1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Integrated nutrient management for ornamentals in vertical garden(Department of Floriculture and Landscaping, College of Agriculture, Vellayani, 2024-04-20) Chanchal Gireesh, S; Priya Kumari,IThe research programme entitled ‘Integrated Nutrient Management for ornamentals in vertical garden was carried out in the Department of Floriculture and Landscaping, College of Agriculture, Vellayani, Thiruvananthapuram during the period 2022-2023 to evaluate the growing media components, biofertilizer, and foliar nutrient spray for improving growth of foliage ornamentals in vertical garden system This study comprises of two objectives the first objective is to standardise the growing media composition and biofertilizer in Nephrolepis cordifolia and the second objective is to standardize the foliar spray for ornmanetal foliage plants such as Chlorophytum comosum, Tradescantia fluminensis, Rheo discolor, Peperomia obtusifolia and Epipremnum aureum The first experiment was “ Standardization of growing media composition and biofertilizer”, laid out in Completely randaomized design with 15 treatments involving 5 different media such as M1-Control (soil + sand + FYM) (1:1:1), M2- (soil + rock sand + coirpith + vermicompost ) ( 1:0.5:0.5:1), M3- (soil+ rock sand + vermicompost )(1:1) + Hydrogel (25g), M4- (coirpith + vermiculite + perlite + vermicompost )(1:0.5:0.5:1) and M5 - (coirpith + newspaper bits + charcoal bits + vermicompost)(1:0.5:0.5:1) and three biofertilizers (B1 – Control (without biofertilizer), B2 – VAM (3g / container ) and B3 – PGPR-1(2g/ container ) for improving growth of foliage ornamental Nephrolepis cordifolia Notably, treatment combination M4B1 comprising coirpith, vermiculite, perlite and vermicompost in the ratio 1:0.5:0.5:1 and biofertilizer , B2 (VAM ) at 3g/ container, exhibited superior performance across various parameters such as plant spread, plant height, number of divisions, leaf number, leaf production interval, total biomass production, chlorophyll content and ornamental value index. Conversely, M3(soil: rocksand : vermicompost) (1:1 ) with the addition of Hydrogel (25 g) demonstrated the least favourable outcomes in terms of plant spread, number of leaves , leaf production interval , total biomass production and ornamental value index . In the second experiment, for “standardization of foliar spray for ornamentals”, the media which was standardized from the first experiment were taken and 5 foliage ornamentals were planted in the prescribed media and foliar fertilizers such as F1 – control – 19:19:19 (1%) @ 25ml/ plant at fortnightly intervals, F2- Complex fertilizer 19:19:19 (1%) monthly, F3 – Urea (1%) monthly and F4 – Complex fertilizer 30:10:10 (1%) monthly were studied Among the interaction effect, treatment combination F3P2 revealed significantly higher value for plant spread and plant height, whereas it was significantly lower in F1P5. For total biomass production and air pollution tolerance index F2P4 showed significantly higher values and it was lower for F4P4. For total chlorophyll content F1P4 was having significantly higher values and lower value was observed in F4P2. Among the various foliage plants studied Peperomia obtusifolia (Baby rubber plant) showed less tolerance to pollution plant spread, plant height and number of branches were found significantly higher for Tradescantia fluminensis (wandering jew) The study concludes that media comprising coirpith, vermiculite, perlite and vermicompost in the ratio (1:0.5:0.5:1) along with biofertilizer, VAM at 3g/ container, exhibited superior performance in Nephrolepis cordifolia under vertical garden system. The same media composition (coirpith, vermiculite, perlite and vermicompost in the ratio 1:0.5:0.5:1) along with monthly application of foliar fertilization of urea (1%) recorded better performance in growth of other foliage ornamental foliages such as Chlorophytum comosum, Tradescantia fluminensis, Rheo discolor, Peperomia obtusifolia and Epipremnum aureum under vertical garden systemItem Performance of celery (Apium graveolens L.) genotypes and nutrient management(Department of Plantation Spices Medicinal and Aromatic Crops, College of Agriculture , Vellanikkara, 2024-02-17) Sudhi, P; Nair Sunil Appukuttan; Malik Fasil, MItem Integrated nutrient management for enhancing growth, yield and quality of passion fruit (Passiflora edulis f. edulis Sims.)(Department of fruit science, college of agriculture , Vellayani, 2023-08-22) Akshara Rakesh.INTEGRATED NUTRIENT MANAGEMENT FOR ENHANCING GROWTH, YIELD AND QUALITY OF PASSION FRUIT (Passiflora edulis f. edulis SIMS.) The study entitled “Integrated nutrient management for enhancing growth, yield and quality of passion fruit (Passifloraedulis f. edulisSims.)”was carried out in the Department of Fruit Science, College of Agriculture, Vellayani during December 2020 to December 2021, with an objective of development of integrated nutrient management practice for passion fruit and to study the effect of integrated nutrient management on growth, yield and quality of passion fruit. The field experiment was conducted at the Regional Agricultural Research Station, Ambalavayal in Randomized Block Design (RBD) with 12 treatments and 3 replications. Purple passion fruit variety 134P was used for the experiment. The trial was conducted in combinations in which nitrogen requirement of the crop as per Ad hoc POP (25: 10: 25 g NPK vine-1 ) were replaced 25% and 50% with enriched vermicompost mixture which include neemcake, poultry manure, Azospirillum and PGPR mix-I, 1.5 times the Ad hoc Package of practice recommendation (37.5: 15: 37.5 g NPK vine-1 ) and lime application. The fertilizers were applied in three equal split doses, at planting, flowering and fruiting stage. Organic manure (10 kg FYM plant-1) as per Ad hoc POP was given uniformly to all treatments as basal except T12 (absolute control - no fertilizer application) .Urea, Rajphos and Muriate of Potash were used as fertilizer sources. Required quantity of lime based on soil analysis was applied in pits 10 days prior to planting. The results indicated that the application of N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation, increased the total yield of passion fruit. Plant girth was found to increase in treatment, N (25 %) as poultry manure enriched vermicompost and it showed highest plant girth at 4, 10 and 12 months after planting. Number of flowers produced per vine was highest with Ad hoc POP recommendation. The vines treated with N (25 %) as poultry manure enriched vermicompost + N (75%), P and K had the highest number of flowers produced per vine and the same treatment decreased the days taken for first flowering, days taken for first fruiting and days from flowering to harvest. There was also an increase in the number of fruits produced at 5, 6, 7 and 8 months after planting and total fruit production per vine in the treatment N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation. Fruit characters like the rind and pulp colour also improved with application of N (25 %) as poultry manure enriched vermicompost + N (75%), P and K, which recorded an increase in the fruit weight, seed weight and pulp weight while a decrease in rind weight100 seed weight was highest in fruits from the vines treated with N (50 %) as poultry manure enriched vermicompost + N (50%), P and K of Ad hoc POP recommendation. Regarding the fruit quality characters N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation, showed highest TSS, total sugar, sugar-acid ratio, carotenoid and ascorbic acid with lowest acidity level. The highest score for organoleptic evaluation of fruits were noticed with the application of N (25 %) as neem cake enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation Shelf life at ambient condition was increased with the application of enriched vermicompost in which N (25 %) as poultry manure enriched vermicompost + N (75%), P and K showed the highest value. The soil analysis revealed that pH could be brought to near neutral with initial lime application in N (25 %) as Azospirillum enriched vermicompost + N (75%), P and K of T1, NPK (25 %) as PGPR mix-1 enriched vermicompost + N, P and K 75% and N (50 %) as Azospirillum enriched vermicompost + N (50%), P and K . Highest EC value was recorded in 37.5: 15: 37.5 g NPK vine-1 + 10 kg FYM. Available Nitrogen was highest in N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation and available potassium was highest in N (50 %) as poultry manure enriched vermicompost + N (50%), P and K while NPK (50 %) as PGPR mix-1 enriched vermicompost + N, P and K 50% showed highest available phosphorous content.N (25 %) as Azospirillum enriched vermicompost + N (75%), P and K seemed to have the highest dehydrogenase activity in soil and organic carbon content was highest in N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation. Analysing the plant sample shows that the Nitrogen, Phosphorous and Potassium contents were highest in leaf samples from vines treated with 37.5: 15: 37.5 g NPK vine-1 + 10 kg FYM, N (50 %) as neem cake enriched vermicompost + N (50%), P and K and N (25 %) as poultry manure enriched vermicompost + N (75%), P and K respectively. Application of N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation recorded highest nitrogen content in fruits. Plants treated with 37.5: 15: 37.5 g NPK vine-1 + 10 kg FYM reported highest phosphorous content in the fruit sample. Regarding the net income and B:C ratio obtained, the application of N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc POP recommendation recorded the highest. Overall assessment indicated that adoption of Integrated Nutrient Management through application of N (25 %) as poultry manure enriched vermicompost + N (75%), P and K of Ad hoc package of practice (25: 10: 25 g NPK vine-1) given as three equal split doses (at time of planting, flowering and fruiting stage) was economically viable and it improved the growth, fruit yield and quality of passion fruit under Kerala conditions.Item Soil biodiversity under organic and integrated nutrient management system and impact on soil quality(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellayani, 2024-01-11) Divya S NairA study entitled “Soil biodiversity under organic and integrated nutrient management systems and impact on soil quality” was carried out with an objective to characterize soil biodiversity in coconut based cropping systems of southern laterites (AEU-8) of Kerala under organic and integrated soil management and to correlate soil biodiversity with soil quality and plant nutrient availability. The study involved soil sample collection and characterization of soil samples for soil biodiversity and soil properties. Soil samples were collected from coconut-based cropping systems under organic soil management in the Model Organic Farm, Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani (Site 1) and also from coconut-based cropping systems under integrated nutrient management in the Instructional Farm, College of Agriculture, Vellayani (Site 2). From each site, 10 composite soil samples each were collected from 0-15cm, 15-30cm and 30-60 cm depth. Soil samples were characterised for soil macro, meso and micro fauna, microflora and beneficial microorganisms. Soil biodiversity was estimated from a single, pooled sample of each site. The soil samples were analysed for their physical (soil texture, bulk density, particle density, porosity, soil moisture content and water stable aggregates), electrochemical properties (pH and EC), chemical (cation exchange capacity, anion exchange capacity, Total N, P, K, S, available N, P, K, Ca, Mg, S, B, Fe, Mn, Cu, Zn and organic carbon) and biological properties (microbial biomass carbon, dehydrogenase activity and amylase activity). Among the soil macrofauna, annelids, hymenopterans, isopods, dermapterans, myriapods and carabids were observed. Annelid population was highest in the surface soil of site 1 (40 no.m-2 ) and these varied significantly among the managements across all depths. Hymenopterans were observed only in surface soil and were found to be significantly higher in site 1 (6 no. m-2 ). Isopods were found only in surface soil of site 1 (1.33 no. m-2 ) and were not observed in site 2. The count of dermapterans were found to be higher in site 1 but there was no significant difference observed among the managements. Myriapod population (millipedes and centipedes) were observed only in the surface and subsurface soil of site 1. Carabids (ground beetle) were observed only in the surface soil of site 1. Among mesofauna, both acari and collembola were higher in the surface soil of site 1 (3983.33 no. m-2 and 4939.33 no. m-2 respectively). Acari population varied significantly among the managements at 0-15 and 15-30 cm soil depth while collembolans varied significantly across all depths. Soil microfauna (nematodes) was higher in the surface soil of site 1 (231830 no. m-2 ) and their population varied significantly among the managements across all depths. Soil microflora including bacteria, fungi, and actinomycetes were found to be higher in the surface soil under organic management (42.6 x 105 cfu g-1 , 18 x 103 cfu g-1 , 36 x 103 cfu g-1 respectively). Significant difference among both managements were found in abundance of all organisms at each depth except for fungi at 30-60 cm. Beneficial microorganisms including Azospirillum, Phosphate Solubilizing Bacteria (PSB) and K solubilizers were cultured and enumerated from both soil managements. The population of Azospirllum was higher in the surface soil of site 1 (7 x 103 cfu g-1 ) and these varied significantly among the managements at 0-15 cm and 15-30 cm soil depth. The count of PSB and K- solubilizers obtained in the culture media was too low to be recorded. The soil texture was found to be sandy clay loam for soil samples collected from both sites. The sand fraction was observed to be decreasing with depth, while silt and clay fractions increased with increase in depth. Significantly lower bulk density was observed in organic field (1.31 Mg/m3 in surface soil) at all depths and it increased with increase in depth. Higher particle density was observed in the surface soil of site 1 (2.34 Mg/m3 ) and no significant difference among the samples was observed at any depth. Higher porosity was observed in surface soil of site 1 (46 %) and it varied significantly among the managements across all depths. The mean soil moisture content was observed to be slightly higher in soil under INM at all depths, but no significant difference between the managements were observed. Water stable aggregates were higher in surface soil of site 1 (69.34 %) and it varied significantly among the managements across all depths. All the chemical properties except pH was found to decrease with increase in depth. The surface soil of site 1 recorded the significantly higher mean values for EC (0.21 dS m-1 ), CEC (6.97 C mol (p+ ) kg-1 ), total N (1986.88 kg ha-1 ), total P (969.92 kg ha-1 ), total K (1512 kg ha-1 ), total S (947.52 kg ha-1 ), available P (88.03 kg ha-1 ), available K (361.20 kg ha-1 ), available Zn (2.83 mg kg-1 ) and OC (0.96 %). All these properties showed significantly higher mean values in site 1 across all depths. The surface soil of site 2 recorded significantly higher mean values for pH (5.57), available N (222.5 kg ha-1 ), B (0.436 mg kg-1 ), Fe (16.79 mg kg-1 ) and Cu (0.99 mg kg-1 ). These properties varied significantly among the managements across all depths, except available B at 15-30 cm and 30-60 cm, and available Cu at 30-60 cm. While AEC, available Ca, Mg, S and Mn did not show significant difference among the management at any depth. The surface soil of site 1 recorded higher microbial biomass carbon (22.96 μg g -1 ), dehydrogenase (31.02 μg TPF hydrolysed g-1 soil 24 hr-1 ) and amylase (1.24 mU g-1 of soil) activity. All these biological properties decreased with increase in depth and were observed to be significantly higher in soil under organic management at all depths. Organisms observed a positive correlation with most of the physical, chemical and biological properties of soil. Negative correlation was observed between soil organisms and bulk density and also between hymenoptera and dermaptera with soil pH. From the Bray Curtis dissimilarity index, it is observed that the average dissimilarity of biodiversity was 0.262 between the surface soil of organic management and INM. This suggests that there are differences in species composition, although there are also shared species or similarities to some extent. Average dissimilarity among the managements decreased with depth. The PERMANOVA analysis showed that "depth" had a substantial and statistically significant effect, while the "management" factor did not significantly contribute to community dissimilarity. The interaction term "management × depth" also proved to be non-significant in explaining community dissimilarity. From the Bray Curtis dissimilarity index SIMPER analysis was performed and it showed that nematode is the species that contributes the largest amount of the difference between 0-15 cm and 15-30 cm soil depths and also between 15-30 cm and 30-60 cm soil depths. From this study, it was concluded that soil biodiversity was positively correlated to most of the soil properties and no significant effect was observed in the community dissimilarity for management but, depth had a substantial and statistically significant effect on community dissimilarity.Item Nutrient management with nano urea for enhanced herbage yield and quality of fodder sorghum (Sorghum bicolor (L) Moench)(Department of Agronomy, College of Agriculture , Vellayani, 2024-11-28) Sabavat Sandhya Sree; Sharu, S RThe study entitled “Nutrient management with nano urea for enhanced herbage yield and quality of fodder sorghum (Sorghum bicolor (L.) Moench)” was conducted during the period 2022-24 at College of Agriculture, Vellayani. The main objective of the study was to evaluate the effect of different concentrations of nano urea on growth, yield, quality and economics of fodder sorghum. The field experiment was conducted at the Instructional Farm, during the period from December 2023 to February 2024. The experiment was laid out in randomized block design with 13 treatments, replicated thrice. The treatments comprised nitrogen management and foliar nutrition. The treatments were T1: 75% Recommended dose of nitrogen (RDN) + nano urea (0.2%); T2: 75% RDN + nano urea (0.4%); T3: 75% RDN + nano urea (0.6%); T4: 100% RDN + nano urea (0.2%); T5: 100% RDN + nano urea (0.4%); T6: 100% RDN + nano urea (0.6%); T7: 75% RDN + urea spray (2%); T8: 100% RDN + urea spray (2%); T9: nano urea (0.2%) alone; T10: nano urea (0.4%) alone; T11: nano urea (0.6%) alone; T12: KAU POP; T13: control (without nitrogen). The variety used for the study was CNFS-1 released from Zonal Agricultural Research Station, VC Farm, Mandya. The fertilizer recommendation followed was 60:40:20 kg NPK ha-1, along with farm yard manure (10 t ha-1). Foliar spray of nano urea and urea were done at 20 DAS and 40 DAS. All other management practices were followed as per the KAU package of practices recommendations. Nitrogen management and foliar nutrition had significant influence on the growth and yield attributes of fodder sorghum. At 30 DAS, taller plants (75.52 cm) were observed in T5 and was on par with T6. The treatment, T6 resulted in taller plants (132.41 cm and 226.62 cm) at both 45 DAS and harvest and remained on par with T5. Similarly, at 30 DAS, T6 exhibited more number of leaves per plant (6.41), leaf length (47.12 cm), leaf breadth (3.64 cm), leaf area per plant (661.68 cm2), LAI (1.44), stem diameter (11.06 mm), number of internodes per plant (5.24), length of internode (4.38 cm) and leaf: stem ratio (0.39) which was comparable with T5. Similarly, the treatment, T5 resulted in maximum number of leaves per plant (7.54 and 8.99), leaf length (63.47 cm and 89.00 cm), leaf breadth (4.69 cm and 5.61 cm) and length of internode (13.07 cm and 19.95 cm) at both 45 DAS and harvest and was on par with T6. However, higher leaf area per plant at harvest (2682.69 cm2), LAI (3.52) and number of internodes per plant (6.80) at 45 DAS were observed in T6 and remained on par with T5. The treatment, T5 resulted in more number of internodes per plant at harvest (9.67) and was on par with T6. Similarly, leaf area per plant (1586.64 cm2) at 45 DAS and stem diameter (12.94 mm and 15.19 mm) at both 45 DAS and harvest were observed in T6 and was statistically comparable with T5 and T3. Green fodder yield (32.03 t ha-1), dry fodder yield (5.81 t ha-1) and per day productivity (0.53 t ha-1 d-1) were found significantly higher in the treatment, T5 and remained on par with T6. The treatment T5 exhibited higher total chlorophyll content (1.92 mg g-1 FW and 2.83 mg g-1 FW) at both 30 DAS and 45 DAS and was statistically comparable with T6. Higher crude protein content (9.92 %) and crude protein yield (0.50 t ha-1) were observed in T5 and was on par with T6. The treatment T5 resulted in higher N content and NPK uptake which was comparable with T6. The organic carbon and available N, P and K status of soil after the experiment did not vary significantly with nitrogen management and foliar nutrition. The treatment, T5 (100 per cent RDN + nano urea 0.4 per cent) fetched higher net return of ₹ 92221 ha-1 with BCR of 2.36 and was comparable with T6. Based on the study it could be concluded that nitrogen management along with foliar application of nitrogen based formulations improved the growth, yield, quality and economics of fodder sorghum. There was an increased yield of green fodder (39. 26%) when nano urea (0.4%) was supplemented with RDF compared to urea spray (2 %). When the fertilizer level was decreased by 25 percent, growth, yield, quality parameters and net return were also found to be reduced. Thus, the result of the research work revealed that soil application of 100 per cent RDF (60:40:20 NPK kg ha-1) along with foliar spray of nano urea, 0.4 per cent each at 20 DAS and 40 DAS was beneficial for growing fodder sorghum in terms of growth, yield, quality and economics in Kerala during the rabi season.Item Nutrient management in finger millet (Eleusine Coracana (L) Gaertn)(Department of Agronomy, College of Agriculture, Vellanikkara, 2024-02-15) Ribin Usman, T; Syama S MenonThe study entitled “Nutrient management in finger millet [Eleusine coracana) (L.) Gaertn.].” was undertaken at the Agronomy Farm, College of Agriculture, Vellanikkara during October 2021 to February 2022. The objective of the experiment was to standardize the optimum nutrient dosage for maximum growth and yield of finger millet. The experiment was laid in randomized block design with eight treatments with replicated thrice. The plot size was 4.8 m x 4 m and transplanting were done at a spacing of 30 cm x 10 cm. The treatment included different levels of nutrients which was compared with an absolute control (T1–5 t FYM ha-1 ,T2–5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1, T3-5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1, T4- 5 t FYM ha-1 + 50: 25: 25 kg NPK ha-1, T5- 5 t FYM ha-1 + 40: 20: 20 kg NPK ha-1, T6- 5 t FYM ha-1 + 30: 15: 15 kg NPK ha-1, T7- 5 t FYM ha-1 + 20: 10: 10 kg NPK ha-1). The ragi variety used for the study was Hima. The results of the experiment revealed that plant height washigher in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1at 30 DAT (75.33 cm), flowering (76.63 cm) and harvest (77.90 cm) which was on par with 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1and 5 t FYM ha-1 + 50: 25: 25 kg NPK ha-1.Significantly higher leaf area index recorded highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (2.91). Higher number of fingers per panicle, weight of grains per panicle and dry mater production (at 30 DAT, flowering and harvest) also showed the same trend with significantly highest values in higher level of fertilizer dose (5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1). Significantly highest yield was recorded in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(1523 kg ha-1) followed by 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1,. Similarly highest straw yield was also noticed in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(2568 kg ha-1) followed by 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1, which was on par with other lower dose of fertilizers. This is due to, increased availability of the nutrients in the root zone enabled higher uptake of the nutrient and it led to a better nutrient status in plant system. On the other hand, the increased net photosynthesis and increase in mobilization of photosynthates toward the reproductive structure contributed to grain yield. Crude protein content, even though significantly different, the values are on par with different levels of fertilizer doses and recorded higher in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1, 5 t FYM ha-1 + 60: 30: 30 kg NPK ha-1 and t FYM ha-1 + 50: 25: 25 kg NPK ha-1 than absolute control. This can be due to higher nitrogen contents present in these treatments as evidenced by the higher N uptake values.Calcium content in the grain was highest in 5 t FYM ha-1(431.6 mg 100 g-1) and showed a reduced content in5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (419.4 mg 100 g-1). Iron and fibre content was not influenced by application of nutrients levels. Nitrogen, phosphorus and potassium uptake by ragi was highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 (59.58, 31.39 and 65.73 kg ha-1 respectively). It followed the same trend as that of dry matter production. The available nutrient status in the soil after the experiment in general showed a decrease due to plant utilization.P status varied significantly with treatment combination, while the changes in available N and K were not significant. Available phosphorus content was recorded highest in 5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1(75.13 kg ha-1), Highest net income (Rs. 28,355 ha-1) and BC ratio(1.43) was obtained in5 t FYM ha-1 + 90: 45: 45 kg NPK ha-1 due to maximum yield compared to other nutrient levels. From the results it can be concluded that application of FYM @5 t ha-1as basal and NPK @90: 45: 45 kg ha-1, where full dose of P and K along with half dose of N applied as basal and the remaining half of N applied 30 DAT will result in higher yield and net returns. Hence, can be recommended for the high yielding finger millet variety Hima in AEU 10 (North Central Laterite of Kerala) and multi location trials are required to arrive at a final recommendation.Item Nutrient management in cassava (Manihot esculenta Crantz) variety Vellayani Hraswa for southern laterites (Agro ecological unit 8)(Department of Agronomy, College of Agriculture ,Vellayani, 2024-06-01) Aparna, R A.Phosphorus transformation in acid sulphate rice soils of Kerala Acid sulphate soils are lowland soils situated below the mean sea level along the coastal tracts of Kottayam, Alappuzha, Thrissur and Malappuram districts of Kerala, spread in two agro-ecological units namely Kuttanad (AEU 4) and Kole lands (AEU 6). These soils are characterised by high levels of organic matter, low pH and toxicity of iron (Fe) and aluminium (Al) with wide variability in available phosphorus (P) content. Acid sulphate soils generally contain substantial quantities of Fe sulphide minerals or the oxidation reaction products of these sulphidic minerals and the protonated/non-protonated surfaces of Al/Fe hydroxides and oxides, resulting in P sorption and formation of the complexes, thus decreasing P availability in soil. However, the recent fertility evaluations across the state showed high available P status due to solubilization of the accumulated applied P. To develop an economically viable phosphorus nutrient management strategy, a pioneer study on P transformations in acid sulphate soils is highly required. The study aimed to understand seasonal variation of nutrients and transformations of phosphorus in acid sulphate soils. The investigation was conducted at Radiotracer laboratory, College of Agriculture, Vellanikkara, with four experiments viz., collection and characterization of soil samples from the acid sulphate soils of Kerala in two seasons, fractionation of phosphorus, adsorption study and an incubation study. In the first experiment, 125 representative soil samples from Kuttanad (AEU 4) (15 each from Upper Kuttanad, Lower Kuttanad, Vechur Kari, Purakkad Kari and Kayal lands) and Kole lands (25 each from Thrissur and Ponnani Kole) in pre-monsoon (April) and post-monsoon (November) were collected and characterised. The experiments on the fractionation and adsorption of phosphorus were done in thirty-five samples ie., five each from the seven selected locations with varying available P status. Phosphorus fractionation was carried out to quantify different fractions of phosphorus and their contribution to the available pool. The inorganic P fractions includes saloid bound P, Fe-P, Al-P, reductant soluble P and Ca-P. Adsorption study was carried out to work out the quantity/ intensity (Q/I) relationship of phosphorus and the pattern of adsorption in acid sulphate soils. Finally, an incubation experiment of 90 days duration was conducted to understand the effect of phosphatic fertilisers, lime and farmyard manure at different levels in low and high available P soils collected from Kuttanad and Kole lands. The treatment details of the incubation study were three levels of phosphatic fertilisers (as SSP - 0, 35 and 70 kg ha-1), two levels of lime (as CaO - without lime and lime as per POP recommendations) and two levels of farmyard manure (0 t ha-1 and 5 t ha-1). The observations were made on 30th, 60th and 90th days of incubation. Seasonal characterisation of soil samples during the two seasons revealed that among the collected samples, 50 per cent was sandy clay loam and 40 per cent was sandy loam in texture. The acidity characterisation of soil samples reaffirmed the extreme acidity condition of acid sulphate soils with 40 per cent of samples coming under extremely acidic class and 20 per cent under very strongly acidic. Among the collected soil samples, 37.60 per cent was low in available P, 23.20 per cent and 39.20 per cent under medium and high P respectively. The soil sample from Vechur Kari region showed the highest value of organic carbon (11.46 %). The available micronutrients viz., Fe and Mn showed very high concentrations. Among the acidity fractions, potential acidity was dominant followed by pH-dependent acidity in both seasons. Seasonal variation in electrochemical properties like pH and EC was noticed between two seasons. Ultra acidic soil reaction with high electrical conductivity was noticed during pre-monsoon period which reaffirm the salt water intrusion in these locations. Oxidation of pyrite mineral resulted in high amount of available sulphur as well as potential acidity during pre-monsoon. Reduced condition prevailing in the post monsoon resulted in high concentration of available iron. The fractionation study of phosphorus indicated that the per cent distribution of different phosphorus fractions followed the order, Fe- P > organic P > reductant soluble P > calcium P > aluminium P > saloid bound P. The contribution of dominant fraction (Fe-P) to the available P is mainly through saloid bound P. The phosphorus fixing capacity was significantly and positively correlated with clay, organic matter content, and negatively correlated with the available P. In the adsorption study, high buffer power indicated the ability of acid sulphate soils to replenish the depleted available P. Freundlich adsorption isotherm was found to be the best to explain P adsorption followed by Langmuir and Temkin adsorption isotherms. The Freundlich adsorption constant, KF was found to be correlated with organic matter which confirmed the fixation of phosphorus by organic matter in acid sulphate soils. In most of the soils, Langmuir adsorption constant (KL) increased with rise in temperature, indicates chemisorption behaviour of P adsorption. The incubation study affirmed that in soils with low available P, the addition of SSP at doses of 70 kg ha-1 and 35 kg ha-1 along with lime and FYM showed a significant increase in pH. In these soils, the addition of SSP (70 kg ha-1) along with lime and FYM registered the highest available P of 51.63 and 73.33 kg ha-1 respectively in Kuttanad and Kole soils at 60th day of incubation. In the same treatment, Fe bound P fraction was found to be highest with a decreasing trend towards 60th day of incubation, which increased after that. In the case of soils with high available P, the treatment combination with the addition of the highest dose of SSP (70 kg ha-1) along with lime and FYM showed the highest pH with an increasing trend towards 60th day. On the contrary to low P soils, in high P soils, the addition of SSP at 35 kg ha-1 along with lime and FYM registered the highest available P of 309.44 and 126.94 kg ha-1 respectively in Kuttanad and Kole at 30th day of incubation followed by a reduction towards 60th day of incubation. Phosphorus, a widely varying nutrient in acid sulphate soils is prone to high adsorption and fixation in soil depending upon the type of clay, organic matter content and amount of oxides and hydroxides of Fe and Al. There was no significant seasonal variation of P in soil samples from AEU 4 and AEU 6. In acid sulphate soils, the most dominant fraction, Fe-P contributed to available P mainly through saloid bound P, which is the water-soluble and loosely bound P fraction. The reduction of available P with the increase in P fixing capacity necessitates its estimation at least for the grouping of soils for the efficient management of phosphorus. In soils with high available P, addition of lower dose of SSP (35 kg ha-1) along with organic manure (FYM @ 5 t ha- 1) and lime (POP recommendations) is sufficient to enhance the P availability. Where as, in soils with low available P, addition of higher dose of SSP (70 kg ha-1) along with organic manure (FYM @ 5 t ha-1) and lime (POP recommendations) enhanced the P availability than its sole application. In this regard, field experiments in acid sulphate soils have to be conducted to confirm the results of incubation study in rice under natural system and more investigation is needed to know the interaction between organic matter and organic P fraction. As the organic matter plays the dual function in the environment- as a link and as a bottleneck for phosphorus availability, detailed study should be undertaken to know the complex formed by P fixation and its degree of crystallinity for developing better P management strategies in acid sulphate soils.Item Integrated nutrient management in sofghum (Sorghum bicolor L. Moench) for AEU 8(Department of Agronomy, College of Agriculture, Vellayani, 2023-03-17) Arathy P Shaji; Rajasree, GItem Impact of long term integrated nutrient management system on soil health and rice productivity(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2017) Rakhi, R; Rani, BItem Studies on fertigation in bitter gourd (Momordica charantia L.)(Department of Agronomy,College of Agriculture, Vellayani, 2016) Anjali A Hari; Girija Devi, LThe research project titled “Studies on fertigation in bitter gourd (Momordica charantia L.)” was undertaken in the farmer’s field at Pirappancode, Thiruvananthapuram district, during March 2015 to June 2015, to standardize the fertigation schedule for precision farming in bitter gourd, to assess the impact of precision farming practices on growth and yield of the crop and to work out the economics. The experiment was laid out in split plot design with four replications. The main plot treatments included four fertigation levels (l), viz., l1- 75 per cent recommended dose (RD) of N and K, l2- 100 per cent RD of N and K, l3- 150 per cent RD of N and K and l4- 200 per cent RD of N and K. Fertigation intervals (i) (i1- fertigation at 4 days interval and i2- fertigation at 8 days interval) formed the sub plot treatments. Two controls were included in the study, viz., control 1- Kerala Agricultural University (KAU) ad hoc recommendation for precision farming and control 2- KAU Package of Practices (POP) recommendation. Uniform application of P @ 25 kg ha-1 in all treatments except control 1. The results revealed that the growth attributes like number of leaves at 35 days after sowing (DAS), leaf area index (LAI) and days to first female flower appearance were influenced by fertigation levels and vine length (20 and 35 DAS) and leaf production (20 DAS) were influenced by fertigation intervals. The number of leaves (35 DAS) was the highest in l2, while l3 produced the highest LAI (55 DAS). The female flower appearance was early in l1 and late in l4. Fertigation with l2 recorded the highest fruit yield (4.26 kg plant-1 and 21.30 t ha-1) fruit number (31.76), number of harvests (5.74), total dry matter yield (636.92 g plant-1) and ascorbic acid content (54.05 mg 100 g-1), while the same level of nutrient through conventional method of application (control 2) gave a comparable fruit yield (3.41 kg plant-1 and 17.05 t ha-1) and protein content (23.18 per cent) as that of fertigation treatment and also registered the highest content of TSS (3.250 Brix) and K (4.19 per cent). Water use efficiency (WUE) and water productivity were found to be influenced by fertigation levels with l2 recording the highest (24.41 and 3.65 kg ha mm-1 respectively). The uptake of nutrients particularly P and K were the highest in l2. Also K uptake was the highest in both the controls than in fertigation treatments. Fertigation at 8 days interval recorded the highest N uptake. Fertigation treatments and control 1 improved the N and K status of soil, while N status improved and K decreased in control 2. Economic analysis revealed the superiority of fertigation treatments over both the controls and within fertigation levels, the level l2 as reflected in the respective B:C ratios. The mean B:C ratio in fertigation was 4.29 and in l2, it was 4.94. The B:C ratio recorded in the two controls were 2.74 and 3.21 respectively. Similarly the net income was the highest in l2i1 ( 6,90,488 ha-1), the lowest in control 2 ( 4,69,412 ha-1), and though control 1 gave a comparable fruit yield, its economics in respect of B: C ratio and net income were the lowest. The results of the study revealed that the current nutrient recommendation of KAU (70:25:25 kg N, P2O5 and K2O ha-1) is sufficient for bitter gourd, but giving it through fertigation, the yield can be further increased. Based on the results, a fertigation schedule of 152 kg ha-1 urea and 53 kg ha-1 MOP at 4 days interval along with a basal dose of 100 kg ha-1 rajphos (equivalent to 70:20:32 kg N, P2O5 and K2O ha-1 modified from KAU recommendation of 70:25:25 kg N, P2O5 and K2O ha-1 as per soil test) can be given as a recommendation for precision farming in bitter gourd for high yield, quality produce and the highest net income and B:C ratio