farm yard manure applied at the rate of 5 t ha-1 were maintained. One set of pots was used for incubation study for a period of one year. The soils were maintained at field capacity. Samples were collected from the pots at quarterly intervals and analysis was done for various physico- chemical properties like volume – mass relationships, moisture retention at tensions of 30, 500, 1000 and 1500 kPa and organic carbon. At the end of one year after incubation water stable aggregates and cation exchange capacity were analysed. Another set of pots was used for in vitro study. Cocoa (Theobroma cacao L.) seedlings were raised in the pots. Irrigation was given as and when the plant showed temporary wilting symptoms and the interval between the consecutive irrigations was noticed for different treatments. At the end of the sixth month the plants were taken out and analysed for nitrogen, phosphorus and potassium and uptake of these nutrients were calculated. Soil samples were also collected from the pots to study the available nitrogen, phosphorus and potassium contents. It was noticed that the application of coir pith significantly improved the bulk density, maximum water holding capacity and per cent pore space. There was a significant increase in the moisture retention at different tensions. Water stable aggregates were measured and per cent aggregate stability, mean weight diameter, structural coefficient and stability index showed significant increase with the increasing levels of coir pith. Soil moisture retention at different tensions was significantly influenced by the addition of coir pith. As the level of coir pith increased soil moisture retention increased. Organic carbon content showed an initial increase to a period of six months and subsequently decreased. Cation exchange capacity showed an increasing tendency with increasing levels of coir pith. Significant correlation was obtained between various physical properties and organic carbon content of the soils. After the removal of the crop the available nitrogen content of the soil decreased with increasing levels of coir pith whereas available phosphorus and potassium contents increased with increasing levels of coir pith.ThesisItem Open Access Fertility investigations and taxonomy of the soils of regional agricultural research station, Pattambi(Department of soil science and agricultural chemistry, College of Horticulture, Vellanikkara, 1995) Deepa, K P; KAU; Chinnamma, N PThe Regional Agricultural Research Station, Pattambi has entered it seventh decade of activities. The total area of the station is 63.64 ha and it includes both upland and low land. A detailed survey of the soil in the area of the station has not been made by the Soil Survey Department and hence a taxonomic classification of the soil and fixing of the soil serious as per the soil taxonomy has not been done so far. Therefore the present study was formulated to find out of the morphological and Physico-chemical characteristics of soil profiles of selected blocks, to analyse the surface soil samples from all the blocks for fertility parameters, to classify the soils under taxonomy and to prepare the soil fertility map of the station. The soils had predominantly red hues. Good structural development was noticed in all soils except in ill drained areas. Coarse fragments formed a predominant part in the soil samples collected. In general the soils were acidic in nature. Organic carbon content was low irrespective of crops grown. The nitrogen content of all soils were also low. No regular pattern of distribution with depth was obtained for total reserves of N, P2 O5, K2 O, CaO, MgO and Na2O which were low. Total Fe2 O3 content was fairly high. The cation exchange capacity calculated by NH4 OAC method was low for all the soils. Among the exchangeable bases, Ca formed the predominant cation. With regard to the available nutrient content of soils, nitrogen status of the soul worked out based on the organic carbon content showed that it was high in C block, low in blocks I and IX and medium in the remaining 19 blocks. Nutrient index worked out for available P content showed that it was medium in 12 blocks i.e., E, M, K, I, II, III, IV, V, VI, VII, IX, X and high in the remaining 10 blocks. For available K, the nutrient index values indicated that it was low in 10 blocks and medium in 12 blocks. Based on the nutrient indices, the fertility map of the station was prepared. Based on the profile soil sample analysis, classification of the soils under soil Taxonomy was attempted upto the subgroup level. Among the nine profiles, only 3 i.e., F, I and V fell under Inceptisols and the remaining 6 i.e., F, I and V fell under Inceptisols and the remaining 6 i.e., B, C, I, VIII, IX and X were under Entisols.
