Loading...
Theses
Browse
36 results
Search Results
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 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 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.ThesisItem Open Access Effect of phosphorus solubilisers on the availability of native P in phosphorus rich soil(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2018) Sreelakshmi, M M; KAU; Aparna, BThe present study entitled "Effect of phosphorus solubilizers on the availability of native P in phosphorus rich soil" ‖ was carried out in the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani during 2017-’18. The study was envisaged to evaluate the effect of phosphate solubilizers on the solubility and availability of native phosphorus and its impact on crop growth and yield of test crop tomato var. Vellayani Vijai. The experiment was laid out in a randomized block design with fourteen treatments and three replications viz. KAU POP (T1), 75% P + PSB (T2), 75% P +AMF (T3), 75% P + Psuedomonas fluorscences (T4), 50% P + PSB (T5), 50% P + AMF (T6), 50% P + P. fluorscences (T7), 25% P + PSB (T8), 25% P + AMF (T9), 25% P + P. fluorscences (T10), PSB (T11), AMF (T12), P. fluorscences (T13), Absolute control (T14). From the study, it was observed that a significant increase in soil pH from the initial value of 4.5 was noticed in all the treatments except the control plot. The highest pH value of 5.2 was recorded by the treatment T9 (25% P +AMF). The treatments imposed no significant difference with respect to the electrical conductivity, organic carbon, organic matter and available nitrogen content. However, the treatment T4 (75% P + P. fluorscences) registered the highest value for organic carbon (1.11%) and organic matter content (1.91%) and T6 for available N content (282 kg ha -1). The analysis of the data indicated that available K content in soil was significantly influenced by the application of P solubilisers with the highest value recorded for the treatment T4 (162.33 kg ha-1) . Application of 75% P +AMF (T3) recorded the highest value for available phosphorus (111.52 kg ha -1). It was also, observed from the study that the available P increased to the maximum at 3 months after planting (MAP) and decreased at 4 MAP. The analysis of data on available micro nutrients revealed that the treatments had significant influence on available Zn content with the highest value recorded by T9 (4.67 mg kg-1) whereas the effect was non-significant with respect to available Fe, Mn and Cu content. Exchangeable aluminium and hydrogen content of soil tends to decrease at harvest stage. The treatment T10 registered the lowest values of 0.073 cmol (H+) kg-1 and 0.266 cmol (Al+3) kg-1 for H+ and Al+3 respectively. The analysis of different P fractions revealed that Al-P, Fe-P, occluded P and reductant soluble P decreased over a period of 4 months while Ca-P and saloid P fractions increased. The highest values were recorded by the treatments T13 (182.6 kg ha-1), T6 (123.52 kg ha-1), T9 (41.43 kg ha-1), T14 (45.2 kg ha-1), T14 (32.33 kg ha-1), T3 (8.22 kg ha-1) for Al-P, Fe-P, Ca-P, occluded P, reductant soluble P and saloid P respectively. Studies on enzyme activities and microbial population revealed a positive influence of P solubilisers. Activities of major soil enzymes viz dehydrogenase, urease, acid phosphatase and alkaline phosphatase showed an increased trend and reached the maximum at the final stage of crop growth (harvest stage).The treatments T11 (58.89 μg of p-nitrophenol released g-1 ) and T9 (9.95 μg of p-nitrophenol released g-1) registered highest value for acid phosphatase and alkaline phosphatase activity respectively. The highest value for dehydrogenase and urease were observed in T3 and T6 treatments with mean values of 336.7 μg of TPF released g-1 soil 24 h-1 and 69.45 ppm of urea hydrolysed g-1 of soil 24 h-1 respectively. The highest values for microbial biomass carbon (380 μg g-1 soil) and microbial biomass phosphorus (71.83 μg g-1 soil) were observed in treatments T9 and T5 respectively. With respect to the population P solubilisers (microbial load), the highest value was noticed in treatment T6. Application P fertilizer along with P solubilisers has improved the plant characters like no of primary branches, days to 1st flowering and no of fruits. The treatment T2 registered the highest no of fruits (36 / plant). The treatments did not impose any significant effect on fruit characters like TSS (%) and Vitamin C content. While the highest values for lycopene (12.33 μg g-1) and beta carotene (382.60 IU) were observed in treatments T5 and T2. The highest fruit yield (1.52 kg/plant) and dry matter yield (84.80 g/plant) of test crop, tomato was noticed with the application of treatment T3. This was found to be on par with treatment T4 with an average fruit yield of 1.49 kg/plant yield and dry matter yield of 81.80g/plant. The treatment T3 recorded highest values for P content in fruits (0.67%), shoots and roots (0.45%) and total uptake of P (38.89 kg ha-1). Similarly the highest B: C ratio was recorded in the treatment T3 indicating the superiority of T3 (1.72) over the other treatments. Correlation studies revealed a significant positive correlation between available phosphorus and yield (r= 0.89**), available P and saloid P fraction (r=0.918**), alkaline phosphatase activity and pH (r=0.936**), dehydrogenase and organic carbon (r=0.672**), urease activity and organic carbon (r=0.701**). From the study it was observed that microbial load is positively correlated with acid phosphatase activity (r=0.793**), alkaline phosphatase activity (r=0.545*) and urease activity (r=0.604*). It is evident from the study that treatments T3 (75%+AMF), T4 (75% P + Psuedomonas fluorscences), and T6 (50%+AMF) were superior among the treatments. But considering the available P content, P fractions, plant yield, P uptake and B : C ratio, the treatment T3 (75%+AMF) was considered as the best treatment.ThesisItem Open Access Response of bhindi (abelmoschus esculentus L. moench) to fertigation and foliar nutrition in red loam soil of Kasaragod(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Padannakkad, 2018) Ashwini, B N; KAU; Binitha, N KAn investigation entitled “Response of bhindi (Abelmoschus esculentus L.Moench) to fertigation and foliar nutrition in red loam soil of Kasaragod.” was carried out at College of Agriculture, Padannakkad and Regional Agricultural Research Station (RARS) farm, Nileshwar during 2016 to 2018. The study was conducted in bhindi variety Arka Anamika. The objective of the study was to standardize the time and site specific dose of nutrient application in sub humid red loam soil and evaluate the effect of fertigation of major nutrients along with foliar nutrition of micronutrients on growth, yield and fruit quality of bhindi. The field experiment was laid out in Randomized Block Design (Factorial RBD) with eight treatments and two controls and each were replicated three times. The treatments included combinations of two fertigation intervals (T1-once in two days and T2-once in four days) and two levels of fertigation (L1-100 per cent NPK as per KAU POP and L2- 50 per cent NPK as per KAU POP) along with two levels of foliar application of micronutrient mixture (S1-Micronutrient mixture at the rate of 2 per cent and S2- Micronutrient mixture at the rate of 4 per cent). The treatment combinations were compared with two controls viz., Kerala Agricultural University (KAU) POP with conventional irrigation practices (Control 1) and Kerala Agricultural University (KAU) ad hoc organic POP with conventional irrigation practices (Control 2). The micronutrient mixture consisted of Fe, Mn, Zn, Cu, B and Mo in definite composition had been standardized for foliar application in bhindi. The results of the experiment revealed that the growth parameters, viz., plant height, number of leaves, number of branches and stem diameter at 30, 60 days after sowing (DAS) and at harvest were highest in plots fertigated once in two days interval (T1). The main yield attributes such as the number of flowers,maximum length of fruits, diameter of fruits and fruits per plants was recorded were highest in T1 resulting in maximum fruit weight per plant (362.98 g plant-1) and totalfruit yield (19.70 tha-1). The protein content of fruits (10.69 %), carotenoids (2.72 mg g-1), vitamin C (23.62 mg100 g-1), total chlorophyll content of leaf (9.21 mg g-1) were also maximum, with minimum content of crude fiber (6.23 %) in fertigation interval of two days (T1) compared to fertigation given at four days interval (T2) . Plants receiving fertigation levels at 100 per cent NPK as per KAU POP (L1) resulted in significantly higher growth, yield and yield attributing characters such as the number of fruits per plant (22.85), fruit weight and total fruit yield (22.85 t ha-1) and leaf chlorophyll content. It was also evident that fruit quality parameters such as carotenoids, vitamin C and protein content of bhindi fruit was maximum in treatments receiving fertigation levels at 100 per cent NPK as per KAU POP (L1). This treatment recorded lower values of crude fibre (5.91 %). Foliar application of micronutrients at 4 per cent concentration significantly influenced yield and yield attributing characters like number of fruits per plant, length and diameter of fruit but had no influence on vitamin C and crude fibre content. The two way interaction effects of fertigation intervals, fertigation levels and foliar application of micronutrients were not significant with respect to days to first flowering and days to 50 per cent flowering. However minimum number of days to first flowering (34 days) was noticed in L1. The combined effect of fertigation at 100 per cent NPK at two days interval recorded maximum number of flowers per plant, fruit length, total chlorophyll, carotenoids and vitamin C content. Considering the three way interaction between time of fertigation, levels of fertigation and foliar application of micronutrients had no significant effect on growth, yield attributes and quality parameters of fruits. A comparative evaluation of treatments with the controls revealed that all growth characters, yield attributes and quality parameters were superior in the treatment plots over both the controls. The comparative study between two controls reported that KAU POP with conventional irrigation practices (Control 1) was superior over KAU ad hoc organic POP with conventional irrigation practices (Control 2). The effect of treatments on leaf nutrient concentration at harvest was studied, the results showed that N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B and Mo content were found to be significant in treatments receiving fertigation at two days interval (T1), fertigation levels of 100 per cent NPK and foliar application of micronutrient. Similarly, soil nutrient availability at 60, 90 DAS and at harvest revealed that available nutrient status of N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B and Mo status at all the stages of crop showed significant difference among the treatments. The optimum fertigation level and interval (fertigation of 100 per cent NPK as per KAU POP at two day interval) recorded maximum nutrient content in soil. Highest available nutrients during the cropping period as well at harvest were recorded in treatments as compared to controls, whereas comparison between control 1 and control 2, showed that control 1(KAU POP) registered maximum values of available nutrients in soil. The finding of the present investigation revealed that current nutrient recommendation of KAU POP through fertigation has doubled the yield, when compared with the reported values of state averages of productivity (9.74 t ha-1). The fruit nutritional quality improvements were also noticed.
