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ThesisItem Open Access Optimization of agronomic resources for maximizing grain and mill yield of rice(Department of Agricultural Engineering, Indian Institute of Technology, Kharagpur, 1976) Kannan, Mukundan; KAU; Pande, H KAn investigation was planned during the main growing season, i.e., ‘aman’ (June to November ) to find out the optimum levels of the major inputs for rice cultivation such as nitrogen, phosphate, and water, associated with the management practices like optimum time of harvest, in order to maximize production and to obtain quality paddy which, when processed, should give a high quality rice and thereby high economic return. Keeping the above points in view, four field experiments were conducted during two consecutive ‘aman’ seasons of 1972 and 1973 in a cultivators’ field at abhoy Ashram, Balaramapur which is located about 3 km south – east of the Institute. The farm soil was silty – clay – loam, having a pH of 8.1. The experiments were conducted with the high – yielding rice variety IR 22 to study its performance under three levels each of nitrogen, phosphate and submergence and laid out in 3 x 3 x 3 confounded design. Nine additional plots to accommodate ‘o’ levels of nitrogen and phosphate were included for fitting production functions. In the first year of experimentation, the nitrogen and phosphate levels were 60, 120 and 180 kg/ha and 30, 60 and 90 kg/ha respectively. In the second year, the levels were 60, 90 and 120 kg N/ha and 30, 45 and 60 kg P2O5/ha. The modification in the levels of nitrogen and phosphate, in the second year, were made on the basis of the findings of the first year of experimentation. In both the years, the levels of submergence were kept constant, i.e., 0 – 5 cm, 5 + 2 cm, and 10 + 2 cm. For finding out the optimum grain moisture at harvest, suitable for higher milling yield, the crop was harvested at 25.5 – 22.5, 22.5 – 19.5 – 16.5 and 16.5 – 13.5 per cent grain moisture. The optimum levels of each input for maximizing grain yield and head yield were found out by fitting production functions. To identify a suitable variety under a specific management of production and processing, four high yielding rice varieties – Sona, Jayanthi, Pankaj and IR 22 were grown in ‘aman’ season of 1972 and 1973 with similar levels of nitrogen and phosphate as mentioned in Experiments 1 and 2; an additional treatment, with nitrogen and phosphate at ‘o’ level was also included. These experiments were laid out in 4 x 4 x 4 confounded design. The crop was grown under continuous submergence of 5 +2 cm and was harvested at grain moisture content ranging between 19.5 and 16.5 per cent. Treatment wise experimental details and the salient findings are given in the following pages. Positive response with reference to grain yield, total mill yield and head yield of variety IR 22 was noted up to 90 kg N/ha and 45 kg P2O5/ha. Further increase in nitrogen and phosphate levels to 120 kg/ha and 60 kg/ha respectively did not and its percentage was minimized by harvesting the crop above 19.5 per cent grain moisture or between 26 and 30 days after flowering. However, by increasing the level of nitrogen from 90 to 120 kg/ha and 120 to 180 kg/ha, the head yield and its recovery percent was less affected even when the crop was harvested with some delay, i.e., between 19.5 and 16.5 per cent grain moisture or between 35 and 37 days after flowering. The influence of phosphate on grain yield and milling quality, particularly head yield recovery percentage, was more pronounced when considered in combination with grain moisture at harvest. A suitable water management practice, of growing the crop with shallow submergence of 5 + 2 cm was found beneficial in increasing the yield as well as the milling and head yields. The influence of submergence on the head yield recovery percentage was, however, not to the same extent as that of nitrogen and grain moisture at harvest. On fitting the function, for variety IR 22, it could be ascertained that maximum grain yield to the extent of 5112 kg/ha can be attained with the optimum levels of 119 kg N/ha, 59 kg P2O5/ha, 149 cm of water and 22.4 per cent grain moisture at harvest which corresponded to harvesting the crop about 30 days after flowering. On the other hand, maximum head yield to the extent of 3562 kg/ha can be attained with the optimum levels of 124 kg N/ha, 51 kg P2O5/ha, 159 cm of water and around 26 per cent grain moisture at harvest which corresponded to harvesting the crop about 26 days after flowering. The grain yield and consequently, the gross and net returns were maximum under the same levels of nitrogen, phosphate, submergence and grain moisture at harvest. However, from an assessment of rough rice and polished rice along with broken, bran and husk, it was ascertained that the increase in net return to the extent of 984 k/ha was possible only by processing the rough rice. The positive response in grain yield of all the varieties was found only up to 90 kg N/ha and 45 kg P2O5/ha. In varietal comparison, grain yield, mill yield, head yield and net return were found to be maximum in case of the variety Pankaj, amounting to 5192 kg/ha, 3768 kg/ha, 3027 kg/ha and 1716 Rs/ha respectively. The variety Pankaj was followed by IR 22, Sona and Jayanthi in order. However, in milling quality, particularly head yield recovery percent, IR 22 was found superior to all the other varieties. Further, the variety IR 22, with along and slender grains, proved superior in quality to Pankaj, with long and bold grain. The former, eventually, has higher market value that brought higher return. These characteristics in IR 22 narrowed the difference in profit, when compared to Pankaj, though the latter has significantly higher grain yield the additional net return over milled rice was estimated at 877 Rs/ha in case of IR 22 and 833 Rs/ha in case of Pankaj. The agro – climatic conditions of this region of West Bengal, where rice is the only crop during ‘aman’, provide better prospects for cultivation of variety IR 22 as well as Pankaj. In quality criteria as well as growing period, IR 22 may prove superior to Pankaj. Their cultivation for higher yield and quality rice is possible only through suitable levels of fertility and water inputs as well as management input which includes the timeliness of operations, particularly harvesting, because it has a greater impact on the final outturn of the produce as quality rice.ThesisItem Open Access Impact of climate change and watershed development on river basin hydrology using SWAT – a case study(Department of irrigation and drainage engineering, Kelappaji college of agricultural engineering and technology, Thavanur, 2016) Anu Varughese; KAU; Hajilal, M SClimate change is considered as a global phenomenon, but investigation at the regional level is essential to understand the changes induced, and to suggest suitable adaptation strategies. This study is mainly concerned with the analysis of possible changes in the hydrology of Bharathapuzha river basin in the state of Kerala, India. Initially the trend in historic climate data was analysed to get an idea about the changes happening in the area. The trend analysis of gridded data using Mann-Kendall and t-test showed that the mean, maximum and minimum temperatures during 1951-2013 showed a significant increasing trend and the increase in mean, maximum and minimum temperatures during the period was at the rate of .07°C/decade, 0.14°C/decade and 0.04°C/decade respectively. Trend analysis of gridded rainfall data for the period 1971-2005 showed statistically significant decreasing trend, at the rate of 15 mm/year. Trend analysis of seasonal rainfall indicated that there was no significant trend in seasonal rainfall except during the south-west monsoon period when there was an increasing trend. To find out the best suitable climate model for the region, the downscaled reanalysis data on precipitation and temperature from five regional climate models (RCM’s) derived from different Global Climate Models (GCM’s) were compared with observed data of area on the basis of the four statistical parameters (standard deviation, correlation coefficient, coefficient of variation and centred root mean square difference). The GFDL-CM3 RCM gave better comparison with the observed data and hence was used for further data analysis. Bias in precipitation was corrected using power transformation which corrects the mean and coefficient of variation (CV) of the observations. Since temperature is approximately normally distributed, it was corrected by fitting it to the mean and standard deviation of the observations. The model data for two emission scenarios RCP4.5 and RCP8.5 and two scenario periods 2041-70 and 2071-99 were selected for the study. Comparison of the post-processed climate data to observed climate data was carried out. Based on the results obtained, the annual maximum and minimum temperatures is expected to increase in future. It is also predicted that there will be a decrease of 4 to 7 per cent in average annual rainfall during 2041-70 compared to the present day average values, whereas the decrease will be up to 10 to 15 per cent during 2071-99. To evaluate the surface runoff generation and soil erosion rates from the area, the Soil and Water Assessment Tool (SWAT) model was used. The model was calibrated and validated on a monthly basis using the observed data and it could simulate surface runoff and soil erosion to a good level of accuracy. The model evaluation statistics used for the calibration and validation periods were Nash-Sutcliffe Efficiency (NSE), Coefficient of determination (R2) and PBIAS. The study demonstrated that the SWAT model can be used to predict the monthly stream flow and sediment loss from the basin. So the calibrated and validated model was then used for studying the impact of changes in climate and watershed interventions on the hydrology of the river basin. The model predicts 15 to 20 per cent decrease in stream flow by the end of the century if the worst situation of climate change continues (RCP8.5). While analysing the water balance components, it is seen that ET ranges from 15 to 22 per cent of the annual rainfall in the current scenario, while it may increase to 29 to 32 per cent in the RCP4.5 scenario and 32 to 35 per cent in RCP8.5 scenario. Lateral flow component is the lowest, comprising only 8 to 10 per cent of the total rainfall and there is no much variation for this component within the scenarios. Monthly streamflow predicted for the two periods 2041-2070 and 2071-2099 when compared with the current scenario values shows that irrespective of the scenarios, the streamflow is found to be less than that of the current scenario in almost all months. During 2046-2070, the sediment loss in RCP4.5 scenario is predicted to be much less than the RCP8.5 scenario, whereas to the end of the century, the sediment loss in RCP8.5 scenario is greater than RCP4.5 scenario in almost all years, and the annual sediment loss goes up to 7 to 9 t/ha, from the present condition of 2.5 to 4 t/ha.The impact of watershed interventions on the river hydrology was studied based on 0.05, 0.1 and 0.2 per cent increase in Water Retention Structures (WRS) in the area. The monthly stream flow simulated for the period 2007 to 2011 after adding WRS showed that even though the annual river flow decreased, the flow during the summer months (base flow) increased after adding the WRS and the percent increase in flow was highest during the months of January to April when the river has a very lean flow. Rather than utilizing the stored water in the upper reaches for irrigation and domestic purpose, the increase in summer flow will be helpful for maintaining a better environmental flow regime. Though the decrease in annual streamflow due to the WRS is small (1 to 6 per cent), the redistribution of peak flow to the summer months is significant. The annual streamflow in the current scenario is found to be decreasing with increasing capacity of the water storage structures. Streamflow prediction for the period 2041-2069 under the two scenarios RCP4.5 and RCP8.5 with WRS showed that the monthly stream flow could be increased by 5 to10 per cent due to the addition of the WRS during December to March. The water stored on account of increased WRS can be utilized for irrigation and domestic purpose in the upper reaches and at the same time the increase in summer flow will be helpful for maintaining a better environmental flow regime.ThesisItem Open Access Impact of climate change and watershed development on river basin hydrology using SWAT – a case study(Kelappaji College of Agricultural Engineering and Technology, Thavanur, 2016) Anu, Varughese; KAU; Hajilal, M SClimate change is considered as a global phenomenon, but investigation at the regional level is essential to understand the changes induced, and to suggest suitable adaptation strategies. This study is mainly concerned with the analysis of possible changes in the hydrology of Bharathapuzha river basin in the state of Kerala, India. Initially the trend in historic climate data was analysed to get an idea about the changes happening in the area. The trend analysis of gridded data using Mann-Kendall and t-test showed that the mean, maximum and minimum temperatures during 1951-2013 showed a significant increasing trend and the increase in mean, maximum and minimum temperatures during the period was at the rate of .07°C/decade, 0.14°C/decade and 0.04°C/decade respectively. Trend analysis of gridded rainfall data for the period 1971-2005 showed statistically significant decreasing trend, at the rate of 15 mm/year. Trend analysis of seasonal rainfall indicated that there was no significant trend in seasonal rainfall except during the south-west monsoon period when there was an increasing trend. To find out the best suitable climate model for the region, the downscaled reanalysis data on precipitation and temperature from five regional climate models (RCM’s) derived from different Global Climate Models (GCM’s) were compared with observed data of area on the basis of the four statistical parameters (standard deviation, correlation coefficient, coefficient of variation and centred root mean square difference). The GFDL-CM3 RCM gave better comparison with the observed data and hence was used for further data analysis. Bias in precipitation was corrected using power transformation which corrects the mean and coefficient of variation (CV) of the observations. Since temperature is approximately normally distributed, it was corrected by fitting it to the mean and standard deviation of the observations. The model data for two emission scenarios RCP4.5 and RCP8.5 and two scenario periods 2041-70 and 2071-99 were selected for the study. Comparison of the post-processed climate data to observed climate data was carried out. Based on the results obtained, the annual maximum and minimum temperatures is expected to increase in future. It is also predicted that there will be a decrease of 4 to 7 per cent in average annual rainfall during 2041-70 compared to the present day average values, whereas the decrease will be up to 10 to 15 per cent during 2071-99. To evaluate the surface runoff generation and soil erosion rates from the area, the Soil and Water Assessment Tool (SWAT) model was used. The model was calibrated and validated on a monthly basis using the observed data and it could simulate surface runoff and soil erosion to a good level of accuracy. The model evaluation statistics used for the calibration and validation periods were Nash-Sutcliffe Efficiency (NSE), Coefficient of determination (R2) and PBIAS. The study demonstrated that the SWAT model can be used to predict the monthly stream flow and sediment loss from the basin. So the calibrated and validated model was then used for studying the impact of changes in climate and watershed interventions on the hydrology of the river basin. The model predicts 15 to 20 per cent decrease in stream flow by the end of the century if the worst situation of climate change continues (RCP8.5). While analysing the water balance components, it is seen that ET ranges from 15 to 22 per cent of the annual rainfall in the current scenario, while it may increase to 29 to 32 per cent in the RCP4.5 scenario and 32 to 35 per cent in RCP8.5 scenario. Lateral flow component is the lowest, comprising only 8 to 10 per cent of the total rainfall and there is no much variation for this component within the scenarios. Monthly streamflow predicted for the two periods 2041-2070 and 2071-2099 when compared with the current scenario values shows that irrespective of the scenarios, the streamflow is found to be less than that of the current scenario in almost all months. During 2046-2070, the sediment loss in RCP4.5 scenario is predicted to be much less than the RCP8.5 scenario, whereas to the end of the century, the sediment loss in RCP8.5 scenario is greater than RCP4.5 scenario in almost all years, and the annual sediment loss goes up to 7 to 9 t/ha, from the present condition of 2.5 to 4 t/ha.The impact of watershed interventions on the river hydrology was studied based on 0.05, 0.1 and 0.2 per cent increase in Water Retention Structures (WRS) in the area. The monthly stream flow simulated for the period 2007 to 2011 after adding WRS showed that even though the annual river flow decreased, the flow during the summer months (base flow) increased after adding the WRS and the percent increase in flow was highest during the months of January to April when the river has a very lean flow. Rather than utilizing the stored water in the upper reaches for irrigation and domestic purpose, the increase in summer flow will be helpful for maintaining a better environmental flow regime. Though the decrease in annual streamflow due to the WRS is small (1 to 6 per cent), the redistribution of peak flow to the summer months is significant. The annual streamflow in the current scenario is found to be decreasing with increasing capacity of the water storage structures. Streamflow prediction for the period 2041-2069 under the two scenarios RCP4.5 and RCP8.5 with WRS showed that the monthly stream flow could be increased by 5 to10 per cent due to the addition of the WRS during December to March. The water stored on account of increased WRS can be utilized for irrigation and domestic purpose in the upper reaches and at the same time the increase in summer flow will be helpful for maintaining a better environmental flow regime.
