PG Thesis
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/2
Browse
7 results
Search Results
Item Biomass production, root distribution and yield responses of green leaf manure trees on wetland paddy bunds(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2024-02-28) Aravind, R.; Asha,K RajIndia's agriculture sector, which accounts for 18.2 per cent of the GDP and employs nearly half of the workforce, is heavily dependent on imported fertilizers, placing a significant fiscal burden on the economy. To mitigate this dependency and enhance soil fertility, the practice of green leaf manuring offers a sustainable solution. Traditionally, green leaf manuring in paddy fields was a popular practise among Kerala paddy farmers by gathering green leaves from nearby trees, but changes in cropping systems, reduced tree availability, land constraints, and labour shortages hindered this practice. Planting green leaf manure trees directly on bunds can address these issues. This study assesses the growth and green biomass production of selected green leaf manure tree species on wetland paddy bunds, as well as root distribution patterns and interactions with adjacent paddy crops. This study was conducted at paddy fields of State Seed Farm, Mannuthy, Kerala, on existing bund-grown trees comprising of nine different species such as Sesbania grandiflora, Terminalia arjuna, Gliricidia sepium, Cassia siamea, Gmelina arborea, Calliandra calothyrsus, Morus indica, Neolamarckia cadamba, and Cajanus cajan. The study was designed using a Randomized Block Design (RBD) with three replications. Trees were planted at 1-meter spacing and maintained as hedgerows. Growth, yield and root distribution parameters were measured during the second year after establishment. The results revealed significant variation in growth and green biomass production among the bund-grown tree species. N. cadamba excelled in collar diameter, while Morus indica underperformed. C. cajan exhibited complete mortality after one-and-half years, resulting in a survival percentage of zero by the end of the study. N. cadamba and T. arjuna showed notably high annual green biomass yields, at 7.03 kg and 4.54 kg per tree, with survival rates of 96 and 90 per cent, respectively. Other species produced moderate levels of green biomass, with the exception of G. arborea and M. indica, which yielded minimal to no biomass. Root distribution analysis revealed that T. arjuna demonstrated a pronounced rooting depth of 106 cm and a taproot length of 75.67 cm. The maximum lateral root spread was observed in N. cadamba (1.96 m) and G. arborea (1.94 m), both exhibiting a high number of roots with substantial diameter, enhancing bund stability and resource utilization. Root angle analysis showed a preference for lateral spread in G. sepium (82.62°) and C. siamea (80.57°). Conversely, M. indica and C. cajan underperformed across most of the root parameters. 124 Paddy beneath S. grandiflora showed highest grain yield of 5.31 Mg ha-1 within 1m distance from the tree and 5.22 Mg ha-1 at 1-2 m, which indicates the complementary interactions. Moreover, paddy yield under all other tree species were comparable to the control plot except M. indica, T. arjuna and C. calothyrsus, which exhibited competitive interactions with paddy up to a distance of 2 m from the tree base. Paddy nutrient content analysis revealed that paddy fields adjacent to C. cajan exhibited higher concentrations of nitrogen, phosphorus, and potassium compared to other treatments. Soil pH significantly influenced nutrient availability, with C. cajan showing the highest pH (6.06) and C. siamea the lowest (4.31). Electrical conductivity (EC) was highest in treeless bunds (0.17 dS m-¹) and T. arjuna (0.13 dS m-¹), while C. cajan and N. cadamba exhibited lower EC (0.06 dS m-¹). Soil organic carbon (SOC) was highest in open fields (1.21%). Soil beneath T. arjuna had the highest nitrogen (172.20 kg ha-¹) and potassium (41.44 kg ha-¹), while C. cajan had the highest phosphorus (62.09 kg ha-¹). In conclusion, the study highlights N. cadamba and T. arjuna as the most productive and adaptable species, demonstrating superior growth and green biomass production on wetland paddy bunds. S. grandiflora and C. siamea also produced considerable green biomass with minimal interactions with paddy crops. T. arjuna and M. indica were associated with reduced paddy yields, likely due to competition and pest pressures. G. sepium is also a potential species, however, it may perform optimally under conditions that include seedling planting and specific management practices. However, long-term studies are required to get more concluding results on crop interactions and soil fertility changesItem Biomass production, root distribution and yield responses of green leaf manure trees on wetland paddy bunds(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2024-02-28) Aravind, R.; Asha K RajIndia's agriculture sector, which accounts for 18.2 per cent of the GDP and employs nearly half of the workforce, is heavily dependent on imported fertilizers, placing a significant fiscal burden on the economy. To mitigate this dependency and enhance soil fertility, the practice of green leaf manuring offers a sustainable solution. Traditionally, green leaf manuring in paddy fields was a popular practise among Kerala paddy farmers by gathering green leaves from nearby trees, but changes in cropping systems, reduced tree availability, land constraints, and labour shortages hindered this practice. Planting green leaf manure trees directly on bunds can address these issues. This study assesses the growth and green biomass production of selected green leaf manure tree species on wetland paddy bunds, as well as root distribution patterns and interactions with adjacent paddy crops. This study was conducted at paddy fields of State Seed Farm, Mannuthy, Kerala, on existing bund-grown trees comprising of nine different species such as Sesbania grandiflora, Terminalia arjuna, Gliricidia sepium, Cassia siamea, Gmelina arborea, Calliandra calothyrsus, Morus indica, Neolamarckia cadamba, and Cajanus cajan. The study was designed using a Randomized Block Design (RBD) with three replications. Trees were planted at 1-meter spacing and maintained as hedgerows. Growth, yield and root distribution parameters were measured during the second year after establishment. The results revealed significant variation in growth and green biomass production among the bund-grown tree species. N. cadamba excelled in collar diameter, while Morus indica underperformed. C. cajan exhibited complete mortality after one-and-half years, resulting in a survival percentage of zero by the end of the study. N. cadamba and T. arjuna showed notably high annual green biomass yields, at 7.03 kg and 4.54 kg per tree, with survival rates of 96 and 90 per cent, respectively. Other species produced moderate levels of green biomass, with the exception of G. arborea and M. indica, which yielded minimal to no biomass. Root distribution analysis revealed that T. arjuna demonstrated a pronounced rooting depth of 106 cm and a taproot length of 75.67 cm. The maximum lateral root spread was observed in N. cadamba (1.96 m) and G. arborea (1.94 m), both exhibiting a high number of roots with substantial diameter, enhancing bund stability and resource utilization. Root angle analysis showed a preference for lateral spread in G. sepium (82.62°) and C. siamea (80.57°). Conversely, M. indica and C. cajan underperformed across most of the root parameters. 124 Paddy beneath S. grandiflora showed highest grain yield of 5.31 Mg ha-1 within 1m distance from the tree and 5.22 Mg ha-1 at 1-2 m, which indicates the complementary interactions. Moreover, paddy yield under all other tree species were comparable to the control plot except M. indica, T. arjuna and C. calothyrsus, which exhibited competitive interactions with paddy up to a distance of 2 m from the tree base. Paddy nutrient content analysis revealed that paddy fields adjacent to C. cajan exhibited higher concentrations of nitrogen, phosphorus, and potassium compared to other treatments. Soil pH significantly influenced nutrient availability, with C. cajan showing the highest pH (6.06) and C. siamea the lowest (4.31). Electrical conductivity (EC) was highest in treeless bunds (0.17 dS m-¹) and T. arjuna (0.13 dS m-¹), while C. cajan and N. cadamba exhibited lower EC (0.06 dS m-¹). Soil organic carbon (SOC) was highest in open fields (1.21%). Soil beneath T. arjuna had the highest nitrogen (172.20 kg ha-¹) and potassium (41.44 kg ha-¹), while C. cajan had the highest phosphorus (62.09 kg ha-¹). In conclusion, the study highlights N. cadamba and T. arjuna as the most productive and adaptable species, demonstrating superior growth and green biomass production on wetland paddy bunds. S. grandiflora and C. siamea also produced considerable green biomass with minimal interactions with paddy crops. T. arjuna and M. indica were associated with reduced paddy yields, likely due to competition and pest pressures. G. sepium is also a potential species, however, it may perform optimally under conditions that include seedling planting and specific management practices. However, long-term studies are required to get more concluding results on crop interactions and soil fertility changesItem Growth and productivity as function of site quality and age in teak plantations of Nilambur, Kerala(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2021) Sankar Thampuran, M V; Kunhamu, T KTeak has been one among the principal timber species widely used across the world due to its matchless combination of qualities. Kerala has around 76,710 ha of pure teak and 14,440 ha of teak with softwood plantation making up 49.08 and 9.24 per cent respectively of the total plantation area in the state. Despite having the largest share of plantations under teak, the productivity of teak plantations of Kerala are under serious decline and has been a matter of concern in the scientific parlance. Evidences suggest that even in Nilambur, the celebrated land of teak, there has been large scale decline in productivity of teak plantations. However, quantitative aspects of the productivity of teak and the drivers of changes especially in the best teak growing region in Kerala such as Nilambur, is lacking. In this backdrop, a field study entitled “Growth and productivity as function of site quality and age in teak plantations of Nilambur, Kerala” was conducted in selected plantations from Nilambur North and Nilambur South Forest Divisions. The plantations were selected based on the information available from Kerala Forest Department on their age and site quality. Four site qualities (SQ I, SQ II, SQ III and SQ IV) and five age classes (10-20, 20-30, 30-40, 40-50 and 50+) were considered for the study forming a total of 20 plantations (4 site qualities x 5 age classes = 20 plantations). Five sample plots, each of size 24m x 24m were laid out randomly in each of the selected plantations and parameters like total tree height, bole height, diameter at breast height, diameter at crown point and crown width were measured in the field. Also, soil sampling was done in four plantations of different site qualities falling in the mature age class of 40-50. For this, 1 m deep soil pits were dug, one each inside the plantation and in the respective contiguous treeless open. Sampling was done in five depth intervals (0-20, 20-40, 40-60, 60- 80 and 80-100 cm). Thus, a total of 120 samples of soil were collected for analysis. The collected soil was analysed for physical properties like bulk density and particle size distribution/ texture and chemical properties like pH, total Nitrogen, organic Carbon content, available Phosphorus and exchangeable Potassium following standard procedures. 122 The results showed that among the plantations studied in Nilambur, the SQ I plantations showed dominance in all growth parameters of teak while a predictable pattern of change was lacking across the subsequent site qualities. There was large heterogeneity among the plantations in terms of management that had a confounding effect on the potential exploitation of the site resources for optimal growth of teak. Many of the plantations had high density of invaded miscellaneous trees which have increased the effective density and seriously affected the growth of teak. The density of miscellaneous trees varied from 0 to 694 trees per hectare among the studied plantations. The competition with miscellaneous species has created large scale variability within each stand in growth attributes. Normal distribution of diameter classes was observable in the plantations studied due to high effective density. Stand density being a critical factor that decide productivity and product quality in teak plantations, the observed variability in productivity could be attributed to poor adherence to proper density regulation. Also, the productivity of the plantations has been considerably influenced by poor adherence to timely plantation management practices. The Mean Annual Increment varied from 0.56 to 8.70 m3ha-1yr-1 among all the plantations studied. On comparing with the All-India yield table for teak, the plantations showed growth and productivity estimates that were quite different from their assigned site quality. In the age class 40-50, the SQ I plantation showed a height that was corresponding to SQ III according to the yield table, while the SQ IV plantation height corresponded to the SQ II. All the observed soil parameters with in the experimental plots were well within the range required for the optimal growth of teak. However, except for SQ1, we could not observe any predictable change in soil properties across the remaining site qualities. The Bulk density of soil increased with depth, both inside and outside the plantations. The rate of increase of bulk density was higher in the treeless open areas compared to the plantations. Th soil texture remained as sandy loam or loamy sand for all the analysed soil samples. The soil pH varied from 5.17 to 5.98 between the soil samples that were analysed. The organic Carbon content in various layers of plantation soil varied from 0.58 to 2.07 %. Total Nitrogen varied from 0.077 to 123 0.223 %. Available Phosphorus varied from 2.10 to 17.33 kgha-1. Exchangeable potassium varied from 51.82 to 488.30 kgha-1. Attempts to relate the soil properties with the site productivity could not derive meaningful correlations suggesting that the productivity decline might be an effect of poor management rather than depletion of nutrient status. The study suggests that there is an urgent need to revisit and reassess the site quality of the plantations in Nilambur and to give utmost concern for adhering to scientific stand management in timebound manner for deriving optimal productivity from teak plantations of Nilambur.Item Technology needs and risks assessment of specialised homegardens(Department of Agricultural Extension, College of Agriculture, Vellayani, 2018) Sreelakshmi, C; Allan ThomasItem Biomass production and nutrient accumulation in an age series of caesalpinia sappan Linn. plantations(Department of Forest Management and Utilisation, College of Forestry, Vellanikkara, 2006) Imrose Elias Navas, E; Vidyasagaran, KThe present study was conducted at College of Forestry, Kerala Agricultural University, Vellanikkara on biomass production and nutrient accumulation in an age series (5, 6 and 7) of Caesalpinia sappan plantations in three districts of Kerala. The study reveals that diameter, height, biomass, productivity and volume increased with increasing age. The above ground biomass and biomass components also increased with increasing ages. The above ground biomass produced was 23.81 t ha-1 at 5 year, 37.80 t ha-1 at 6 year and 44.36 t ha-1 at 7 year. The productivity at age 5 year was 4.77 t ha-1yr-1, at age 6 year 6.30 t ha-1 yr-1 and at age 7 year was 6.34 t ha-1 yr-1. The increase of the productivity between 6 and 7 years were very low (0.04 t ha-1yr-1), which indicated that no further increase in the productivity of the trees. It highlights that a levelling off the productivity beyond 6 year. This consideration suggests 6 year as the optimum harvesting period of C. sappan. The percentage contribution of various components to above ground biomass was in the order: bole > branch > twig > fruit > leaves> bark. The biomass components were also showed an increasing trend. The prediction equations were prepared for above ground biomass as well as biomass components with respect to dbh and height. Even though some equations were proved more fit with combination of dbh and height, R2 value and Furnival index were relatively similar to equations with dbh alone could not be selected, it is difficult to measure height of the standing trees with definite accuracy. Hence, equations with dbh alone were selected for predicting the biomass. With respect to the dbh alone as independent variable, the total above ground biomass, the best fit equation was W = b0 +b1 D+ b2 D2. In leaves also this model proves as best fit. The components like bole, bark, branch and fruit, the best fitted equation was ln W =b0 + b1 ln D. But in twig, it was W=b0 + b1 D2. Weight table prepared for bole (UB) and total above ground biomass based on the best fit equation using diameter at breast height The nutrient concentration was increased with increasing age except in bole and branches. Concentration in bole and branches increased from 5 to 6 year and decreased from 6 to 7 year. Leaves had the maximum concentration of the nutrients and bole the lowest. The nutrient accumulation of the above ground biomass as well as biomass components increased with the increasing age of plantation. The maximum nutrients accumulated in bole and minimum in bark. Among the nutrients, N accumulated maximum followed by K and P. Nutrient use efficiency increased with increasing ages. The maximum nutrient use efficiency observed for P followed by K and N. It was found to be maximum in bole and minimum in leaf.Item Performance of selected medicinal herbs under typical homegarden and pure coconut plantation(Department of Silviculture and Agroforestry, College of Forestry, Vellanikkara, 2015) Niyas, P; Kunhamu, T KItem 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; Gopikumar, KA 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.