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Subject: Agricultural Meteorology × Author: KAU × End date: 2019 × Start date: 2019 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Carbon sequestration potential of selected seaweeds of Thikkodi, Kerala
    (Academy of Climate Change Education and Research, Vellanikkara, 2019) Saranya, M S; KAU; Vinod, K
    The coastal blue carbon is the carbon sequestered by mangrove, tidal marshes, seagrasses and macroalgae which account for less than 0.5% of the seabed. Unlike, other blue carbon sectors (mangroves, tidal marshes and seagrasses), the macroalgae do not have sedimentary substratum. The macroalgae are commonly known as seaweeds. The ‘seaweeds’ as the name suggest is not an unwanted plant or weed. It has an important role in the marine ecosystem by acting as a sink for carbon emissions. The present study is based on the carbon sequestration potential of selected seaweeds of Thikkodi coast, Kerala. The state of Kerala has a long coastline of about 580 km, ranking only third among all the maritime states of the country. Some of these coastline stretches are pegged with areas of seaweed resources. The Thikkodi coast (11º28’30.8” N, 75º37’04.5”E) in the Kozhikode district of Kerala is well known for its rocky intertidal coast with a luxuriant growth of seaweeds of diverse species. An extensive study of seaweeds and their species diversity was carried out for a period of one year from September 2018 to August 2019 along the Thikkodi coast of Kerala. A total of 40 species of seaweeds were recorded which belonged to 23 genera, 18 families and 14 orders. A total of 19 species belonged to Chlorophyta, while 12 species belonged to Rhodophyta and 9 species belonged to Phaeophyta. The distribution and seasonal abundance of different species along the Thikkodi coast was also studied. The biodiversity indices were studied using PRIMER (Plymouth Routines in Multivariate Ecological Research). The biodiversity indices such as Shannon-Wiener diversity (H’), Pielou’s evenness (J’), Margalef species richness (d) were calculated. The seaweeds collected from Thikkodi coast were used to carry out the carbon sequestration potential studies. While comparing the three zones, the highest value of species richness (S) was obtained in zone 1 (S=14.00), followed by zone 2 (S=8.75) and zone 3 (S=7.08). The Margalef’s index (d) which incorporates the number of individuals (N) and species (S) was the highest in zone 1 (2.10), while it was minimum in zone 3 (1.08). The equitability or individuals among the different species showed much variation between the zones and the values ranged from 0.67 (zone 2) to 0.77 (zone 1). In the present study, the Shannon Wiener Index (H’) showed wide variation between the zones ranging from the lowest value of 1.33 (zone 3) to the highest value of 1.99 (zone 1). The Simpson Index (1-Lambda’) showed variations in values ranging from 0.66 (zone 3) to 0.82 (zone 1). The experiments were conducted on selected seaweeds particularly Gracilaria corticata, Caulerpa scalpelliformis and Caulerpa peltata. Carbon dioxide was dissolved in seawater at different concentrations using a soda maker by adjusting the fizz. After determining the initial CO2, the seaweeds were incubated in 125ml light bottles under a water column of 50-60cm for 2 hours. The initial CO2 concentration (mg/l) and the CO2 utilization were examined by titrating the seawater against 0.5N Sodium hydroxide solution using Phenolphthalein indicator. The Gross Primary Production (GPP) and Net Primary Production (NPP) were also estimated. For Gracilaria corticata, the utilization efficiency increased from 33.33% to 83.33% in lower CO2 concentration of 26.4mg/l and 79.2mg/l respectively. For Caulerpa scalpelliformis, the utilization efficiency increased from 25% to 42.86% in a lower CO2 concentration of 17.6mg/l and 30.8mg/l respectively. For Caulerpa peltata, the utilization efficiency increased from 66.67% to 75% in a lower CO2 concentration of 13.2mg/l and 35.2 mg/l respectively. When the concentration of CO2was increased beyond a threshold level, the CO2 utilization efficiency decreases and cease down to zero .Same is the case for productivity. Therefore the study implies that the carbon sequestration potential of different species of seaweeds varies. The macroalgae have a greater potential to act as carbon sink and based on the sequestration potential of seaweeds, selection of different species of seaweeds can be made possible for developing Seaweed Aquaculture Beds (SABs). The SABs provide important structure in coastal ecosystem and play an incredible role in climate change mitigation aspects.
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    ThesisItemOpen Access
    Study the impact of abiotic stress on photosynthetic potential of tropical tuber crops under elevated CO2
    (Academy of Climate Change Education and Research, Vellanikkara, 2019) Ancy, P; KAU; Nameer, P O
    Climate change and agriculture are interconnected processes, both of which take place on a universal scale. Global warming is expected to have significant impacts on agriculture. Most of the studies reported a positive impact in photosynthetic rate of C3 plants due to eCO2. However other players of climate change such as drought and rising temperature can harmfully affect crops. Cassava and sweet potato are two major tropical root crops grown in India. The main objective of the present study was to figure out the impact of adverse conditions of climate change such as water deficit stress and high temperature stress on photosynthetic potential of tropical tuber crops under elevated CO2 and there by identify crop/varieties suitable for changing climate conditions. The study was conducted during the period of October 2018 to July 2019 on four contrasting cassava and four contrasting sweet potato varieties. Observations on photosynthetic parameters viz., the net photosynthetic rate (Pn), stomatal conductance (gs) transpiration and sub-stomatal/intercellular CO2 concentration (Ci) were recorded using a LI6400 portable photosynthesis system, LI-COR Inc, Lincoln, USA. Elevated CO2 have positive effects on photosynthetic parameters under WDS free as well as WDS conditions in cassava as well as sweet potato. Even though WDS reduces photosynthetic rate, eCO2 could sustain greater Pn rate than ambient CO2 under WDS. Under eCO2 rising temperature can benefit cassava and sweet potato only under WDS free conditions. For cassava Pn was not significantly affected by temperatures. For sweet potato Pn significantly increased with rise in temperature. It indicates that increasing temperature is not a limiting factor for cassava and sweet potato, but beneficial for them under WDS free conditions. Responses of cassava and sweet potato to WDS and rising temperature are also influenced by the variety. Cassava variety Sree Athulya responses well to eCO2 as well as to rising temperature under WDS free conditions. Cassava variety Sree Vijaya can perform well under WDS compared to other varieties. Sweet potato variety Sree Arun exhibits higher Pn under WDS free conditions. Bhu Krishna and Kanhangad had high Pn under WDS as well as at higher temperature. From this study it can be concluded that tropical root and tuber crops especially cassava and sweet potato have a great potential for better adaptation at elevated CO2 environment under adverse climate conditions such as water deficit stress and increasing temperature. They can become crops providing food security for future environment under climate change.
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    ThesisItemOpen Access
    Crop weather relationship studies in finger millet (Eleusine coracana (L.) Gaertn) in central zone of Kerala
    (Department of Agriculture Meteorology, College of Horticulture, Vellanikkara, 2019) Anunayana John, T; KAU; Ajithkumar, B
    Finger millet (Eleusine coracana (L.) Gaertn) is an important food crop next to rice, wheat and maize. The crop is native to Africa. Finger-millet is capable to withstand three stresses such as warming stress, water stress and nutrition stress, so it is called as Climate Change Compliant Crop (CCCC). These attributes combine to make finger millet a suitable crop for ensuring food security in drought prone areas of the countries. The present study was done to estimate the crop weather relationship in finger millet (var : GPU-28) in central zone of Kerala and to identify the ideal date of planting and best crop establishment method during 2018. The field experiment was conducted at experimental field of Instructional Farm, College of Horticulture during the kharif season of 2018. Split plot design was adopted with five dates of planting viz., May 15th, June 1st, June 15th, July 1st and July 15th as the main plot treatments and three planting methods viz., broadcasting, dibbling and transplanting as the sub plot treatments with number of replications as three. Considering the weather observations, the daily observations of weather recorded during the crop period like maximum, minimum and mean temperature, rainfall and relative humidity showed considerable variations especially during the mid-growth period. Heat units like Growing Degree Days (GDD), Heliothermal Units HTU) and Photothermal Units (PTU) were also calculated for the crop growth period. Growth and yield attributes like plant height, dry matter accumulation, number of ear heads, finger number per ear head, finger length, thousand grain weight, grain yield, straw yield, harvest index and the duration of different phenophases were also noted. Growth indices such as crop growth rate and relative growth rate were worked out to analyze the growth and development of the crop. Micrometeorological and weeds observations were also made. Correlation analysis was carried out using the weather parameters, yield and phenological data to estimate the crop weather relationship in finger millet. The results shows that maximum temperature was showing a negative correlation, while relative humidity, vapour pressure deficit and rainfall was showing positive correlation in most of the yield and yield contributing factors. Considering the micro meteorological observations, June 1st planting showed the highest values for both forenoon and afternoon soil temperature. Highest soil moisture was observed in broadcasting method of planting at 15cm depth and it did not show any considerable variations with respect to date of planting. Weed intensity and dry weight was shown higher during the dibbling method of planting. ABSTRACT Plant height was found to be higher for dibbling method of planting at 60 days after sowing and May 15th planting showed the higher values which was on par with June 15th planting. Dates of planting had significant effect on the dry matter accumulation which showed higher values for June 15th planting which was on par with June 1st planting at harvest in broadcasting method. Crop growth rate showed an increasing trend during the vegetative phases and there after followed a decreasing trend up to harvest, while relative growth rate showed a gradual decreasing trend from mid-growth period. Duration of phenophases was similar for both broadcasting and dibbling method, while transplanting took comparatively more days to attain each stages. Duration also showed a decreasing trend with delay in date of planting. Heat indices like GDD and PTU followed a decreasing trend with delay in date of planting which indicates their positive impact on the growth and yield performance of finger millet. Considering the yield attributes like number of ear heads m-2, it showed higher values for transplanting method in May 15th planting. Finger number per ear head was higher for June 1st planting which was on par with both May 15th and June 15th planting. Highest finger number per ear head was attained for transplanting method which was on par with dibbling method of planting. Finger length showed the highest value in May 15th planting which was on par with June 1st planting. Date of planting showed significant effect on the straw yield as it was higher in May 15th planting and was lower in July 1st planting which was on par with July 15th planting. Harvest index attained higher values for July 1st planting which was on par with July 15th and June 1st planting. Interaction effect of the treatment combination of May 15th planting with transplanting method attained the highest grain yield (2833.3 kg ha-1) compared to other methods. Assessment of cost of cultivation revealed dibbling method showed highest value while it was lowest in broadcasting method. But the B:C ratio was highest in transplanting and the lowest was observed in dibbling method of planting. This revealed that transplanting method not only encourages yield production, but also economically feasible compared to broadcasting and dibbling methods. So the present investigation on the crop weather relationship in finger millet suggested that the positive contribution of various weather and micrometeorological parameters like relative humidity, vapour pressure deficit, rainfall, forenoon and afternoon soil temperature etc. and the reduced maximum temperature and temperature range which increased the production of number of ear heads, finger number per ear head, increased finger length, straw yield etc. This ultimately leads to increased grain yield in May 15th and June 1st date of planting. In case of the three planting methods, studies suggested that transplanting can be considered as best establishment method for finger millet cultivation in central zone of Kerala.
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    ThesisItemOpen Access
    Crop weather relationship of rice varieties under different growing environments
    (Department of Agricultural Meteorology, College of Horticulture, Vellanikkara, 2019) Haritharaj, S; KAU; Ajithkumar, B
    In India, rice production is an important part of the national economy. India is the second largest producer in the world with approximately 43 million hectares planted area, accounting for 22% of the total rice production in this world. World’s leading rice exporter is India, marketing about 12.5 million metric tonnes in 2018-19. Rice is grown in rainfed areas with heavy annual rainfall. Therefore it is fundamentally considered as a kharif crop. But its production mainly depends up on weather prevailing in that area. Weather has a profound influence on growth, development and yields of crop; on the incidence of pests and diseases; on water needs; and on fertilizer requirements. The present experiment was aimed to study the crop weather relationship of rice varieties under different growing environments and to validate different crop weather models for rice varieties including statistical models and crop simulation model (DSSAT CERES-Rice model). Two varieties of rice, Jyothi and Jaya were raised at Agricultural Research Station, Mannuthy by adopting split plot design. Five planting dates such as June 5th, June 20th, July 5th, July 20th and August 5th were used as main plot treatments and the two varieties were used as sub plot treatments. The replication number used for this experiment was four. During the field experiment, daily weather data were collected like maximum temperature, minimum temperature, relative humidity, rainfall, bright sunshine hours, wind speed and evaporation. Biometric observations like plant height, leaf area, dry matter accumulation, number of tillers per unit area, number of panicles per unit area, number of spikelets per panicle, number of filled grains per panicle, thousand grain weight, straw yield and grain yield were observed. Duration of different phenophases and physiological observations such as leaf area index, net assimilation rate, leaf area duration and crop growth rate were also calculated. Pests and diseases were noticed during different growing conditions. Considerable variation among weather variables were noticed during the field experiment. Plant height was higher for Jyothi compared to Jaya and it showed variation among different planting dates. Maximum dry matter accumulation was recorded during 75 days after planting and it exhibited a decreasing trend with delayed planting in both the varieties. Number of spikelets per panicle, number of filled grains per panicle, thousand grain weight and straw yield were found to be decreasing as the planting date was delayed. Highest grain yield (4698 kg ha-1) was observed in Jyothi during June 20th planting whereas, June 5th planting showed maximum grain yield (5527 kg ha-1) in Jaya. Because, continuous morning rainfall during flowering stage of Jyothi reduced its yield in June 5th planting (3021.25 kg ha-1). Maximum duration was observed during June 20th planting in Jyothi (129 days) and Jaya (139 days). Total duration was less for August 5th plantings in both the varieties (121 and 129 days for Jyothi and Jaya respectively). Leaf area index and leaf area duration were more during 75 days after planting for both the varieties and leaf area duration showed a maximum value during 60-75 days after planting for both the varieties. In general, crop growth rate of both Jyothi and Jaya was found to be more during 45- 60 days after planting while net assimilation rate was more in the early growth stages. Validation of statistical models for Jyothi such as models based on weekly weather variables, fortnightly weather variables, crop stage-wise weather variables and that based on composite weather variables, were carried out in which model which uses composite weather variables was selected as the best one in yield prediction of Jyothi after comparing the estimated yield and observed yield. Crop weather model using statistical methods was also developed for Jyothi and Jaya with the aid of principal component analysis. Two principal components were identified for Jaya and three for Jyothi. The regression analysis was carried out using SPSS software. This formed a better tool in predicting the yield of Jyothi and Jaya. DSSAT CERES- Rice model was also run for Jyothi as well as for Jaya after creating weather file, soil file, crop management file and experimental file for the year 2018.