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1996 - 19994
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Subject: Silviculture and Agroforestry × End date: 1999 × Start date: 1996 ×
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Now showing 1 - 4 of 4
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    ThesisItemOpen Access
    Nutritional defficiency symptoms of teak (Tectona grandis Linn. F )seedling
    (Department of Silviculture and Agroforestry, College of Forestry,Vellanikkara, 1997) Viju Varghese, KAU; Gopikumar, K
    Sand culture studies were conducted in College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur with an objective of inducing the symptoms of deficiency of various nutrient elements in seedlings of teak (Tectona grandis Linn.f.) grown in sand culture. The effects of nutrients viz., N,P,K, Mg,S,Zn and Mo on the growth, chlorophyll content and nutrient concentration of seedlings in the nursery were also studied. The results were finally confirmed by recovery studies by supplying the seedlings showing the symptoms of deficiency of various elements with complete nutrient solution. For the study, two months old seedlings of uniform growth were planted in containers filled with pure quartz sand and supplied with Hoagland No. 2 (1948) nutrient solution. The treatment solution was prepared by eliminating the desired nutrient from the complete Hoagland nutrient solution. The characteristic deficiency symptoms produced by seedlings due to the deficiency of various nutrient elements include leaf discolouration, necrosis, scorching, defoliation and growth stunting. The seedlings showing visual deficiency symptoms were also photographed. Seedlings that received complete nutrient solution were healthy with dark green foliage. Vegetative growth of the seedlings was also found to be affected due to the nutrient stress. All the fractions of chlorophyll ie; chlorophyll – A, chlorophyll – B total chlorophyll of the treatment seedlings particularly N deficient seedlings declined considerably during the study period. Visual deficiency symptoms of the nutrient elements also coincided with a corresponding reduction in foliar levels of the cocernrt element. There was remarkable improvement in the growth and recovery of the visual symptoms when the deficient element was again supplied to the seedlings through complete nutrient solution. The foliar nutrient content of these seedlings was also found to be improved significantly on application of complete nutrient solution.
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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
    Functional dynamics of an agrisilvicultural system involving coconut palms, Multipurpose trees and kacholam
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1997) Sureshkumar, S; KAU; Mohankumar, B
    A factorial experiment involving coconut (Cocos nucifera L.) and three multipurpose tree species (Ailanthus triphysa (Dennst.) Alston., Grevillea robusta A. Cunn. and Vateria indica L.) in two planting geometries (single and double hedge) was established in an existing coconut plantation (14 years old) at Vellanikkara in June, 1992. Kacholam (Kaempferia L.), a herbaceous medicinal plant was introduced in this trial as a floor crop in May 1995. Monocultures of coconut and kacholam were also maintained. Objectives of the study included evaluating suitability of interplanting multipurpose trees in coconut plantations, assessing the consequential changes in growth of multipurpose trees productivity of coconut and kacholam and inter alia characterise the above and below ground interactions between field and tree crop components. Coconut yield was not adversely affected by interplanting multipurpose trees until the multipurpose trees were about 4 years old. Multipurpose trees exhibited wide variations in their growth and crown characteristics. Consequently the light availability beneath the canopy was highly dependent on the multipurpose tree species. Availability of photosynthetically active radiation (PAR) was inversely proportional to the stand leaf area index. Available PAR ranged from 18-45 % and 22-45% of that in the open at 50 and 150 cm above ground level respectively. Planting geometry did not influence this parameter significantly. Kacholam grown in the open (sole crop) exhibited better growth as compared to kacholam grown in association with coconut and multipurpose trees. Nevertheless, rhizome yield (at final harvest) was comparable in all the situations. Tissue nutrient content of kacholam was also independent of multipurpose trees. The results suggests the moderate shade tolerant nature of kacholam, which can be highly useful in intercropping. However, no strong relationship could be established between light availability and rhizome yield. Multipurpose trees exhibited considerable root activity in the coconut rhizosphere, as evident from the data on 32P recovery. However, competition for nutrients between the two components was not evident, probably due to the juvenile nature (4 years old) of the multipurpose trees. Even at this stage, the three multipurpose trees exhibited discernable difference in foliar 32P activity. Cross-feeding of kacholam by coconut roots scavenging kacholam beds was noticed. Three to four years of tree growth did not alter the soil nutrient status very substantially. An increase in soil pH and available potassium was, however, observed. Nevertheless, kacholam cultivation resulted in a modest decline in soil nutrient status.
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    ThesisItemOpen Access
    Soil-plant nutritional status of Tectona grandis L.f. in relation to age and site quality
    (Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 1999) Vimal, M; KAU; Sudhakara, K
    A study was conducted at College of Forestry, Vellanikkara, KAU, during the period 1994-1996 to identify and assess the nutritional factors limiting productivity of teak plantations, of different age groups belonging to different site qualities, spread through out the State of Kerala. The study was aimed to find out the influence of nutrient status of soil and leaf on the growth as represented through volume and current annual increment in basal area per tree. Another objective was to find out the influence of soil characteristics like pH, organic carbon and nutrient contents on foliar nutrient concentration of teak. The leaf samples were analysed for N, P, K, Ca, Mg, Fe, Mn and Zn concentrations. The soil samples were analysed for pH, organic carbon, available P, total N and exchangeable K, Ca, Mg, Fe and Zn. The whole set of 300 trees was divided into three age groups as < = 20 years, > 20 and < = 40 years and > 40 years and stepwise regression was carried out by taking volume as dependent variable for each group separately. The resultant equations in stepwise regression were utilized to characterize the nature of response surface and to find the optimum levels of soil attributes and foliar nutrient elements. For analysing the relationship between soil attributes and foliar nutrient concentrations a technique called canonical correlation analysis was used. The relation between leaf nutrient status and tree volume was feeble in all the three age groups. In all the three age groups, the critical nutrient concentrations with respect to tree volume do not seem to be attained by the levels of nutrients available in the present data set, indicating a increase in tree volume by adequate supply of the appropriate nutrient elements. 2 The relation between tree growth and nutrient status of soil was stronger compared to the relation between the tree growth and nutrient status of soil. For the first two age group selected, the models were linear in nature. For the older plantations (Age > 40 years), almost 50 per cent of the variation in tree volume was explained by the soil nutrient levels. For this age group soil phosphorus had a quadratic term in the model and the point of maximal response for phosphorus was predicted at P = 26.66 ppm. The relationship between current annual increment in basal area per tree and nutrient status of leaves and soil was also linear. Age related change in current annual increment is positively modified by the level of soil nitrogen. To find out the relationship between the leaf attributes and soil attributes canonical correlation analysis was used. For the younger age group (age < = 20 years) soil organic carbon had a significant positive influence on leaf nitrogen and leaf potassium concentrations while it had a negative effect on leaf Fe and leaf Mg concentrations. Also significant positive correlation was seen between leaf Ca and soil Ca for all the age groups. The canonical correlation analysis showed that as the age of the plantations increases and the canopy closure occurs, the leaf nutrient contents influence the soil fertility attributes to a greater extend due to the effect of litter fall.