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Theses

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1994 - 19964
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Subject: Silviculture and Agroforestry × Author: KAU × End date: 1996 × Start date: 1990 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Biomass production and root distribution pattern of selected fast growing multi-purpose tree species
    (Department of Silviculture and Agroforestry, College of Forestry,Vellanikkara, 1994) Jamaludheen, V; KAU; Mohankumar, B
    A randomized block design experiment involving nine fast growing multi – purpose trees (Acacia auriculiformis A. Cunn. ex Benth., Casuarina equisetifolia J.R. & G Forst., Leucaena leucocephala (Lamk.) de wit. Var. K 8, Ailanthus triphysa (Dennst.) Alston, Emblica officinalis Gaertn, Artocarpus heterophyllus Lamk., Pterocarpus marsupium Roxb., Paraserianthes falcataria (L.) Neilson and Artocarpus hirsutus Lamk.) Initiated during June, 1985 was used for the present investigations. The objectives of the study included quantifying the biomass production potential of nine selected fast growing multi-purpose tree species grown under short rotation intensive cultural systems; characterising the root distribution pattern of these trees and also elucidating the extent of nutrient loss through harvest, besides characterising litter dynamics. Acacia and paraserianthes recorded the highest growth rates in terms of height, radial growth and biomass yield. Biomass production decreased in the order: Acacia > Paraserianthes > Casuarina > A. heterophullus > Emblica Pterocarpus > A. hisrsutus > Ailanthus > Leucaena. The most important component of total biomass undoubtedly, was the bole while foliage contributed least to biomass yield. Nevertheless foliage, in general registered the highest N, and K contents. Among the species, Leucaena had the highest N concentration followed by Paraserianthes and Pterocarpus. For P and K concentrations, Pterocarpus and A. hirsutus registered the highest concentration. A one – to – one correspondence between nutrient accumulation and biomass yield was however, lacking because of wide variations in elemental concentrations among species and also among tissue types. Bole fractions, in general, did not account for more than 50 % of total nutrient export from site. Altering the rate of nutrient removal in products is one of the most important design criteria in planning for sustainable plantion. N-fixing tree plots generally had a higher soil N status. Casuarina, Emblica and Pterocarpus plots were having higher P levels. Acacia, Paraserianthes and A. hisrsutus plots registered markedly higher K level. The amount of litterfall was maximum for Acacia and the minimum for Pterocarpus. Litterfall also followed a unimodal distribution pattern with a distinct peak during the November – January period and the period of lean fall was during May-August. Litter dynamics accounted for bulk of the nutrient inputs into the system. The retranslocation of mineral nutrients from senescing leaves to younger leaves and /or other tissues prior to abscission was obvious. Leucaena, Paraserianthes, Pterocarpus, Acacia, Alinathus and Emblica formed examples of high (> 1.5%) detrital N content. Generally the wet period (June – August) was characterised by increased concentration of N in litter. Litter P did not follow a consistent pattern with respect to seasons. However, a characteristic decline in litter K concentration was noticed during the rainy season. Mass disappearance of litter samples followed a negative expontential relationship. Leucaena litter, having the highest initial N content, decomposed compeletely in the shortest period (9 months). Root system studies suggest that A. hetrophyllus, Emblica and Paraserianthes are perhaps unsuitable for intensive mixing and close planting in agroforestry as they possess shallow and highly spreading root system. Ailanthus is perhaps a better candidate species for the above purpose as it possess relatively lower lateral root spread and at the same time having a deep tap root system. Root activity paatern of Artocarpus hisrsutus revealed that more than 75% of fine roots responsible for water nutrient absorption is concentrated in the 75 cm radius around the base of the tree. Recovery of 32P declined as depth of application increased. The combination of lowest lateral distance (75 cm) and depth (30 cm) accounted for more than 30% root activity.
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    ThesisItemOpen Access
    Viability of hopea parviffora seeds with reference to temperature , medium of storage and microencapsulation techniques
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1996) Sunilkumar, K K; KAU; Sudhakara, K
    A detailed study was conducted at College of Forestry, Kerala Agricultural university, Vellanikkara, Thrissur, Kerala during 1994 – 95 to study the effect of temperature, storage medium, fungicide and microencapsulation of zygotic embryo (synthetic seed) on the storage behaviour of Hopea parviflora seeds. Storing the dewinged seeds with a moisture content below 30 per cent resulted in rapid decline in seed viability due to dehydration injuries irrespective of storage temperature. Sand and neemcake was inappropriate as a storage medium because sand favoured early germination of the seeds in storage condition itself and neemcake caused severe desiccation injuries. Storing fungicide treated winged seeds collected just before natural seedsheding, at 100 C retained high germination percentage upto 40 days. Sythetic seeds were also successfully stored up to 1 month at 100C without significant reduction in germination percentage. Two ppm and three ppm ABA was observed to be helpful for maintaining higher germination percentage of synthetic seeds during storage.
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    ThesisItemOpen Access
    Nutrient content and decomposition of leaf litter of Acacia mangium Willd as affected by season and field conditions
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1995) Ramakrishna, Hegde; KAU; Gopikumar, K
    A detailed experiment was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, during the period from 1993 to 1995 to study the nutrient content and pattern of leaf litter decomposition of Acacia mangium Wild. During south west monsoon and north east monsoon seasons. The experiment was conducted both in home garden and open area. The rate of decomposition was faster in all the study situations. The initial nitrogen, lignin, C:N ratio and lignin : nitrogen ratio of leaf litter were found to exert profound influence on the rate of decomposition. The decomposition rate was found to be a function of time, soil moisture and soil temperature. The nutrient release pattern in almost all cases followed a characteristic biphasic model with an initial rapid phase followed by a slower latter phase. Among the different nutrients, potassium showed a faster rate of mineralisation in most of the situations while calcium and nitrogen mineralised slowly. Among the several mathematical models tried to predict the absolute amount of nutrients in the residual mass, the second order hyperbolic function was found to be good fit in most of the cases. Though the PH was not altered significantly by the decomposing litter mass, the content of most of the nutrient elements is found to be drastically influenced.
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    ThesisItemOpen Access
    Nutrient content and decomposition of leaf biomass of selected woody tree species
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1994) Kunhamu, T K; KAU; Gopikumar, K
    A detailed study was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur, Kerala during 1992-94 to compare the rate of decomposition and nutrient release pattern of leaf biomass of five forest tree species namely, Schleichera oleosa (Lour.) Oken, Pongamia pinnata (L.) Pierre, Macaranga peltata, (Roxb) M.–A., Terminalisa paniculata Roth and Bridelia retusa (L.) spreng. The experiment was laid out in a typical home Garden. Generally, all the species under study showed a faster rate of leaf biomass decomposition. Among the various species tested, B. retusa and T. paniculata showed faster rates of leaf biomass decomposition while P. pinnata exhibited relatively a slower rate. The initial leaf nitrogen content and C:N ratio could not establish a direct relationship with rate of decomposition. However, in all the species, lignin content was found to exert a profound influence on mass loss patterns. All the species showed a faster mineralisation of nutrients in accordance with the mass loss pattern. Among the nutrients, potassium followed a faster rate of mineralisation. A relatively good trend for N mineralisation also has been reported for M. peltata, T. paniculata and B. retusa during the course of the study. Generally, Ca, Mg and S exhibited lower rates of mineralisation. T. paniculata and B. retusa followed an efficient release pattern for all the nutrients while P. pinnata showed slower rates of mineralisation with regard to most of the nutrients.