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ThesisItem Open Access Soil and vegetation characteristics in the post flood scenario in selected tree based land use system in Thrissur, Kerala(Departmemt of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2020) Arshad, A; KAU; Jamaludheen, VThe unprecedented and intense nonstop rainfall for days together occurred in Kerala during August 2018 affected all the aspects of human lives including socio economic conditions, transportation, infrastructure, agriculture, and livelihood. Flooding lead to food crop shortages due to the loss of entire crop harvest and degradation of soil quality. The present study is aimed at identifying the impacts of Kerala flood 2018 on soil physico – chemical and biological properties, vegetation and soil seed banks along the ‘Kurumali’ river basin of Thrissur district of Kerala in five major land use systems prevalent in the area viz; forest, rubber, nutmeg and coconut plantations and open land. For this purpose, all five land use systems in flood affected and the same five land use systems in the adjacent area where flood has not been affected were selected. Soil samples were collected up to one meter soil depth (0-20 cm, 21- 40 cm, 41- 60 cm,61- 80 cm and 81- 100cm) for soil analysis after seven months of flood . Soil physical properties like soil bulk density, soil porosity and soil texture; and chemical properties like soil pH, EC, available N, P, K; secondary nutrients like Ca, Mg and Sulphur and micronutrients like Fe, Cu, Mn, Zn and Boron were analysed. The biological properties assessed were total microbial count (Bacteria, Fungi and Actinomycetes), dehydrogenase activity and microbial biomass carbon. Soil seed bank data were generated in two seasons (Pre- monsoon and post- monsoon of 2019) from the top soil of all the five land use system studied. In vegetation analysis diversity indices, abundance and dominance of species were worked out. The bulk density and porosity had a little effect due to flood in all land use systems while soil texture had changed from sandy clay loam to clay loam structure in forest flood affected system. In coconut, it is changed from loamy texture to sandy clay loam and in open, the change was from loamy sand to silty clay loam in the surface soil ie. 0- 20 cm depth. The pH had a significant increase after flood in forest and open land use system (0.31 and 0.26, respectively). The rubber and coconut flood affected systems had a significant decrease (0.16 and 1.34, respectively) in pH from flood non affected condition. The EC had a significant decrease after flood in rubber, coconut and open land use system (0.9dS m-1, 0.8 dS m-1 and 0.37 dS m-1 , respectively). The organic carbon content in forest, rubber and nutmeg flood affected land use system had showed a significant increase (0.2 %, O.8 % and 0.4 % , respectively) from flood non affected condition; whereas coconut and open flood affected land use system had showed a significant decrease in organic carbon (1.3 % and 0.7 % , respectively) from flood non affected condition. The forest flood affected had showed a significant increase (84kg ha-1) in available N from flood non affected condition. Rubber, nutmeg and open flood affected system had showed a significant decrease (201.6 kg ha-1, 35.7 kg ha-1 and 207.9 kg ha-1 , respectively) in available N from flood non affected condition. The effect of flood on available P also showed similar trend of OC at the soil depth of 0-20 cm. The forest, coconut and open flood affected land use system had a significant decrease (196.6 kg ha-1 421.5 kg ha-1and 125.8 kg ha-1 , respectively) in available K from flood non affected system. While rubber and nutmeg flood affected system showed a significant increase (299.4 kg ha-1and 292.0 kg ha-1respectively) in available K. The nutmeg plantation had a significant increase (9193 mg kg-1) while coconut plantation had significant decrease (1840.6 mg kg-1) in calcium content of soil after flood. Similarly the nutmeg plantation had a significant increase (174.1 mg kg-1) whereas coconut plantation had a significant decrease (131.4 mg kg-1) in magnesium content of soil after flood. The rubber plantation had a significant decrease (7.744mg kg-1) after flood in sulphur content of the soil. The forest had a significant increase (4.49 mg kg-1) in ‘Fe’ content after flood while open land use system had a significant decrease (5.43 mg kg-1) at the depth of 0- 20 cm. The forest, rubber and nutmeg had showed a significant increase (39.14 mg kg-1, 21.78 mg kg-1and 55.71 mg kg-1respectively) after flood in manganese content of soil at the depth of 0-20 cm. While coconut and open land use system had a significant decrease (60.22 mg kg-1and 19.39 mg/kg, respectively) in manganese content after flood. The rubber and nutmeg had a significant increase (40.46 mg kg-1 and 7.29 mg kg-1 , respectively) in copper content of soil after flood at the depth of 0-20 cm. Open land use system was also recorded with a significant increase (9.39 mg kg-1) in copper content of soil after flood at the depth 0- 20 cm. Forest, rubber and nutmeg plantation had a significant increase (1.07 mg kg-1, 2.13 mg kg-1 and 17.32 mg kg-1 , respectively) in zinc content after flood at the depth of 0-20 while, coconut and open land use system had a significant decrease (6.44 mg kg-1 and 1.56 mg kg-1 , respectively). Total microbial count (Bacteria, Fungi and Actinomycetes) had no significant difference after flood in any of the land use systems. With respect to the dehydrogenase activity, the entire four tree based land use systems remained without any appreciable change. The forest, rubber and nutmeg land use systems also had an increase (9.67g g-1, 64.48 g g-1 and 25.89 g g-1 respectively) in microbial biomass carbon after flood. While coconut and open land use system had a decrease (90.98 g g-1and 121.44 g g-1, respectively) in MBC after flood. Soil seed bank had no effect due to flood. The present study reveals that among the five land use systems, Forest land use system showed a comparatively neutral effect in some and a distinctive positive effect in most of the soil physico - chemical and biological properties after seven months of flood. The results implicated that the forest land use system was the least affected or reselient with respect to soil properties due to flood impact. The seed bank generated not showed any noticeable difference after flood. The flood has no serious effect on higher vegetation.ThesisItem Open Access Biopriming techniques for better germination and seedling growth of sandal (santalum album L.)(Department of Silviculture and Agroforestry, College of Forestry, Vellayani, 2020) Anjali, K S; KAU; Jijeesh, C MSeed priming is the process of controlled hydration of seeds to a level that permits pre-germinative metabolic activity to proceed, but prevents actual emergence of the radicle. Seed priming with living bacterial inoculums is known as biopriming, which involves the application of plant growth promoting rhizobacteria (PGPR), resulting in enhanced germination, plant growth and disease résistance. Santalum album, L is a semi-root parasitic tree distributed in South India and is one of the most valuable and world renounced timber species. The poor germination rate combined with the long germination period is a major limitation in the regeneration of sandal. The present study was formulated to evaluate the effect of seed biopriming procedures on the germination and seedling performance of Santalum album. The biopriming agent’s viz. Pseudomonas fluorescens, Trichoderma viride, PGPR II at concentrations 25, 50, 75 and 100% and durations 1, 2,3,4,6 and 8 days and hydropriming for the same duration constituted the treatments of the study. The primed seeds were sown after the post priming storage for one day and one week. The results indicated that, for the post priming storage of one day, biopriming with T. viride at 100 % for 1 day (73.3%) followed by T viride at 75% for 1 day (35.96%) recorded the highest germination and the lowest was on biopriming with P. fluorescens at 50% for 2 days (0 %). Whereas, for post priming storage of one week, the highest germination was obtained on biopriming with T. viride at 100% for 3 days (82.72%), followed by P. fluorescens at 100% for 6 days (81.27%) and the lowest germination was obtained for the seeds bioprimed with PGPR II at 25% for 1 day and PGPR II at 100% for 3 days (0%). The shortest imbibition period was observed for the seeds bioprimed with P. fluorescens at 100% for 8 days (13 days) for one day storage and for the seed subjected to post priming storage of one week, for majority of the treatments, the imbibition period was reduced to 15 days. The electrical conductivity of the seed leachates, was the maximum for the seeds hydroprimed for 3 days (1.469 dScm-1) and the lowest was in hydropriming for 6 days (0.172dScm-1) and for the seeds subjected to biopriming the range of electrical conductivity varies from 0.266 dS cm-1 (PGPR II at 100% for 1 day) to 1.32 dScm-1(T. viride at 75% for 6 days). Biochemical analysis of the seeds after priming indicated that the total carbohydrate was maximum on biopriming with T. viride at 25% for 3 days (0.772 mg g-1) and the lowest value was on biopriming with P. Fluorescens at 50% for 6 days (0.088 mg g-1). The total protein was maximum for the seeds treated with PGPR II at 25% for 4 days (0.077 mg g-1) and the lowest was for those treated with T. viride at 50% for 2 days (0.016 mg g-1).Crude fat content of the primed seeds was maximum for the seeds treated with P. fluorescens at 100% for 3 days (73.2%) and the minimum for those treated with T. viride at 75% for 1 day (34%). Seedling growth and biomass production were recorded at 30 and 180 days after transplanting. In the context of seedling attributes, the maximum seedling height is observed for the seeds bioprimed with PGPR II at 100% for 2 days (27.2 cm), the largest collar diameter was for T viride at 25% for 4 days (4.08mm) and the maximum number of leaves is obtained for T viride at 75% for 8 days (26.7) for the seeds subjected to post priming storage of one day. For one week storage, the largest value for seedling height is obtained for seeds bioprimed with P. fluorescens at 100% for 8 days (28.10 cm), the collar diameter was obtained maximum for biopriming with P. fluorescens at 100% for 8 days (5.63 mm) and the largest number of leaves is obtained for T. viride at 100% for 1 day (23.7). Hierarchical cluster analysis indicated that the best seedling performance was on biopriming with T. viride at 25% for 4 days for one day storage and P. fluorescens at 100% for 8 days, for the seeds subjected to post priming storage of one week at 30 and 180 days after transplanting. The present investigation confirms the superiority of biopriming treatments in improving the germination and seedling performance of the sandal and biopriming being an eco-friendly treatment that can be recommended for the quality planting stock production of sandal.
