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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 Characterization and evaluation of on-farm liquid organic manures on soil health and crop nutrition(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2017) Sreya, U Parvathi; KAU; Ushakumari, KThe experiment entitled “Characterization and evaluation of on-farm liquid organic manures on soil health and crop nutrition” was undertaken at College of Agriculture, Vellayani during 2014-2017.The study was envisaged to characterize the on-farm liquid organic manures viz., cow urine, panchagavya, fish amino acid, vermiwash and jeevamrutha, to monitor the nutrient release pattern under laboratory conditions and to evaluate the efficacy of soil and foliar applications of these liquid manures on soil health and crop nutrition using bhindi as test crop. The study consisted of three parts. The first part comprised the preparation and characterization of above said on-farm liquid organic manures. These manures were prepared as per standard procedures and characterization study was conducted to determine the physical, chemical, biological and biochemical properties. Physical properties viz., colour and odour of different on-farm liquid organic manures were recorded. Among the liquid organic manures studied, fish amino acid and panchagavya showed acidic pH and other three liquid organic manures viz., cow urine, jeevamrutha and vermiwash recorded neutral pH. Regarding EC, jeevamrutha recorded the lowest value (1.53 dSm-1).The highest OC content (39.96%) was recorded by fish amino acid followed by panchagavya. Among the major nutrients, the highest N content (0.45%) was found in panchgavya followed by fish amino acid. The highest P content was recorded by FAA (0.41%). Maximum K content (0.17%) was recorded in cow urine followed by panchagavya, vermiwash and jeevamrutha. S content of all the liquid organic manures were higher compared to Ca and Mg content. The highest contents of Ca, Mg and S were recorded by fish amino acid. The Fe content (39.92mg L-1) was highest in jeevamrutha and the lowest in fish amino acid. Cow urine was found to be rich in Mn (0.400 mg L-1) and Cu (21.21 mg L-1).The maximum zinc content (2.00 mg L-1), IAA (6.00μg ml-1) and GA (35.00μg ml-1) were found in fish amino acid. Panchagavya was rich in cytokinin (2.82 mg L-1) whereas, ascorbic acid content (37.50 mg 100g-1) was the highest in vermiwash. Fish amino acid was registered the highest enzyme activities, except for dehydrogenase activity which was found to be maximum in cow urine (371.27 μg of TPF g -1soil 24 h-1) followed by fish amino acid (336.98 μg of TPF g -1soil 24 h-1). The maximum population of bacteria was observed in vermiwash and fungal population was presented in all liquid organic manures except cow urine. The highest azotobacter population was observed in fish amino acid. K solubilizers were found to be the highest in vermiwash whereas E.coli, P solubilizers, azospirillum and Pseudomonas sp. were not detected in any of the above liquid organic manures. The second part of the experiment was laboratory incubation study to monitor the nutrient release pattern from soil treated with the on-farm liquid organic manures for a period of two months. The study consisted of 6 treatments which included soil alone and soil treated with 10 per cent dilution of all the liquid organic manures separately and all the treatments were maintained at 60 per cent moisture level. In general increased pH and EC values were observed in all the treatments received diluted liquid organic manures compared to control. Regarding the release of major, secondary and micronutrients, there was significant difference in available nutrient contents between treatments during the periods of incubation. Regarding the release of N and P during incubation study, soil along with FAA 10 per cent recorded the highest release pattern whereas soil along with cow urine 10 per cent recorded the highest K release throughout the incubation period. There was increased release of Ca in the treatments received liquid organic manures. The highest Mg release throughout the incubation period was registered by the treatment received cow urine 10 per cent. Available iron content was higher in T5 (soil 5 kg + jeevamrutha 10 %) compared to other treatments. A significant difference was found among treatments with respect to available Zn content. Initially (0th day of incubation), all the treatments were recorded higher values compared to values recorded on 7th ,15th ,30th , 45th and 60th days of incubation. There was increasing trends in the Cu content of soil from 0th day of incubation to 60th day of incubation except in the case of T3 (soil 5 kg + FAA 10 %). Treatment T1 (soil without treatments) recorded the lowest values for all nutrients throughout the incubation period. The third part of the experiment was to evaluate the efficacy of soil and foliar applications of on-farm liquid organic manures in a pot culture experiment using bhindi as test crop. The treatments included were 75 per cent N as enriched vermicompost along with diluted liquid organic manures separately as soil and foliar applications. Plant height, LAI, dry matter production, number of flowers, number of fruits per plant and total fruit yield were found to be the highest in T5 (75 % N as EVC + panchagavya 3 % foliar application). Chlorophyll a, b and total chlorophyll content were the highest in T10 (75 % N as EVC + jeevamrutha 10 % soil application). T1 (KAU PoP) recorded the highest average fruit weight. T4 (75 % N as EVC + FAA 5 % soil application). registered the highest crude protein content while crude fibre content was lowest in T7 (75 % N as EVC + cow urine 10 % foliar spray). Ascorbic acid content was the highest in T5 (75 % N as EVC + panchagavya 3 % foliar spray) and was on par with T7, T2,T9 and T11. The results of the post harvest analysis of soil revealed that pH, EC, organic carbon and labile carbon contents varied significantly among the treatments. The highest organic carbon content of soil was recorded by T4 (75 % N as EVC + FAA 3 % soil application) and T12 (75% N as EVC + vermiwash 10 % soil application). The maximum labile carbon was recorded by T8. T5 (75 % N as EVC + panchagavya 3 % foliar spray) was rich in available N. Soil enzyme activities were influenced by the application of liquid organic manures. The treatment T5 registered the highest plant uptake of major nutrients. The treatment T3 registered the highest plant uptake of secondary nutrients. The highest value of Fe and Zn uptake was noticed in T11.(75 % N as EVC + vermiwash 10 % foliar spray). The highest value of Cu uptake was noticed in T1 (KAU PoP). The highest value of Mn uptake was noticed in T3 (75 % N as EVC + FAA 5 % foliar spray) . The lowest plant uptake of all nutrients were recorded by T13 (Absolute control). Economics of cultivation of bhindi indicated that cost benefit ratio was found higher for treatment T5, 75 per cent N as EVC + panchagavya 3 per cent foliar application (2.83) followed by T7, 75 per cent N as EVC + cow urine 10 per cent foliar spray (2.09). From the above study, it was concluded that the recommended dose of inorganics (KAU PoP) can be substituted with combined application of enriched vermicompost (enriched with azolla 10 %) to get 75 per cent N and foliar application of 3 per cent panchagavya or soil application of 10 per cent cow urine or 5 per cent fish amino acid at 10 days intervals. Soil health, in terms of physical, chemical, biological and biochemical properties of soil was more enhanced in the treatments received soil application of liquid organic manures. Liquid organic manures viz., cow urine, panchagavya, jeevamrutha, fish amino acid and vermiwash were easily preparable in the farmers’ farm, biodegradable, less expensive, eco-friendly and non-hazardous for human health and environment. From the study it was found that above liquid organic manures were very good organic sources for organic farming and sustainable agriculture.ThesisItem Open Access Effect of agrochemicals on biological activity in lateritic soil(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 2018) Nisha Paul; KAU; Durga Devi, K MIn modern agriculture, agrochemicals are frequently used to boost crop production. The use of pesticides is indispensable in various crops and cropping systems, particularly under tropical climatic condition. However erratic application of these chemicals may affect soil health, which in turn change the population and composition of soil microflora and soil fertility. The land use type also play a significant role in controlling the microbial community. Hence, the present study was undertaken at College of Horticulture, Vellanikkara during 2017-2018 so as to determine the impact of three agrochemicals viz. oxyfluorfen, copper oxychloride and chlorpyriphos on the population of soil microflora and dehydrogenase enzyme activity in lateritic soil collected from two land use types. Representative soil samples were collected from two land use types viz., land under cultivated grass, Agronomy farm, College of Horticulture, Vellanikkara (LUT 1) and cocoa plantation, Cocoa Research Center, KAU, Vellanikkara (LUT 2) during August, 2017. The soil samples were analyzed to assess physical, chemical and biological characteristics before starting experiment and the data revealed that soil collected from LUT 2 was more conducive for microbial growth and dehydrogenase activity. Pot culture experiment with cowpea (variety: Bhagyalakshmi) was conducted during March to June, 2018 with fourteen treatments (3 agrochemicals at 2 different doses under each land use types + 2 controls, one each for two land use types) and three replications. Agrochemicals viz., oxyflourfen (OXY) at 0.15 and 0.30 kg ha-1 (herbicide), copper oxychloride (COC) at 0.75 and 1.50 kg ha-1 (fungicide) and chlorpyriphos (CHL) at 0.30 and 0.60 kg ha-1 (insecticide) were selected for the study. Soil samples were analyzed at four intervals viz., 7, 30, 60 and 90 days after agrochemical spraying (DAS) to evaluate the effect of agrochemicals on chemical and biological characteristics of soil. The chemical characteristics of soil viz., pH, electrical conductivity, organic carbon, available N, P, K, Ca, Mg, S and micro nutrients like Fe, Mn, Cu, and Zn followed a decreasing trend towards the harvest in all the treatments under both the land use types. The effect of agrochemical application on chemical characteristics and nutrient availability of the soil was at lower magnitude compared to their influence on biological activity of the soil. The biological characteristics of soil viz. dehydrogenase activity and microbial population (fungi, bacteria and actinomycetes) were higher in soil samples collected from LUT 2 (cocoa plantation) at all the sampling intervals. Soil samples from both the land use types registered reduction in biological activity due to agrochemical application, which was higher at 7 DAS than the other sampling intervals. The extent of reduction in biological activity after application of agrochemicals was comparatively higher in LUT 1 (land under cultivated grass). Higher doses of the pesticides showed greater decline compared to their lower doses. Biological activity increased from 7 to 60 DAS and the extent of reduction with respect to control also became lower. At 90 DAS, a declining trend in the dehydrogenase activity and microbial population (except fungi) was noticed. The adverse effect of agrochemicals on dehydrogenase activity and bacterial population at 7 DAS followed the order: CHL > COC > OXY and OXY > CHL > COC respectively. However at 90 DAS, oxyflourfen exerted minimum adverse effect on soil bacteria. The study revealed that dehydrogenase activity is highly correlated with the population of soil microflora, especially soil bacteria. The adverse effect of agrochemicals on fungal population can be ranked as: COC > OXY > CHL at both 7 and 90 DAS. The percentage inhibition of actinomycetes population at 7 as well as 90 days after agrochemical application was in the order: OXY > COC > CHL. Cowpea yield was not affected by the agrochemical application and land use types. However higher doses of all the agrochemicals under study reduced the number of root nodules in cowpea.ThesisItem Open Access Rhizosphere priming effects of conventional and non conventional organic manures on c and n dynamics(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2018) Geethu jacob; KAU; Sudharmaidevi, C RA study entitled “Rhizosphere priming effects of conventional and non conventional organic manures on C and N dynamics” was conducted from August 2017 to January 2018 at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani. The objective of the study was to compare the priming effects of conventional and non conventional organic manures on rhizospheric processes with special reference to C and N dynamics. The investigation consisted of four parts namely preparation of organic manures, characterization of organic manures, laboratory incubation study and pot culture experiment to find out the rhizosphere priming effects on C and N dynamics. Four different types of organic manures - aerobic compost (AC), microbial compost (MC), vermicompost (VC), and thermo chemical organic fertilizer (TOF) which were prepared from identical source of organic waste and the popular conventional manure Farmyard Manure( FYM) were analysed for their physical, chemical and nutritional properties. Since TOF is recommended for application after fortification, the fortified treatment TOF-F was also included. The incubation study was carried out in laboratory by mixing 2 kg of red soil with 0.02 kg of each AC, MC, VC, TOF, TOF-F and FYM and keeping for 100 days at field capacity. In order to study the priming effects, fodder maize – var. African tall were sown in pots by mixing 5 kg of soil with 0.05 kg of each AC, MC, VC, TOF, TOF-F and FYM and grown for 90D. A no manure control was also kept under both situations and sampling of soil and plants were done at 0, 15, 30, 60 and 90 D. The studies on characterization revealed that all manures had acidic pH range and safe electrical conductivity (EC) .The highest Total organic carbon (TOC) was recorded by TOF. Dissolved organic carbon (DOC) was not detected in any manures. Regarding the nutritional properties TOF-F had the highest content of N, K, Ca, S, Mn, Zn and B whereas P, Cu and Fe content were the highest in VC. In the laboratory incubation study, soil pH in all the treatments, irrespective of the type, recorded a decreasing trend upto 60 days. EC of the soil also increased upto 30 days in case of all treatments and a slight decrease was observed at 90 days. An increase was recorded in the DOC content until the 30th day in all the treatments. A general increase in the TOC content was observed on 15 D in all the treatments except VC and control(C). At the end of experiment the highest TOC was recorded by TOF-F and TOF. A general decrease in N content was observed in all the treatments with time and at the end of experiment TOF-F maintained the highest value but was on par with MC, VC and TOF and significantly different from the rest of the treatments. The effect of treatments on soil mineralisable nitrogen (Nmin) remained significant from 0 to 30 D only where the highest value was recorded by TOF-F at 0 D. A high status of P was observed in all the treatments at all sampling intervals and the highest P content in the experiment was reported by FYM at 90 D. The K content in soil decreased in all the treatments with time except FYM where an increase in status was observed at the end of the experiment. The content of Ca, Mg, Cu and B in soil remained deficient in the different treatments. Significant difference could not be observed for Fe content at 30 D and 60 D and for Cl at any of the stages of sampling. Analysis of microbial population revealed that bacterial number exceeded both fungus and actinomycetes. In the pot culture experiment also soil pH showed a decreasing trend upto 60 D followed by a slight increase at 90 D. The TOC content ranged from 0.29% (C at 90 D) to 4.73% (TOF at 30 D) and the DOC content in the experiment ranged from 0.04 mg kg-1 (C at 90 D) to 20.28 mg kg -1 (FYM at 30 D). The N content in pot ranged from 75.26 kg ha-1(C at 90 D) to 326.14 kg ha-1(TOF – F at 90 D). Significant difference was observed between treatments for soil Nmin at all stages of sampling. The soil P content in the different treatments were high at all the stages. Even after the crop, the status remained high in all the treatments including the control (C). A general decrease in K content was observed in all the pots after experiment. The secondary nutrients except S were found to be deficient irrespective of treatment. Significant difference between treatments was observed in the case of micronutrients with the exception of Cl. Plant C ranged from 40% (C at 30 D) to 85% (TOF – F at 90 D).The highest N content was recorded by the treatment TOF-F and highest P content was registered by the treatment VC at all levels of sampling. The treatment TOF-F recorded the highest K content in plant at 15 and 30D while TOF was found to be superior at 60 and 90 D. Regarding the Ca level in plant, TOF-F had the highest values followed by MC at all levels of sampling. The plants treated with MC were found to be superior in terms of Mg and S content. The effect of treatments on micronutrient levels remained significant in pot culture experiment. The plants treated with TOF-F recorded the highest shoot mass, root mass and dry matter yield followed by plants treated with MC. A significant positive rhizosphere priming effect was evident in the case of C and other plant nutrients. The microbial population was found to be higher in planted soil than non planted soil. It can be concluded that the conventional and nonconventional organic manures behaved similarly in soil, however fortified TOF (TOF-F) and MC were superior in terms of physical, chemical and nutritional properties. A significant positive rhizosphere priming effect was observed in C and N dynamics, irrespective of the method of preparation of organic manures.ThesisItem Open Access Calcium, magnesium and boron nutrition for grow bag cultivation of cabbage (brassica oleracea L. var. capitata)(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2018) Parvathy, P J; KAU; Gladis, RThe investigation entitled “ Calcium, magnesium and boron nutrition for grow bag cultivation of cabbage” was carried out at College of Agriculture, Vellayani during the period from October to December 2017 with the objective to study the effect of soil and foliar application of calcium, magnesium and boron on growth, yield and quality of cabbage cultivated in grow bags. The experiment was laid out in completely randomised design with nine treatments and three replications. The treatments consisted of two levels of calcium (C1 - CaCO3 as per lime requirement as basal, C2 – CaCl2.2H2O @ 1% foliar spray on 15th and 45 th DAP) , two levels of magnesium (M1 –MgSO4.7H2O @ 20 g plant-1 in two equal splits on 15th and 30th DAP, M2 – MgSO4.7H2O @ 1 % foliar spray on 15 th and 45 th DAP) and two levels of boron (B 1 – Na2B4O7. 10 H2O @ 4 g plant-1 in two equal splits on 15 th and 30 th DAP, B2 – Na2B4O7.10 H2O @ 0.5 % foliar spray on 15 th and 45th DAP ). The treatment combinations were T1- control, T2- C1+ M1+ B1, T3 - C1 + M1+ B2, T4 - C1+ M2+ B1, T5- C1+ M2+ B2 , T6 - C2+ M1+ B1, T7 - C2 + M1+ B2 , T8- C2+ M2+ B1 and T9 - C2+ M2+ B2. The study revealed that the treatment (T7) which received calcium and boron as foliar and magnesium as soil application recorded the maximum plant height (37.12 cm), number of leaves per plant (32.66), plant spread (59.21 cm), and leaf area (699.12 cm2) . The number of days to head formation (50.66 DAT) and head maturity (85.33 DAT) were the lowest in T7 which was on par with T9 . The results on available nutrient status of soil revealed that available nitrogen was the highest in T6 (397.22 kg ha -1). The treatments did not significantly influence the available P and K content of soil. With regard to the available calcium in soil the treatment T5 (C1+ M2+ B2) registered the highest value of 452 mg kg-1 which was on par with T2 and T7.The highest available Mg content of 215 mg kg-1 was recorded in T7 (C2 + M1+ B2) which was on par with T5 and T3. Available S was the highest in T7 (11.69 mg kg-1) which was on par with T2, T3 and T6. The highest available boron content of 1.32 mg kg-1 was observed in T6 . The content of N, P, K, Ca, Mg, S, B and Fe in cabbage head and leaf were significantly influenced by different treatments. The treatment T7 recorded the highest N content in leaves (2.28 %) and head (2.21 %). With regard to P and K content T5 recorded the highest value. The highest Ca content of 2.42 % in leaves and 0.99 % in cabbage head were observed in T7. The treatment T5 recorded significantly higher magnesium and boron content in leaves and cabbage head. The highest sulphur content in leaves (0.43%) and head (0.34 %) were obtained in T4. However the effect of treatments on Mn, Zn and Cu content in plant were found to be non significant. With regard to nutrient uptake T7 showed the highest total uptake of N, Ca , Fe and Mn while T5 recorded the highest uptake of P, K, Mg and B . The highest sulphur uptake was observed in T4 . The chlorophyll content in leaf at heading stage was the highest in T9 (5.39 mg g -1) which was on par with T5 (5.29 mg g -1). The treatments significantly influenced the yield and quality parameters of cabbage. T7 recorded the highest fresh weight of plant (1.833 kg) and head yield ( 1.216 kg) which was on par with T9 and T3. The highest B: C ratio (1.82) was registered by the same treatment and was found to be significantly superior. This treatment effect has registered the highest nutrient use efficiency for Ca (42.55) and B (85.66) and for Mg, T9 recorded the highest value (27.81). With regard to the quality parameters, the highest protein content of 1.93 % and vitamin C content of 64.55 mg -1 100 g was recorded in T 7 which was significantly superior to all other treatments. However the treatments did not influence the crude fibre and oxalate content. From the results , it can be concluded that the treatment T7 (foliar application of calcium chloride @ 1% and borax @ 0.5 % on 15th and 45 th DAP and soil application of MgSO4.7H2O @ 20 g plant-1 in two equal splits on 15 th and 30 th DAP) significantly increased plant growth, yield, nutrient content, nutrient uptake and quality of cabbage.ThesisItem Open Access Evaluation of fertigation vis a vis nutrient stick and foliar silicon in oriental pickling melon (cucumis melo var. conomon)(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Padannakkad, 2018) Mubarack, O P; KAU; Suresh, P RThe investigation on "Evaluation of fertigation vis a vis nutrient stick and foliar silicon in oriental pickling melon (Cucumis melo var. conomon )'was undertaken with the objectives to prepare and formulate nutrient stick, to evaluate and compare its effect with fertigation and foliar silicon on growth, yield and nutrient uptake in oriental pickling melon. The investigation was carried out in two parts, formulation of nutrient stick and field experiment at College of Agriculture Padannakkad and Regional Agricultural Research Station, Pilicode during 2016 -18. Nutrient stick is a complete fertilizer composite that is formulated in solid form. It contains ten essential nutrients. The formulation technique was standardized after trying a series of combination by mixing the finely powdered fertilizer materials. The stick was evaluated in laboratory for dissolution pattern and found completely dissolving in water within two days and in soil solution within three weeks. The field experiment was carried out in randomized block design with nine treatments and three replications. The treatment combinations were, KAU POP with conventional irrigation practices (T1), drip irrigation + soil test based nutrient application as per modified KAU POP (T2), drip irrigation + nutrient stick (T3), 75 per cent of NPK as per KAU POP through fertigation + 25 per cent nutrient stick (T4), 50 per cent of NPK as per KAU POP through fertigation + 50 per cent nutrient stick (T5), T2 + potassium silicate spray @ 0.25 per cent (T6), T3 + potassium silicate spray @ 0.25 per cent (T7), T4 + potassium silicate spray @ 0.25 per cent (T8), T5 + potassium silicate spray @ 0.25 per cent (T9) The application of different treatments showed significant improvement in biometric characters, yield and yield attributes of the oriental pickling melon crop. The shortest duration for days to harvest of the crop was recorded (59.6 days) for the treatment combination of 75 per cent of NPK as per KAU POP through fertigation + 25 per cent nutrient applied as stick. More number of fruits per plants and highest total fruit yield per plot were observed in the treatment with drip irrigation + nutrient stick + potassium silicate given as 0.25 per cent foliar spray. Application of 75 per cent of NPK as per KAU POP through fertigation + 25 per cent nutrient stick along with potassium silicate spray at a rate of 0.25 per cent solution showed highest fruit weight and fruit length. The treatments which included application of silicon as foliar spray recorded maximum shelf life of fruits, extending to six months after harvest. The spray of silicon as potassium silicate was given covering the complete foliage of the crop. The effect of treatments on soil nutrient status were studied at 45 DAS and at harvest stage, showed that N, P, K, Ca, Mg, Fe, Mn, Cu and Si status of the soil varied significantly with treatment application, while pH, EC, S, Zn and B content of soil showed no significant variation among the treatments. Highest available nutrients in the soil at 45 DAS and at harvest were recorded with application of 75 per cent of NPK as per KAU POP through fertigation along with 25 per cent nutrient stick. The leaf nutrient concentrations of oriental pickling melon at harvest were also analysed and it was noticed that, there was significant influence with respect to treatments receiving all the ten nutrients as compared to package of practices recommendations alone. The results obtained from this experiment clearly indicate that application of fertilizers through nutrient stick along with foliar silicon was found to be highly effective. In fertigation treatments residual available soil nutrients were higher as compared to fertilizer through nutrient stick, indicating better efficiency of nutrient sticks.ThesisItem Open Access Effect of soil amelioration and supplementary foliar nutrition on rice yield in kuttanad(Department of Soil Science & Agricultural Chemistry, College of Agriculture, Vellayani, 2018) Lekshmi, S; KAU; Mini, VA study on “Effect of soil amelioration and supplementary foliar nutrition on rice yield in Kuttanad” was carried out to evaluate the effect of soil amelioration with rice husk ash in abating iron toxicity and supplementary foliar application of a customized nutrient formulation in increasing rice yield in the low lands of Kuttanad. The overall fertility status of this region indicated that the soil was acidic with high level of P, medium level of available N and K and wide spread deficiency of Ca, Mg, Cu, Zn and B. A customized nutrient formulation with a composition of K (8.9%), Mg (3.2%), Ca (3.7%), Zn (2.1%), Mn (0.23%), B (3.5%) and Cu (0.96%) was developed based on the available nutrient status of the region and crop requirement. This formulation was used for supplementary foliar nutrition @ 5 kg ha-1 as foliar application of 0.5% solution in two splits at maximum tillering and panicle initiation stage.The field experiment was conducted at Rice Research Station, Moncompu (July to November 2017) with nine treatments and the treatments were T1(Recommended dose of fertilizer and lime (RDF) ),T2 (Soil test based RDF and lime (based on pH)),T3 (Soil test based RDF + Rice husk ash(RHA) @ lime in T2),T4 (Soil test based RDF + RHA @ ½ lime in T2),T5 (T1 + foliar spray of 0.5% solution of customized formulation at tillering and panicle initiation stage (FS) ),T6 (T2 + FS),T7 (T3 + FS),T8 (T4 + FS) and T9(50% Soil test based RDF + RHA @ lime in T2 + FS) replicated thrice in RBD using rice variety Uma. Growth and yield of rice increased significantly due to soil amelioration and supplementary foliar nutrition. During the maximum tillering stage, the highest plant height (55.32 cm) was recorded in the treatment T5 and was on par with all other treatments except treatment T9. The treatments did not show a significant influence on number of tillers at maximum tillering and panicle initiation stages. Treatment T7 recorded the highest number of productive tillers (12.36), which was on par with treatments T6, T5, and T3. The treatment T7 recorded the highest value for all the yield attributes and yield such as panicles per m2 (549.62), thousand grain weight (26.6 g), number of filled grains per panicle (136.5), grain yield (6.60 t ha-1) and straw yield (8.34 t ha-1). The highest number of panicles per m2 recorded for the treatment T7 was found to be on par with treatments T5 and T6 while for the thousand grain weight the treatment T7 was on par with treatment T6, T8 and T4. For grain yield treatment T7 was found to be on par with all other treatments except treatment T4 and T9. The results of scoring of iron toxicity using standard evaluation system for rice (IRRI,1996) at maximum tillering stage and panicle initiation stage revealed that during maximum tillering stage, there was no visual symptom on the plants, but during panicle initiation stage, the symptoms were expressed in treatments T1 and T9 and T9 recorded the highest score(3). Soil analysis done at the time of harvest showed that the pH increased from the initial value of 4.35 to the highest value of 5.5 which was recorded for the treatment T7 and was on par with treatments T3,T4,T5,T8 and T9,while the treatments did not have a significant influence on the EC. The treatment T7 recorded the highest organic carbon content (3.06 %). In the case of primary nutrients, for both available N and P treatment T8 recorded the highest value (385.76 kg ha-1 and 25.22 kg ha-1) and for available K (218.4 kg ha-1) it was recorded by treatment T7. For exchangeable Ca and Mg the highest value was recorded for treatment T6 (157.33 mg kg-1) and T 7 (29.86 mg kg-1) respectively which was superior to all other treatments. In the case of available S, the treatment T5 recorded the highest value (21.17 mg kg-1).The results showed that the treatment T7 recorded the lowest available Fe (322.5 mg kg-1) and Mn (3.27 mg kg-1) content during the harvest stage. For available Zn, Cu, B and Si, the treatment T7 recorded the highest value (3.01, 2.73, 0.504 and 36.83 mg kg-1 respectively) and was superior to all the treatments except for Zn where the treatments did not have a significant influence. The results of the plant analysis revealed that the treatment T7 recorded the lowest leaf iron content during the maximum tillering and panicle initiation stage (125 and 141 mg kg-1).In the case of primary nutrients, for N and K content in grain (1.30 and 0.666 %) and straw (0.77 and 2.32 %) the treatment T7 recorded the highest value and the treatment T8 recorded the highest P content in grain (0.196 %) and straw (0.146 %). In the case of Ca, the treatment T6 recorded the highest value for grain and straw (0.38 and 0.64 %), while for Mg (0.114 and 0.346 %), S (0.351 and 0.373 %) and for Si (0.81and 3.98%) the treatment T7 recorded the highest grain and straw content. Treatment T7 recorded the highest micronutrient content in grain and straw for Mn (42.9 and 157.7 mg kg-1), Cu (6.0 and14.2 mg kg-1), Zn (29.3 and 58.4 mg kg-1) and B (12.1 and16.4 mg kg-1) but recorded the lowest value for Fe content in grain and straw (65 and 154.3 mg kg-1) which indicated the influence of rice husk ash in reducing the iron absorption in plant. The treatment T7 recorded the highest value for uptake of all the nutrients expect for Fe uptake in the plant. The study revealed that the treatment T7 recorded the lowest percentage of incidence of leaf roller (4.37) and there was no incidence of major diseases during the crop period. Treatment T7 recorded the highest net income (Rs. 87679/-) and BC ratio (1.82). From the investigation it can be concluded that, treatment T7 (Soil test based RDF + Rice husk ash @ lime (based on pH) + foliar spray of 0.5% solution of customized formulation at tillering and panicle initiation stage) was the best treatment in which the yield increased by 21 per cent compared to RDF and B:C ratio increased from 1.44 to 1.82 . Effect of rice husk ash in ameliorating soil acidity was found to be on par with application of lime based on pH. Use of rice husk ash as soil ameliorant along with soil test based RDF and supplementary foliar nutrition improved rice yield in Kuttanad and reduced the nutritional constraints due to iron toxicity.
