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ThesisItem Open Access Recycling of cashew (Anacardium occidentale L.) leaf litter and cashew apple through vermitechnology(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2016) Indu, V K; KAU; Jayasree Sankar, SThe present study entitled “Recycling of cashew (Anacardium occidentale L.) leaf litter and cashew apple through vermitechnology was undertaken in the Department of Soil Science and Agricultural Chemistry and at Cashew Research Station,Madakkathara during 2012-2014.The objectives were to study the efficacy of different enrichners on the manorial value of vermicompost prepared from cashew leaf litter and cashew apple using compost worm Eisenia foetida, to identify the role of introduced microbes in decreasing compost maturity time and to evaluate enriched vermicompost as a manurial source in the potting mixture for raising cashew grafts. The objectives were achieved through two experiments viz., (1) preparation of enriched vermicompost and (2) adjudging suitability of enriched vermicompost as a component in potting mixture for cashew grafts. Ferro cement tanks of 1m3 dimension, 300 Kg capacity and lined with jute bags were used for producing vermicompost. All the tanks were initially added with basic feed mixture (cashew leaf litter, cashew apple, sawdust and cowdung in 3:3:2:6 ratio on weight basis. Along with the basic feed mixture, different substrates were added according to the treatments. The experiment was carried out in a Completely Randomized Design with three replications with five tanks per replication. Nutrient status of substrates and that of matured compost was recorded initially and after compost maturity. In addition, pH was also recorded before and after composting, pH ranged from 4.5 in cashew leaf litter to 7.6 in cow dungand poultry manure respectively. Organic carbon content varied from 23% in poultry manure to 49% in coconut leaf. C:N ratio was found between 402.5 in sawdust to 22.62 in poultry manure. The biochemical constituents viz, cellulose, phenol, tannin and lignin were highest in cashew leaf litter (45.9, 1.62, 0.62 and 13.4 mg/100 g respectively) as compared to cashew apple. The compost obtained from T9(T1+ glyricidia leaf+ coconut leaf+ poultry manure+ Trichoderma viride + Pleurotus sajarcaju@ 500 mg kg-1 each of substrate+ Bacillus sp @ 2 kg m-3of substrate) on maturity (120 days), recorded a pH of 7.4, OC (28.6%), N (2.9%), C:N ratio (11), P (0.90%), K (2.0%), total Ca and Mg (1834 & 1185 mg kg-1 respectively) which was highest among other treatments. Earthworm population increased from the initial 200 numbers to1935 numbers in T9 as against 972 in T2which contained Eudrilus euginiaeas the facilitating worms. Xv Daily observations on temperature, weekly observations on pH, total microbial count (initial and final stages), days for compost maturity and earth worm count at maturitywere theother important observations studied in the first experiment. Different treatments was found to have significant effect on temperature. It increased in all the treatments with the composting process, reached a peak and then decreased coinciding with maturity or cooling phase. Highest peak was attained for T9 with 32.5OC. pH of compost mixture were also influenced by the treatments. pH value increased in all the treatments with progress in composting and shifted towards a neutral condition. Maximum pH was associated with T9 (7.3). Number of days required for compost maturity was minimum in T9(120Days) whereas it was maximum in T1(135Days) and the count of earthwormpopulation was nearly nine fold in T9whereas it was only six fold in T1. The lowest multiplication level was observed with T2 which contained Eudrilus eugineae as the compost worms. Based on manurial value assessed by high content of major nutrients (2.4%,0.90% and 2.06% NPKrespectively), compost from T9 of experiment I was selected as the best and designated as enriched vermicompost. Its suitability as a component in potting mixture of cashew grafts was assessed in another experiment. The study consisted of four treatments in four replication with five poly bags (25 x 15cm and 300 gauge) per replication in a CRD Design. The scion for grafting was collected from variety ‘Dhana’. Performance of the grafted seedlings was evaluated for a period of three months. Observations included chemical analysis with and without applying vermicompost for OC, available N, P, K,Ca, Mg, Fe, Mn, Zn and Cu.In addition pH was also recorded. Among the four treatments studied,T4 (sand, soil and enriched vermicompost in 1:1:3 ratio) recorded highest nutrient status (2.75, 0.34 and 0.72 g kg-1 of NPK respectively).The number of days for seed germination was minimum in T4 (15) as against 20 days recorded for seed germination for T1. Other biometric observations like plant height (40.37cm), number of leaves (35) and collar girth (5.3cm) were observed maximum in plants grown in T4. Phytotoxicity was not seen in any of the treatments during the three months of evaluation. By employing the epigeic earthworms Eisenia foetida, the enormously available but untreated lignocellulotic solid organic resource, cashew leaf litter and cashew apple, could be effectively converted to nutrient rich vermifertilizer by suitably admering with various organic enrichners. The vermifertilizer thus produced could be efficiently used as a component in the potting mixture for raising cashew plants. Crop performance was the best when the vermifertilizer was mixed at three parts on volume basis with one part each of xvi sand and soil. Based on results vermicomposting could be established as a ecofriendly and ecologically sound method for manure from cashew leaf litter and cashew appleThesisItem Open Access Silicon availability of tropical soils with respect to rice nutrition(Department of Soil Science and Agricultrural Chemistry, College of Horticulture,Vellanikkara, 2016) Arya Lekshmi, v; KAU; Jayasree Sankar, sSilicon (Si) is the second most abundant element in soil. The amount of silicon in soil depends on parent material, soil type, pedogenic process and landscape. In soil solution, Si is present as monosilicic acid which is the only form that the plant can absorb from soil. The productivity of rice is comparatively low in soils of Kerala. As a ̳Si – accumulator‘, rice can benefit from Si nutrition. The application of Si can enhance growth and yield of rice. With this background, studies were conducted to categorize major rice growing soils of Kerala according to plant available silicon and to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. The release of silicon from different soils added with various silicon sources under different water regimes was also monitored. Soil samples were collected from five different locations representing major rice growing regions of Kerala viz., Kuttanad, Kole land, Pokkali, sandy and lateritic to categorize them according to plant available silicon. The available Si ranged from 7.70 mg kg -1 (sandy soil) to 34.91 mg kg -1 (Kole land soil) in the order Kole land > Pokkali > lateritic > Kuttanad > sandy soil. All the soils under study were categorized as low in available Si. The available Si had positive correlation with organic carbon, available N, Ca, Mg, Fe, Mn, Zn, exchangeable K, Ca, Mg and CEC and negative correlation with available boron, AEC and silica-sesquioxide ratio. These soils were subjected to fractionation of silicon. The major fractions of Si were mobile, adsorbed, organic, occluded, amorphous and residual Si. The percentage distribution of fractions of Si in these soils were in the order; residual Si > amorphous Si > occluded Si > organic Si > mobile Si > adsorbed Si. Quantity – intensity relationship of five major rice growing soils at two temperatures viz. 25 0 C and 40 0 C were studied. The highest buffer power was indicated by Kuttanad soil followed by Pokkali and sandy soils at 25 0 C. It clearly indicated that these soils have a higher power to retain Si on solid phase and replenish its concentration in soil solution as and when it is depleted through plant uptake or leaching. The equilibrium Si concentration and the amount of Si adsorbed by each soil were used to test the fitness of data to the adsorption isotherms viz., Langmuir, Freundlich and Temkin. The data obtained from the adsorption experiments fitted into Freundlich and Temkin equations, but not to Langmuir equation at 25 0 C. At 40 0 C no adsorption equations were obtained for any soil.An incubation study was conducted to know the extent of release of Si on addition of different sources of silicon such as rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate in five rice growing soils under submerged water regime (SWR) and field capacity water regime (FCWR). Addition of Si significantly increased the release of available Si in all soils except Kole land soil after a month. Kole land soil showed higher release of available Si after two months. The highest release of available Si was at SWR in case of Kole land and Kuttanad soil, where as Pokkali, sandy and lateritic soils showed more release of available Si at FCWR. Irrespective of soils, treatment with sodium silicate showed higher release of available Si. Total Si showed a decreasing trend over the period of incubation for three months in all the soils. A field experiment was conducted at Agronomic Research Station, Chalakudy to evaluate the efficacy of different sources of silicon including rice straw in wetland rice. Rice husk ash, biodecomposed rice husk, calcium silicate and sodium silicate were used as source of Si along with fertilizers as per package of practice recommendation (NPK alone). The maximum number of panicles per hill, number of spikelets per panicle, thousand grain weights and minimum number of unfilled grains per panicle were recorded in treatment with calcium silicate application. The maximum grain yield of 6.90 t ha -1 was recorded in treatment T 5 (T 2 + Calcium silicate) and significantly superior (fig.54) over all other treatments. This increase in yield may be due to the effect of application of Si on soil fertility, nutrient uptake, and plant growth. The direct effect of Si fertilization on increased number panicle per hill, number of spikelets per panicle, and thousand grain weight and decreased number of unfilled grains per panicle might be the reason for increased grain and straw yield in treatment with calcium silicate. The treatment with POP + sodium silicate showed the highest uptake of Si by grain and straw of rice. The sources of Si had no residual effect on grain and straw yield of succeeding rice crop. In general, sandy soil low in available Si had a high response to applied Si in achieving higher grain yield.ThesisItem Open Access Enzyme Characterization of the acid sulphate soils of Kuttanad(Department of Soil Science and Agricultural Chemistry, college of Agriculture, Vellayani, 2016) Arya Nath V; KAU; Aparna, BRegarding the enzyme status of the acid sulphate soils, the activity of urease was the highest in Thakazhi (L4-75.78 ppm of urea hydrolyzed g-1 soil h-1) in the surface layer. Acid and alkaline phosphatase activities were found to be the highest in Purakkad (L3-57.58 μg pnp released g-1 soil h-1) and Thakazhi series (L4-46.41 μg pnp released g-1 soil h-1) respectively in the surface layers. The highest activity of dehydrogenase was noticed in Thuravur series (L6-115.74 μg of TPF released g-1 soil 24 h-1) in the surface and Kallara series in the subsurface layers (L2-55.39 μg of TPF released g-1 soil 24 h-1). Karappadam and Kayal recorded the values of 145.73 and 114.80 μg of TPF released g-1 soil 24 h-1 for dehydrogenase activity respectively at surface layers. With regard to the microbial population, Thottappalli (L5) recorded the highest total bacterial count and fungal population in both surface and subsurface layers. Thiobacillus spp. recorded the highest population of 9.08 log cfu g-1 of soil at Kallara series (L2) while P solubilizers recorded the highest count at Ambalapuzha series (L1). Thuravur series recorded the highest actinomycetes population in subsurface soils. Micahelis – Menten constant, Km and the maximum velocity Vmax for different enzymes were determined and it was observed that for dehydrogenase Vmax value was found to be the highest in 6th week and for phosphatase only after 12th week of incubation. Thematic maps were prepared based on themes like microflora and enzyme status using GIS (ARC VIEW). Hence the study conclude that, with respect to biological fertility status of the study area, Purakkad recorded the highest enzyme activity number (23.69) at 0-15 cm, while Kallara series recorded the highest enzyme activity number in the subsurface layer and are observed to be biologically sustainable.ThesisItem Open Access Effect of continuous application of rice husk ash (RHA) on inceptisols of palakkad eastern plains(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2016) Rincy, Rose T John; KAU; Jayasree, Sankar SThe study entitled “Effect of continuous application of rice husk ash (RHA) on Inceptisols of Palakkad Eastern plains” was conducted during 2014 - 16 in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara with the objective of finding out the physical and chemical changes of soil resultant to continuous application of RHA and its relationship with performance of coconut palms. Vadavannur region under Inceptisol soil order of Palakkad Eastern plains stands out as a location where RHA (the product obtained on partial oxidation of rice husk, from rice mill, at a temperature around 250 to 400oC) is continuously being applied in the field for three decades along with inorganic nutrients to the coconut palms at the rate of four to five baskets/palm on volume basis. In this study, RHA samples were collected from the rice mills and analyzed for its composition in terms of carbon, macro and micro nutrients and the beneficial element silicon. Further, representative surface soil samples were collected during August -December 2015 from four RHA amended and non- amended locations of the Palakkad Eastern plains (Vadavannur, Muthalamada, Thathamangalam and Mullakkalkolambu) and its physico- chemical properties were determined. The index leaves (14th leaf) of coconut palms were also collected from RHA amended and non-amended locations and biometric characters (length of index leaf, total number of leaflets per index leaf, average length and width of leaflets, number of bunches per palm and average yield) were recorded. Samples of soil and plant were analyzed for different nutrients viz. C, N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, Na and Si. Analysis of RHA revealed that its pH was alkaline (7.5-8.3). Cation exchange capacity of the material ranged from 7.5 to 9.5 cmol(+) kg-1. Chemical constituents included Si (35%), C (7%), N (0.18- 0.27%), P (0.39-0.57%), K (0.35-0.58%), Ca (0.08- 0.1%), Mg (0.09-0.2%) and micronutrients in trace amounts. On comparison of the physical properties of soil in amended and non-amended locations, the aggregate stability, infiltration rate, water holding capacity and porosity were found to be positively influenced by RHA application. The content of total N, total and available P and K and available Si of soils showed significant increase in amended regions. Exchangeable cations and effective cation exchange capacity were also more in the RHA amended regions. The content of total carbon and particulate organic carbon especially that associated with micro-aggregates was high in the amended area as compared to the nonamended area. A significant difference in the biometric observations of index leaves (length of index leaves and total number of leaflets per index leaf) of palms in amended location as against non-amended locations was another noticeable feature. The palms under integrated nutrient management along with RHA yielded more. The average yield per palm was observed as 86 nuts/year. The content of major nutrients, Ca and Si in the index leaves was also recorded high in the RHA amended palms. The farmers of Vadavannur region resorted to RHA application only with an objective to address the issue of environmental nuisance and menace, without attributing any scientific rationale on its value as a soil amendment. The results of the present study indicate the benefit of application of RHA in improving the physical and chemical properties of soil. The alkaline pH of RHA establishes its suitability as an alternative liming material for acid soils to improve the soil fertility and productivity. It is suggested that further studies conducted under designed experimental stipulations for validation of RHA would decipher more precise information on its suitability as a balanced material for soil amendment.ThesisItem Open Access Ion interactions and rice nutrition in acid saline pokkali soils(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2016) Aditya, Mohan; KAU; Sreelatha, A KThe present study entitled ‘Ion interactions and rice nutrition in acid saline Pokkali soils’ has been carried out to assess the ion interactions in acid saline Pokkali soil, to identify the chemical constraints in plant nutrition and emerging deficiencies or toxicities of nutrients in Pokkali soils. For this purpose, soil samples and plant samples were collected from eight Pokkali locations of Kottuvally panchayath and one from RRS, Vyttila. The eight locations included Mundothuruth, Kalappumpadi, Muppathezhukettu, Periyali, Diamond, Kaitharam, Padinjare Kaitharam and Thathapilli. The soil samples were collected during three stages of cultivation namely mound preparation, mound dismantling and harvest. Two growth stages namely maximum tillering and harvest were selected for the collection of plant samples. The soil samples were characterized for physical (soil texture), chemical (pH, EC, CEC, exchangeable cations, ESP, SAR, percent cation saturation, anions, available N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Al and Na) and biological attributes (MBC, DHA and organic carbon) and the plant samples were analyzed for nutrient contents and uptake. The measured attributes were analysed by two- way analysis of variance using statistical package operational statistics. Canonical analysis was done to find out the decisive ions in Pokkali soils. The t-test was carried out to identify the toxicity and deficiency of nutrients in Pokkali soils and rice. The correlation of Net Ionic Equilibrium (NIE) ratios of K, Mg, Cu and Na with various soil parameters were carried out to identify ion interactions in soil. Analysis of variance revealed that, among various measured attributes, pH, EC, redox potential, available nutrients (N, P, K, Ca, Mg, S, Al and Na), anions (chloride, bicarbonate, sulphate and phosphate), exchangeable cations ( Mg, Na, K, Al, Fe and Mn), percent cation saturation (Ca, Mg, Na and K) and dehydrogenase activity varied significantly among the three stages of cultivation. The decisivecations identified in the exchange complex of Pokkali soils were potassium and magnesium, copper and sodium. Sulphate and phosphate were the predominant anions existing in the soil. Step down regression identified ‘potassium’ having predictive ability towards the presence of sulphate ion. Higher concentrations of P, K,Ca, S, Fe, Mn, Zn, Cu, Al and SO42− were observed in the soil. Magnesium was found to be deficient in the available pool of Pokkali soils. . The plant nutrients namely P, K, Ca, Mg, Fe, Mn, Cu, Zn, B and Na were significantly varying among three stages of cultivation. Magnesium was present in higher concentration in plant despite the deficient concentration of magnesium in soil. The variation in Pokkali rice yield (45 per cent) can be mainly accounted for potassium, calcium, zinc and copper content in soil at the mound preparation stage. During the harvest stage, yield was correlated only with available P. Zinc, boron and aluminium were present in toxic concentrations in plant. The NIE ratios K/ [(Ca+ Mg+ Fe+ Mn) 1/2 + (Al) 1/3 ] and Na/ [(Ca+ Mg+ Fe+ Mn) 1/2 + (Al) 1/3 ] showed significant positive correlations only with CEC and sodium. Phosphate showed a strong negative correlation with both the ratios. The other NIE ratio Mg/ [(Ca+ Mg+ Fe+ Mn) + (Al) 2/3 ] showed significant negative correlation with pH and phosphate. The ratio Cu/ [(Ca+ Mg+ Fe+ Mn) 1/2 + (Al) 1/3 ] showed a negative correlation with electrical conductivity, Na and K. The availability of cations namely K, Mg, Cu and Na was significantly influenced by various soil parameters. The present investigation identified high concentrations of micronutrients, Al and B in Pokkali soils, toxic concentrations of Zinc, boron and aluminium in plant and influence of different soil parameters on availability of K, Mg, Cu and Na. The rice yield mainly depended on available K, Ca, Zn, P and Zn contents in soil.ThesisItem Open Access Accumulation of heavy metals in typic sulfaquents of Kuttanad ecosystm(Department of Soil Science and Agricultural Chemistry,College of Horticulture, Vellanikkara, 2016) Aneesa, Beegum M M; KAU; Beena, V IAn investigation entitled “Accumulation of heavy metals in Typic Sulfaquents of Kuttanad ecosystem” was conducted in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Kerala Agricultural University during 2014-2016. Sample collection was done from six acid sulphate soil series of Kuttanad viz., Ambalapuzha, Kallara, Thakazhi, Purakkad, Thottapally and Thuravur series. Twenty soil, sediment and water samples were collected from each series. Dominant aquatic macrophytes were also collected from each series. Mainly three mangrove species (Avicennia officinalis, Bruguiera gymnorrhiza and Rhizophora mucronata) were present in the area, and were collected for analysis. Soil and sediment samples were characterized for texture, pH, EC, organic carbon, macronutrients, micronutrients (Fe, Mn, Zn and Cu) and heavy metals (Pb, Cr, Hg and Al). Water samples were analysed for its irrigation quality parameters such as colour, temperature, turbidity, suspended solids, pH, EC, biological oxygen demand (BOD) and chemical oxygen demand (COD). Also the plant and water samples were analysed for its macronutrients, micronutrients (Fe, Mn, Zn and Cu) and heavy metals (Pb, Cr, Hg and Al). Based on the analytical data, maps were prepared by using specialized software ArcGIS ArcMap version 10 of ESRI. The soil samples from acid sulphate soil series of Kuttanad were extremely acidic whereas the sediment and water samples were slightly acidic. Highest EC values were recorded for soil, sediment and water samples collected from Purakkad series. Significantly higher OC and available N content were observed in soil and sediment samples collected from Kallara series, while the water samples taken from this series showed high ammoniacal N content. The available P content was low in all the series. Soil and sediment samples collected from Thuravur series exhibited highest content of N, P, K, Ca and Mg. In all the series, Cd and Hg were found to be below detectable levels in soil, sediment and water samples. The heavy metal accumulation was more in sediments when compared to soil and water. Toxicity of Fe and Al was recorded in soil and sediment samples of all series. Concentration of Zn and Mn was high in all soil samples of acid sulphate soil series. Even though accumulation of Pb and Cr were reported in soil and sediment samples, their availability were more in sediment samples than in soil samples. Soil pH and OC had significant influence on availability of heavy metals in soil and sediments. Concentration of Fe, Al and Cr in water samples were above the maximum permissible limit (MPL) as suggested by WHO, hence they are not suitable for drinking water purpose. The concentration of Pb was below maximum permissible limit in water samples of all series except Purakkad and Thottapally series. According to FAO, for irrigation water quality, all heavy metals were within the MPL in the water samples collected from study area and were safe for irrigation. Along with Cd and Hg, Zn and Cu were also below detectable levels in all water samples. The heavy metal content in Eichhornia crassipes were in the order of Fe >Mn > Al> Zn> Cr> Cu >Pb. Among the dominant macrophytes, Eichhornia crassipes accumulated high content of Pb. Hence it can be effectively used as a phytoremediator. Salvinia molesta contained high amount of heavy metals, especially Cr and Al. The content of Cd and Hg were below detectable level in all weed species. The content of Zn, Cd and Hg were found to be below detectable levels in all the three mangrove species. But these contained high concentration of Fe, Pb, Cr and Al in roots, while Cu and Mn were accumulated in aerial parts such as shoot and leaves. Hence the three mangrove species viz., Avicennia officinalis, Bruguiera gymnorrhiza and Rhizophora mucronata restricted the mobility of heavy metals to aerial parts but showed greater mobility of essential elements like Cu and Mn. Since they are having extensive root system, they can stabilise heavy metals within the roots. These plants can be effectively used for phytoremediation, especially for phytostabilisation of metals in mangrove ecosystem.ThesisItem Open Access Formulation and evaluation of micronutrient mixture for foliar application in tc banana (Musa sp.) Var. Nendran(Department of Soil Science and Agricultural Chemistry, college of Agriculture, Padannakkad, 2016) Premalatha, A; KAU; Suresh, P RThe experiment entitled “Formulation and evaluation of micronutrient mixture for foliar application in TC banana (Musa sp.) var. Nendran” was carried out with the objectives of preparing a micronutrient mixture formulation for foliar spray, to evaluate stability of formulation and its keeping quality and to investigate the effect of this formulation on growth, yield and quality of fruits in banana (Musa sp.) Nendran. The whole study consisted of three parts – preparation of micronutrient mixture formulation, hardening studies and field experiment. The studies were carried out at College of Agriculture, Padannakkad and RARS farm, Nileshwar during 2014–2016. Micronutrient mixture formulation was prepared with the use of different micronutrient salts containing Zn, B, Fe, Mn, Cu and Mo. The formulation technique was standardized and it was prepared as two liquids: Solution A and Solution B. Solution–A consisted of ZnSO4, CuSO4, FeSO4, H3BO3, MnSO4 and (NH4)2MoO4 in desired proportion. For maintaining stability and keeping quality of solution A, addition of citric acid was found to be the best. Solution B was prepared as 1 per cent humic acid. Required quantity of solution A and B was diluted and blended just before spraying. The hardening studies were conducted in the poly house with TC plants of uniform stage multiplied from same genotype. The experiment was carried out in CRD with 12 treatments and one control with 3 replications each and there were 4 plants in each unit. The treatments consisted of 4 levels of micronutrient mixture (0.25 %, 0.5 %, 0.75 % and 1 %) sprayed at 3 different intervals. The 3 different spray scheduled were: one spray- immediately after planting and 2 subsequent sprays given at 2nd and 3rd weeks after planting during secondary hardening stage. Thus there were 12 treatment combinations and one control. The treatments were: T1, T2, T3 and T4 - one spray, T5, T6, T7 and T8 - two sprays and T9, T10, T11 and T12 - three sprays of 0.25, 0.5, 0.75 and 1 per cent concentrations respectively. T13 was control.ThesisItem Open Access Gypsum as a soil ameliorant for black pepper (Piper nigrum L. ) in acid soils of Wayanad(Department of Soil Science and Agricultural Chemistry , College of Agriculture, Padannakkad, 2016) Aloka, Y G; KAU; Jayaraj, PThe experiment entitled “Gypsum as a soil ameliorant for black pepper (Piper nigrum L.) in acid soils of Wayanad” was carried out with the objectives to study the performance of gypsum as a soil ameliorant in growth and development of black pepper and to evaluate its suitability in promoting root growth into deep soil layers of central plateau of Wayanad. The entire investigation was carried out as three experiments, an incubation experiment at College of Agriculture, Padannakkad and two pot culture studies (Column experiment and Double/dual root experiment) done at KVK, Kannur during 2015- 2016. The soil samples for all three experiments were collected from different soil layers (1 st layer: 0-25 cm, 2 nd layer: 25-50 cm, 3 rd layer: 50-75 cm and 4 th layer: 75-100 cm from top soil surface) of pepper garden of RARS, Ambalavayal. The incubation study was laid out in CRD with 8 treatments, 3 replications each and 3 columns were maintained in each replication, the columns were filled layer wise depicting soil profile. The treatments were T 1 - Ca as gypsum at the rate of 50 per cent of CEC, T 2 - Ca as burnt lime at the rate of 50 per cent of CEC, T 3 - Ca as dolomite at the rate of 50 per cent of CEC, T 4 - Ca as gypsum at the rate of 25 per cent of CEC + burnt lime at the rate of 25 per cent of CEC, T 5 - Ca as gypsum at the rate of 25 per cent of CEC + dolomite at the rate of 25 per cent of CEC, T 6 - Ca as CaCO 3 at the rate of 50 per cent of lime requirement, T 7 - Ca as CaCO 3 at the rate of 100 per cent of lime requirement, T 8 - Control. The results of the experiment revealed that the treatments had a significant influence on available soil nutrient status. Application of gypsum showed increase in pH in the lower soil layers as compared to surface layer. Addition of ameliorants particularly gypsum recorded maximum Ca content in all soil layers as compared to sole application of burnt lime and dolomite. This is attributed to high solubility of gypsum, which permits Ca availability in lower soil layers also. The exchangeable Al, the major ion contributing to surface and subsurface acidity in lateritic soils was found minimum with addition of all soil ameliorants amongwhich the maximum reduction was observed with respect to gypsum treatments. The soil available N, P 2 O 5 , K 2 O contents also showed higher values in all surface and subsurface soil layers in gypsum ameliorated soil columns. The column experiment was conducted with 8 treatments and 3 replication under the design CRD at KVK, Kannur. The black pepper var. Panniyur -1 was planted in each column and the treatments imposed were gypsum at different levels in 5 treatments, Ca as gypsum at the rate of 10, 20, 30, 40 and 50 per cent of CEC (T 1 to T 5 ) and Ca as CaCO 3 in two treatments at the rate 50 and 100 per cent of lime requirement (T 6 and T 7 ) along with one control (T 8 ). The results obtained with respect to biometric observations revealed that T 4 (Ca as gypsum at the rate of 40% of CEC) showed maximum plant height, number of leaves, internodal length, fresh and dry root weight at all the stages of plant growth and was on par with T 5 (Ca as gypsum at the rate of 50% of CEC). The root length was maximum in T 4 at 60 and 120 DAP and later at in 180 DAP T 5 recorded highest root length and was on par with T 4 . The soil analysis of column experiment revealed that the treatments T 5 and T 4 significantly increased soil pH, available N, P 2 O 5 , K 2 O, Ca, S and significantly decreased exchangeable Al due to increased solubility and leaching of gypsum in all four soil layers, hence treatments T 4 and T 5 showed superior plant growth and root proliferation at various stages of plant growth. T 4 and T 5 also recorded highest total N, P, K, Ca, S and lowest total Al accumulation in leaf samples in all stages of plant analysis. The second pot culture study with double root experiment was conducted at KVK, Kannur with similar treatments as in incubation experiment with var. Panniyur -1. The ameliorants were added into one root column in which the sprout emerged. The results with respect to biometric observations differed significantly at different growth stages. The treatment T 5 (Ca as gypsum at the rate of 25 per cent of CEC + dolomite at the rate of 25 per cent of CEC) recorded maximum plant height and number of leaves.The observation on root growth recorded at 60, 120 and 180 DAP differed significantly in both ameliorant treated and the dual untreated columns. In treated columns the treatment T 4 (Ca as gypsum at the rate of 25 per cent of CEC + burnt lime at the rate of 25 per cent of CEC) recorded significantly superior dry root weight at 60, 120 and 180 DAP and fresh root weight at 60 DAP. The treatment T 5 recorded maximum fresh root weight at 120 and 180 DAP. In the case of untreated root columns at 60 DAP T 4 had significant maximum dry root weight, where T 5 had maximum significant effect on fresh root weight. The fresh and dry root weight was significantly influenced by T 6 at 120 and 180 DAP. The root length also showed significance difference, in both treated and untreated columns treatment T 4 at 60 DAP and T 5 at 120 and 180 DAP recorded maximum root length. The soil analysis of double root experiment shows that the gypsum treated (T 1 , T 4 and T 5 ) soils were significantly superior to CaCO 3 and control treatments. The sole gypsum and gypsum in combination with burnt lime and dolomite treated soils showed increased soil pH, available nutrient content and decreased exchangeable Al in all the four soil depths and at each interval of soil analysis. The plant analysis carried out at 60, 120 and 180 DAP showed significance difference, among treatments T 5 and T 4 recorded highest total N, P, K, Ca and S content, where T 4 recorded lowest exchangeable Al and was on par with T 5 . The results of investigation indicated that application of gypsum as an amendment alone or in combination with burnt lime and dolomite reduced the surface and subsurface acidity and increased the available nutrient status in the surface as well as sub surface soil layers, which might have resulted in better root proliferation favouring vigorous plant growth and development of black pepper in acid soils.ThesisItem Open Access Absorption and translocation of 32P by root (wilt) affected coconut palms(College of Horticulture, Vellanikkara, 2016) Beena, S George; KAU; Moossa, P PAn investigation entitled “Absorption and translocation of 32P by root (wilt) affected coconut palms” was conducted in the Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara. Two separate experiments were conducted in farmers’ fields at Mannarkkad, Chittur, Chavakkad, Kayamkulam and RARS, Pattambi. Three types of palms namely healthy, apparently healthy and diseased palms were identified from three soil types of Kerala (laterite, sandy and black cotton soil), where root (wilt) disease was prevalent. Four morphologically uniform palms of same age were selected from each group of palms and soil samples were collected from two depths; 0-20 cm and 20-40 cm from the basin. Index leaf samples (14th leaf) were also collected from the experimental palms. Soil samples were characterized for different physico-chemical properties and plant samples for N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Cl and Na. Absorption and translocation of nutrients in coconut palm were studied using radioactive phosphorus in laterite soil. Before 32P application, in order to make homogeneous soil conditions, soil and plant samples were analysed and soil test based fertilizer combinations including organic manures and micronutrients were applied. Three months after fertilizer application, soil and plant samples were again collected and analysed. Three different methods (cotton pad technique, root feeding and soil injection) were employed for 32P application. The index leaf samples were collected at 24 hours, 15 and 30 days after application and radioassayed. The result of basic characterisation of soil showed that all the physico-chemical properties varied significantly among different soil types. Laterite soil recorded the highest value for available P, K, Fe, Mn, Cu and B. High values of EC, Cl, Na and AEC were obtained for sandy soil. Black cotton soil registered the highest values for pH, organic carbon, Ca, Mg, S, Zn and CEC. Among soils under different palms within same soil type, there was significant variation in the content of Mg, B, Zn and Cu. Among different palms K accumulated more in the foliage of diseased palms, while the concentrations of N, Ca, Mg, Fe, Mn, Zn, Cu and B were more in the foliage of healthy palms, indicating nutritional imbalance in the root (wilt) affected palms. Before application of fertilizer in laterite soil, the contents of nutrients were not homogeneous among soils under different palms. After fertilizer application, the soil became more or less similar with respect to the nutrient content. The contents of N, Ca, Mg, Fe, Mn, Zn and Cu were significantly more in the foliage of healthy palms and K was more in the foliage of diseased palms before fertilization. Even after application of fertilizer same trend was observed. Though there was a slight increase in nutrient status of diseased palms after fertilizer application, the rate of increase was comparatively less with respect to healthy palms. This showed that integrated nutrient management targeting soil application cannot fully manage the root (wilt) disease. In absorption and translocation studies using 32P, it was observed that the absorption of radioactive phosphorus was more for healthy palms compared to diseased palms, after 24 hours, 15 days and 30 days of application. For healthy palms, the count rate was more for root feeding method, while in diseased palms highest count rate was obtained by using cotton pad technique. The count rate in the foliage after 15 days was more when compared to 24 hours after application and it tended to decrease 30 days after application. Nutrient imbalance was one of the major problems noticed in root (wilt) affected palms, so it should be corrected first by proper method of application. Among the different methods tested, cotton pad technique can be a promising technique of delivery of nutrient into root wilt affected palms especially for micro nutrients, which needs less quantity compared to major nutrients.
