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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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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.ThesisItem Open Access Understorey productivity of agrisilivicultural systems as affected by tree population density and fertiliser regimes(Department of Silviculture and Agroforesty, College of Forestry, Vellanikkara, 1996) Joseph, Thomas; KAU; Mohan Kumar, BA split plot experiment, involving ailanthus (Ailanthus triphysa (Dennst.) Alston.) at various population densities (3333, 2500, 1600 and 1111 TPHA) and fertiliser regimes (0:0:0, 50:25:25, 100:50:50 and 150:75:75; kg N:P2O5: K2O ha-1 Yr-1), initiated in June, 1991 was intercropped with ginger (Zingiber officinale Roscoe). Additional treatments included monocultures of ginger and ailanthus. Objectives were to assess the productivity of ginger as a component of an agrisilviculture ststem involving ailanthus, besides analysing the partitioning of solar radiation among the different components of the system and characterising the nature of below ground interactions between the field and tree crop components. Ailanthus growth and its foliar chemical composition was not influenced by tree population density and fertiliser regimes. Light availability below the canopy was, however, strongly altered by tree population density. Availability of photosynthetically active radiation (PAR) was inversely proportional to stand density. Available PAR ranged from 35-72 per cent and 40-75 per cent of that in the open, at 50 and 150 cm above the ground level respectively. A strong relationship however, could not be established between light availability and foliar nitrogen content of the tree. Ginger grown in the interspaces of ailanthus exhibited better growth as compared to the sole crop situation. Tissue nutrient content of ginger in the later stages were higher when grown as mixed crop. The tree population density of 2500 trees per hectare (TPHA) registered better growth of understorey ginger. Fresh and dry rhizome yield of ginger also was maximum at this density. However, no strong relationship could be established between light availability and rhizome yield of ginger. Fertilisers applied to the tree component of the system, did not influence the growth, yield and quality of ginger. Three years of tree growth significantly reduced soil nutrient status below trees. A reduction in soil PH also was observed. Radiophosphorus recovered by ginger and ailanthus were not substantially altered by tree population density, lateral distance of application and cropping situation. However, ailanthus absorbed a substantial portion of the fertilisers applied to the ginger crop. Root activity of ailanthus suggests that 41-53 per cent of active roots are situated at about 40 cm from the tree trunk. Neighbouring trees in the high density stand registered a high recovery of 32P as compared to the low density stand, which may have important management implications.ThesisItem Open Access Diversity, structure and standing stock of timber in the homegardens of Thrissur district, Kerala(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2017) Subu, R Unnithan; KAU; Kunhamu, T KTropical homegardens are time-tested land use systems which have evolved through generations of crop intensification. Homegardens of Kerala are traditional agricultural systems that were closely related to the livelihood and nutritional security of small and marginal farmers of Kerala. A study was carried out to investigate the functional and structural status of the homegardens in Thrissur District, Kerala. Study was conducted in selected homegardens of 10 panchayths and one peri urban area of Thrissur district. The study was based on comparison of homegardens of three size classes such as small (<0.2 ha), medium (0.2-0.4 ha) and large (>0.4 ha) from three eco regions (highland, midland and coastal land) and one peri urban area (municipality). A total of 330 homesteads were selected from selected panchayths based on a stratified random sampling. There was a great variability in diversity, abundance and standing stock of different tree species belongs to different use categories among three homegarden size classes and across different eco regions. There were 163 total species present in the entire Thrissur district that included 122 trees species and 41 agricultural crop species. Contrary to earlier studies, consistent decline in diversity was observed with decrease in homegarden size. Highest number of taxa was observed from large homegardens (102 species) which was followed by medium (95 species) and small (85 species). Population pressure and skewed land availability may have negatively affected the species diversity in homegardens. Most abundant functional group of trees found in surveyed homegardens were medicinal trees (62 species) followed by timber species (53 species). Economically important functional groups such as timber, fodder, fuel, green manure and other MPTs were abundant in large homesteads. Eco-region wise comparison of tree diversity suggested high diversity in the midland and highland regions while lower in coastal land and peri-urban areas. Mangifera indica was the predominant timber tree species in terms of abundance and standing stock in Thrissur district with a total stand number and standing stock projected to the Thrissur district as 15,98,849 and 18,84,356.3 m3 respectively. Other dominant timber trees in terms of standing stock were Artocarpus heterophyllus, Tectona grandis, Swietenia macrophylla, etc. Standing stock per hectare of total timber species identified in Thrissur district was 55.12 m3 ha-1 and projected standing stock of all timber species in the district was 81,38,931.6 m3. Vertical diversity of the studied homegardens suggested high species richness associated with middle storey. Also all three strata of large homegardens were more diverse than medium and small homegardens irrespective of eco-region. In total there were 41 species of agricultural crops and medicinal plants identified from selected homegardens. Musa sps., Areca catechu and Cocos nucifera were the predominant species of all size holds. Simpson Index and Shannon Diversity Indices of agricultural crops of all size holds showed no large difference. Attempts to study the socio-economic factors of homegarden functioning revealed land fragmentation as the principal agent of their decline. The most frequent constraints of homegardens included high wage of the labourers involved in homegarden maintenance, less labour availability, large expense/less profit, pest and disease, etc. Wood quality assessment of Tectona grandis, Artocarpus heterophyllus and Swietenia macrophylla using NDT showed that oven dry specific gravity (SPGo.d) has no influence on eco-regions and tree size classes. The dynamic modulus of elasticity (MOEdyn) showed significant differences for Artocarpus heterophyllus and Swietenia macrophylla across eco-regions. However, this was not prominent for Tectona grandis. On the whole, the functional and structural analysis of the homegardens in Thrissur district of Kerala revealed their potential contribution to the agro-biodiversity. However concerted efforts are required to revitalize these unique traditional agricultural practices in terms of their ecological and economic viability.ThesisItem Open Access Fine root dynamics and associated carbon and nutrient flux in 12 year old acacia mangium at varying stand densities(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2017) Delphy Rocha; KAU; Kunhamu, T KFine root production has been estimated to account for up to 33% of global annual Net Primary Production, NPP (Gill and Jackson, 2000). Thus, fine root turnover has important implications for individual plant growth, plant interactions, and below-ground carbon and nutrient cycling. Direct and indirect methods for measuring fine root production and turnover in 12 year old Acacia mangium Willd. at varying stand densities were studied. Fine root production estimated ranged from 3.8 - 5.75 Mg ha-1 with a turnover of 4 yr-1. It was estimated that through fine root decomposition about 1.36-2.39 Mg C ha-1, 34.56- 102.52 kg N ha-1, 1.46-3.3 kg P ha-1 and 19.94-33.60 kg K ha-1 is released to soil. Even though fine root constitutes only 1.7-2.14% of the total tree biomass its contribution to the system productivity is very high. Attempts were also made to relate fine root production with various growth variables and in general most of the variables (DBH, basal area per tree, volume per tree, aboveground biomass per tree and leaf area per tree) gave good correlation (R>8**) with fine root production when considered on per tree basis. Average annual litter production was estimated to a range of 9.99-11.69 Mg ha-1. Interestingly, annual litter production had a high correlation (R=0.9**) with fine root production. Through litter decomposition, 1.4-2.07 Mg C ha-1, 36-48 kg N ha-1, 1- 4 kg P ha-1 and 3-6 kg K ha-1 is released to the soil. Total soil carbon stock up to 1m soil depth was estimated and it was significantly different across different density regimes. Invariably the SOC concentration was relatively lower in treeless plot compared with A. mangium at different density regimes. Soil C sequestration was 15.96 - 34.58 Mg C ha-1 and the nutrient content of soil estimated as 2343.811-948 kg N ha-1, 13.12-21.92 kg P ha-1, 313.52-261.25 kg K ha-1. Total system C content estimates in the ranges from 148.93 -263.79 Mgha-1. So Density manipulation plays a significant role on productivity in 12 year old A. mangium. Hence, management objectives should be based on assessment of their impact on various productivity attributesThesisItem Open Access Long term effect of thinning on productivity and wood properties for twenty year old Acacia mangium wild stands(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2017) Suresh Ramanan, S; Kunhamu, T KThe focus of forest management in India has moved from timber production to conservation and eco-restoration. Hence, plantations are the viable scope for meeting our ever increasing wood demand. Effective stand management practices are indispensable for deriving optimal productivity from these plantations. Thinning is generally recognised as an important silvicultural tool for creating qualitative and quantitative improvement in plantation productivity. However, its temporal effect varies with species and thinning regime. In this context, the present study was undertaken by destructive sampling of trees and assessing the aboveground and belowground biomass, soil parameters, understorey PAR and wood physical properties in a 20-year-old Acacia mangium stand that was subjected to stand thinning 13 years ago. The results indicated that the impact of stand thinning on radial growth, mean tree basal area and mean tree volume was still persisting even 13 years after thinning. The highest response was from two-third thinning intensity (533 trees ha-1) followed by half thinned stand (800 trees ha-1). The tree level biomass followed the same pattern with the maximum aboveground (663.67 ±121.03 kg tree-1) and belowground (225.20 ±20.62 kg tree-1) biomass production recorded from the two-third thinning intensity. However on stand basis, the effect of thinning on volume and biomass did not show significant variation across treatments, probably due to the confounding effect of the higher number of trees in the low density stands. This trend was visible in stand carbon sequestration potential also. Even though two-third thinning intensity had maximum carbon sequestration at tree level (405.62 kg C tree-1), the stand level carbon sequestration did not vary with thinning treatments. Long-term effects of thinning had no influence on soil bulk density, pH, and available phosphorus and exchangeable potassium. However, all the thinning regimes registered significantly higher soil carbon stock compared to contiguous treeless control plot. Total nitrogen content also followed the same trend. Understorey Photosynthetically Active Radiation (PAR) availability observed in this study revealed reduced availability across all thinning regime except for the heavily thinned stand suggesting the possibility for intercropping. Thinning also had an impact on the root spread on a long term basis. The maximum spread of 2.84 m was recorded in the two-third thinning treatment which was significantly higher compared to other thinning intensities. Characterization of spatial root distribution pattern using logarithmic spiral trenching method suggested restricted root spread for the unthinned stand, while better root spread was observed with increased intensity of thinning. The results indicate that influence on thinning on wood physical properties are not significant across treatments. The wood density of 20-year-old A. mangium was 570.50 (kg m-3) albeit, was higher compared to mangium wood of relatively younger ages. Mean moisture content (37.51±3.1 %) and shrinkage values were relatively very low compared to the values reported from previous studies. Furthermore, the incidence of the soft core which was relatively less indicates better seasoning of the harvested wood. Understanding the long-term effects of stand management activities on productivity will help in taking better management decisions. On the whole, the study revealed that, since long term effects of thinning were significant for most of the productivity traits, thinning intensity regimes have a strong influence/bearing on stand management objectives.ThesisItem Open Access Performance of selected medicinal herbs under typical homegarden and pure coconut plantation(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2015) Niyas, P; KAU; Kunhamu, T KA field research was undertaken at Vellanikkara, Kerala to assess the understorey productivity of coconut and homegarden through intercropping with three selected herbaceous medicinal crops viz. Zingiber officinale (ginger), Curcuma longa L. (turmeric) and Kaempferia galangal L. (galangal). These landuse systems by virtue of spatial and temporal advantages offer good scope for integrating shade tolerant crops and thereby offer supplementary returns to the farmer. The biochemical changes in the understorey crops and the biophysical attributes influencing the productivity of the land management systems were studied. Additionally soil carbon sequestration in both the given land use systems and a treeless open plot was estimated. The intercrop growth considerably varied among the land use systems both in vegetative growth and rhizome yields. Growth observations at various sampling period revealed considerably higher plant heights of ginger and turmeric in shaded condition than treeless open. As regards leaf spread galangal performed well in the coconut garden followed by homegarden and treeless open. All the intercrops exhibited higher root length in treeless open plots, except galangal for which coconut was the best. Invariably root production was lowest in homegarden. Tiller production at final stages showed highest in treeless open. Contrary to the plant height growth trends, homegarden recorded lowest tiller production at final stages of sampling. Understorey productivity for ginger in terms of rhizome yield at final harvest followed the order treeless open (3.45 Mg ha-1), coconut (2.86 Mg ha-1), and homegarden (1.49 Mg ha-1). Turmeric rhizome production showed considerable variation with intercropping system with highest yield from open area (7.01 Mg ha-1) and the lowest from homegarden (1.77 Mg ha-1). Highest Galangal yields were reported in the treeless open (3.05) while homegarden represented lowest production (2.04 Mg ha-1). Understorey photosynthetically active radiation (PAR) transmittance presumed to have a cardinal influence on intercrop growth which was highest for coconut (37%) and lowest under homegarden (17%). Turmeric and galangal showed strong positive correlation with understorey PAR. Regression equation relating PAR with rhizome yields showed statistical soundness with high value of coefficient of determination (r2). Leaf Area Index varied between the homegarden and coconut considerably with higher value for homegarden (3.84) while the same for pure coconut plantation was considerably low (2.21). The oleoresin concentration in all the intercrops was found to be greatest in homegarden followed by coconut and treeless open. Soil physico-chemical attributes were assessed at periodic intervals in all the landuse system and results indicate overall better condition prevailed in the homegarden in terms of organic carbon content, soil bulk density, total N, available P and exchangeable K which however registered lowest values in the treeless open. Similar was the trend in soil carbon sequestration with homegarden giving higher values (67.45 Mg ha-1) followed by coconut (59.65 Mg ha-1) lowest by treeless open soil (55.1 Mg ha-1). Result converges to the generalisation that despite better soil physico-chemical attributes, understory productivity in the homegarden is by and large decided by the PAR availability. Hence there is need to develop stand structure that optimize the productivity in homegarden through judicious stand density regulation and tree management practices.ThesisItem Open Access Diversity, structure and standing stock of timber in the homegardens of Thrissur district, Kerala(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2017) Subu, R Unnithan; KAU; Kunhamu, T K
