PG Thesis

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Subject: search.filters.subject.DSSAT

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    Crop weather relationship of rice varieties under different growing environments
    (Department of Agricultural Meteorology, College of Horticulture, Vellanikkara, 2019) Haritharaj, S; Ajithkumar, B
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    Carbon sequestration and crop weather relations in long term fertilizer experiments
    (Academy of Climete Change Education and Research, Vellanikkara, 2018) Sudhamani, P; Thulasi, V
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    Crop weather simulation model in tomato (solanum lycopersicum L.)
    (Department of Agricultural Meteorology, College of Horticulture, Vellanikkara, 2018) Navyasree, S; Ajithkumar, B
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    Modeling rice production in kole lands and its vulnerability to climate change
    (Academy of Climate Change Education and Research Vellanikkara, 2018) Surabhi, S R; Sandeep, S
    Rice is the most important staple food crop for more than 2/3rd of India’s population, and is the primary source of food for more than three billion people globally. Hence rice production plays a significant role in food security under a changing climate. The Kole lands is a multiple use wetland ecosystem covering an area of 13,632 ha spread over Thrissur and Malappuram districts, and form one of the rice granaries of Kerala. It is a part of the unique Vembanad-Kole wetland ecosystem. The objectives of the study were to develop crop weather relationship for the predominant rice varieties and assess possible changes in yield due to climate change and to study the impact of abiotic factors and farming practices on rice production using simulation model. Daily weather data for the period 1998-2016 were collected from the India Meteorological Department, Thiruvananthapuram. Information on area, production and productivity of rice in Kole lands was collected from Agriculture Statistics Report - Department of Economics and Statistics, Kerala. The weather data from General Circulation Models based on RCP 4.5 and 8.5 were used for the analysis and projections were made up to 2050. Weather cock v.1.5 was used for converting the daily weather data into standard week, month and seasonal formats. The rainfall parameters or indices like seasonal and monthly rainfall, rainy days and high rainfall events were calculated. It is also used to compute PET and Thornthwaite water balances. The crop simulation model DSSAT –developed by IBSNAT was used for studying the impact of climate change on these ecosystems. The monthly rainfall of Kole lands indicates that there was an increase in rainfall during the months of June, July and August as per RCP 4.5 and 8.5. According to RCP 4.5 and 8.5 an increasing trend in number of seasonal rainy days was observed during the monsoon seasons. The maximum amount of potential evapotranspiration was observed during the month of May, whereas the minimum in, November December, and January. The months of January, February, March, April, November and December were found to have no surplus. Whereas water deficit is projected to happen during the month of march. The maximum amount of surplus was found to occur in July and the yearly value shows an increase from the current condition. The area under rice production has shown a declining in Kole lands over a period of 2008 – 2017. Results indicates that the productivity of rice in Kole lands during the first cropping season was 2.08 t/ha. By 2030, the second cropping season was projected to have a yield of 3.124 t/ha. By 2050, the third cropping season would surpass the productivity of first two seasons with productivity of 3.424 t/ha.
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    Modeling the rice production under varied agro ecological situations of Palakkad district and its vulnerability to climate change
    (Academy of Climate Change Education and Research Vellanikkara, 2018) Anandu S Hari; Sunil, K M
    The research project entitled "Modeling the rice production under varied Agro-Ecological Situations of Palakkad district and its vulnerability to climate change". Was carried out at RARS Pattambi and the daily rainfall data for the period 1991-2014 was collected from the India Meteorological Department, Thiruvananthapuram. The weather data from General Circulation Models based on RCP 4.5 and 8.5 were used for the analysis and projections were made up to 2050. Weather cock v.1.5 was used for converting the daily weather data into standard week, month and seasonal formats. The rainfall parameters or indices like seasonal and monthly rainfall, rainy days and high rainfall events were calculated. It is also used to compute PET and Thornthwaite water balances. The crop simulation model DSSAT-developed by IBSNAT was used for studying the impact of climate change on these ecosystems. The monthly rainfall of various Agro ecological units of Palakkad district indicate an increased rainfall during the months June, July and August in Projected climate as per RCP 4.5 a weakening in rainfall can be noticed during the months January, February, September and December in projected climate, annually, the number of rainy days indicates a declining trend in projected climate. In a nut shell, the wet months will be watter and dry periods will be drier. The south west monsoon and summer season shows an increasing tendency in the number of rainy days and amount of rainfall in projected climate. Most of the agro-ecological units in Palakkad district showed a decreasing pattern in the length of growing period in projected climate as per RCP 4.5 In projected climate, the maximum amount of potential evapotranspiration can be observed during the months May, July and September whereas the minimum will be in January, November and December. The yearly potential evapotranspiration shows an increasing trend in projected climate as per RCP 4.5. The number of periods where deficit will happen indicate a decreasing trend whereas the annual amount of deficit shows an increasing pattern in projected climate. As per the projections maximum amount of water deficit will happen during the month March in most of the agro ecological units of central Kerala. Annually the amount of water surplus indicates an increasing trend in projected climate based on RCP 4.5. In RCP 4.5, which is the most likely scenario for India, the yield reduction will be 10 per cent by 2030s and 2050s respectively. It can be observed from the study that the impact of climate change on rice production varied widely under different agro ecological situations. The major rice growing tracts of Palakkad district except Palakkad eastern plains (AEU 23) showed decline in productivity.
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    Climate change adaptation through improved water use efficiency in rice (Oryza sativa L.)
    (Academy of Climate Change Education and Research Vellanikkara, 2016) Anjaly C Bose; Santhoshkumar, A V
    The food security of more than half of the world population depends on rice. Studies suggest that global climate change is going to affect the food production through temperature and water stress and this affect the rice production around the globe. The present study tried to elucidate the influence of varying soil moisture status on rice productivity and evaluate the strategies for increased water use efficiency in a climate change adaptation strategy. The study was conducted during May 2016-September 2016 at RARS, Pattambi in variety Jyothi. The treatment combination included the presence or absence of hydrogel along with 4 different levels of irrigation (IW/CPE=2, IW/CPE=1.5, IW/CPE=1 and IW/CPE=0.5). The results showed that the various irrigation levels and hydrogel application had a significant impact on the physiology of rice. Hydrogel application improved the soil moisture availability and increased plant establishment. The maximum plant height was observed for the treatment IW/CPE=2 (105.30 cm) without hydrogel. The hydrogel effect on plant height was significant only up to the booting stage. Hydrogel had its significance on number of tillers only at the vegetative stage of the plant, while, interaction was significant at the vegetative, reproductive and ripening stages. The higher value (19.67) of tiller number was recorded for the treatment IW/CPE=1.5 with hydrogel. LAI was not affected by the application of hydrogel. Only the irrigation treatments had a significant effect on LAI, of which the treatments IW/CPE=2 (2.72) and IW/CPE=1.5 (2.61) recorded the maximum LAI. Higher number of primary branches per panicle was recorded for plants with hydrogel (10.25). The number of panicle per hill was more for the treatment IW/CPE=1.5 without hydrogel (9.20). The number of filled grains produced per panicle is more for plants with hydrogel (86.00). 1000 grain weight observed was higher for the treatment IW/CPE=2 (27.23 g) without hydrogel. Hydrogel did not have any significant effect on the plants physiological parameters like booting, heading, flowering, number of days taken for active tillering and panicle initiation. The more stressed plants took the maximum number of days to booting, heading, flowering and panicle initiation. For the treatment IW/CPE=0.5, there seen no sign of 50 percent flowering and consequently, it did not attained physiological maturity. Hydrogel and irrigation had a significant impact on grain yield. Even though the higher yield (7014.63 kg ha-1) was observed for the irrigation level IW/CPE=2 without hydrogel, the mean average value of grain yield of plants treated with hydrogel is higher than plants treated without hydrogel (4455.03 kg ha-1 and 3951.80 kg ha-1 for with and without hydrogel). It can be concluded that hydrogel had significance only when the irrigation level was low (IW/CPE=1.5 and IW/CPE=1). However, at extreme low water level (IW/CPE=0.5) and high water level (IW/CPE=2), hydrogel failed to exhibit any beneficial role. Under the projected climate scenario using RCP 4.5, it was found for the year 2030 the maximum yield was observed for the treatment IW/CPE=2 (6010 kg ha-1), followed by comparable yield in the treatment IW/CPE=1.5 (5997 kg ha- 1 ). The production was found to be less in the treatment IW/CPE=1 (3504 kg ha-1) and nil to the treatment IW/CPE=0.5. For the year 2050 and 2080, the maximum yield was for the treatment IW/CPE=2.