1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Impact of projected climate change on cropping pattern of different agro ecological units of southern Kerala(Academy of Climate Change Education and Research Vellanikkara, 2017) Sukanya, K S; Sunil, K MClimate change poses an emerging threat to sustainability of social and economic development, livelihoods, and environmental management across the globe. Characterization of the ecosystems using the AEZ concept is a good decision making approach for variety of farming activities performed by the farmers and is a useful tool for the studying the impact of climate change. The objectives of this study are (1) to study rainfall variability and to determine water availability periods of Agro ecological units of southern Kerala under different climate change scenarios. (2) To study the impact of projected climate change on cropping pattern, crop calendar and the possible changes in the water requirements of major cropping systems prevailed in the various Agro ecological Units of southern Kerala. Daily rainfall data for the period 1991-2014 were collected from the India Meteorological Department, Thiruvananthapurm. Weather cock v.1.5 was used for converting the daily weather data into standard week, month and seasonal formats. It is also used to compute PET and Thornthwaite water balances. CROPWAT model was used for the calculations of crop evapotranspiration, crop water requirements and irrigation requirements for the development of irrigation schedules under various management conditions and scheme water supply. The annual rainfall availability in most of the AEUs of Thiruvananthapuram, Kollam and Pathanamthitta districts show a decreasing trend in the projected climate and an increasing trend in Idukki, Kottayam and Alappuzha. The number of annual rainy days generally shows a decreasing trend. The seasonal rainfall of southwest and summer monsoon will show an increase from the current situation where as northeast monsoon and winter will have a decreasing trend. In projected climate of both RCP 4.5 and 8.5 there will be high probability of having reduction in the number of months having the surplus and an increase in the number of deficit. The crop evapotranspiration values of rice based cropping system will show a tendency to increase. In perennial cropping systems of coconut based and rubber the projected crop evapotranspiration will have a reduction from the present situation whereas in coffee based cropping system the ETc will have an increasing trend. The irrigation requirement of all the major cropping systems will increase from the present situation except in the case of rice-fallow-fallow. The length of growing period of the cropping season in the major rice growing areas of different AEUs are getting shorter with slight differences among various agro-ecological units, implying a higher risk of operating under projected climate as per RCP 4.5. The sowing date will be delayed up to three to five weeks. It can be also observed that the crops will have to suffer water stress during the grain filling stage and will be under heavy rains at time of harvest in almost all the considered cases.Item Quantify the temporal carbon, water and energy fluxes in selected land use systems in Himalayas(Academy of Climate Change Education and Research,Vellanikkara, 2019) Arya, M S; Nameer, P OAn investigation entitled “Quantify the temporal carbon, water and energy fluxes in selected land use system in Himalayas” was conducted at Forest Research Institute (FRI), Dehradun, during 2018 December to May 2019. The experiment was conducted in two seasons winter (December-February) and summer (March-May) with four land use i.e.; mixed forest, pine forest, grassland and bamboo forest. Soil physical properties are also considered at the depth of 015cm and at 15-30cm. The study aimed to give an insight of carbon, water and energy flux variations along micrometeorological observations. The results revealed that during summer season (air temperature increased) all the respective observed fluxes significantly rose, among selected land use. Grassland showed high flux release from the system to the atmosphere. While mixed forest, soil experienced gradual rise in flux exchange, but pine forest system stores greenhouse gases like carbon dioxide in a long time period in a safe manner. Apart from flux, soil temperature and soil moisture were also examined and obtained data showed a decrease in moisture and increase in soil temperature with air temperature rise except leaf shedding months. As the study show that different land use had evident impact on variability in climatic conditions and hence more than considering the green covers, specific land use flux exchange monitoring is required for all terrestrial land use.Item Soil water balance studies in subsurface drip irrigation for amaranthus(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Neetha Shaju; Priya G NairSubsurface drip irrigation (SDI) is advanced drip irrigation where the tubing and emitters are buried beneath the soil surface. Field experiment was done at the instructional farm, KCAET, Tavanur. Experiment was aimed to optimize the depth of installation of laterals and spacing between laterals under subsurface drip system. This study also computed deep percolation from different layers with different lateral depths. Soil moisture was taken from different depths and horizontal distance and soil moisture contour maps were plotted. Results showed that moisture content increased with depth from the surface due to less evaporation loss. Also, amount of moisture was found to be decreased with time. Moisture content at the surface layer for 10 cm lateral was 14.5 per cent whereas the same for 20 cm lateral was 11.6 per cent due to surfacing. Moisture distribution pattern was uniform for lateral with 15 cm depth. Maximum values of yield were observed for the treatment T4, and then T1 (which have 15 cm and 10 cm lateral depth respectively). Highest water use efficiency was for treatment T4 with a value of 37.96 kg/ha-mm followed by treatment T1 with 34.6 kg/ha-mm. In statistical analysis, it was observed that, there were significant variations between treatments. Number of leaves was influenced by both spacing between laterals and depth of laterals. Stem girth was varied significantly by spacing between laterals. Both spacing between laterals and lateral depth had remarkable effect on crop height. Deep percolation was relatively less from the surface layers than from the deeper layers in higher lateral depths (i.e., 20 cm lateral depth). From this study, it is evident that treatment T4 (lateral spacing = 95 cm, lateral depth= 15 cm) has showed maximum response while considering moisture distribution, crop yield, biometric properties and deep percolation.Item Fertigation and mulching in oriental pickling melon (Cucumis melo var. conomon (L.) Makino) under high density planting(Department of Agronomy,Vellanikkara, 2016) Ashly, P; Joseph, P AItem Effect of hydrogel and mulching on maize (Zea mays L.) in sandy soil(Department of Agronomy, College of Agriculture, Padannakkad, 2018) Rajap Shiva Kumar; Bridgit, T KAn investigation entitled “Effect of hydrogel and mulching on maize (Zea mays L.) in sandy soil” was carried out at College of Agriculture, Padannakkad during 2016- 2018 to study the effect of hydrogel (super absorbent polymer) and mulching on soil moisture status, growth and yield of maize in sandy soil. The experiment was laid out in factorial randomized block design with three replications. The treatment combinations included three levels of hydrogel viz. H1 – 1.25 kg ha-1, H2 – 2.5 kg ha-1, H3 – 3.75 kg ha-1 and three types of mulch viz. M1 – rice straw (5 t ha-1), M2 – rice husk (5 t ha-1), M3 – coirpith compost (2.5 t ha-1) and one control (KAU Package of Practices recommendations). Observations were recorded on growth and growth attributes, yield and yield attributes, plant analysis, soil analysis and economics. Hydrogel @ 2.5 kg ha-1 and rice straw mulch @ 5 t ha-1 recorded maximum plant height, dry matter production and root volume of maize whereas maximum leaf area and LAI were observed in hydrogel @ 3.75 kg ha-1 and rice straw mulch @ 5 t ha-1. The yield and yield parameters such as cob, grain and stover yield were found to be higher in treatments receiving hydrogel @ 2.5 kg ha-1 and rice straw mulch @ 5 t ha-1 than other levels of hydrogel and types of mulch. The response of hydrogel @ 2.5 kg ha-1 and rice straw mulch @ 5 t ha-1 was significantly superior over other treatments with respect to total N and P uptake. While total K uptake recorded was maximum in the case of hydrogel @ 3.75 kg ha-1 and rice straw mulch @ 5 t ha-1. The major beneficial effect of hydrogel was in enhancing and maintaining soil moisture status of coarse textured sandy soil at 15 and 30 cm depth. The treatment receiving hydrogel @ 3.75 kg ha-1 and rice straw mulch @ 5 t ha-1 recorded maximum soil moisture retention. The maximum porosity was recorded in the case of hydrogel @ 3.75 kg ha-1 and coirpith compost mulch @ 2.5 t ha-1. The residual nutrient status with respect to available N and K2O recorded maximum values in hydrogel @ 1.25 kg ha-1 and rice husk mulch @ 5 t ha-1 and available P2O5 was maximum with hydrogel @ 3.75 kg ha-1 and rice husk mulch @ 5 t ha-1. Considering the economics of maize crop production, the gross and net income obtained were maximum in hydrogel @ 2.5 kg ha-1 and rice straw mulch @ 5 t ha-1. However, BCR was found to be maximum in treatment with hydrogel @ 2.5 kg ha-1 and rice husk mulch @ 5 t ha-1. The maize growth and yield were significantly improved by the application of hydrogel and different mulches. Hydrogel @ 2.5 kg ha-1 in combination with rice straw mulch @ 5 t ha-1 was most efficient and economical compared to other combinations and can be recommended for maize cultivation in sandy soils of KeralaItem Climate variability impact on water resources in the command area of a river diversion scheme(Academy of Climate Change Education and Research, Vellanikkara, 2017) Abhijith, V; KAU; Mary Regina, FClimate change is the major cause that affects water availability mainly due to variability in rainfall and temperature. The rising population and increasing food demands are imposing a further pressure on available water resources. Hence the efficient management of available water resource is of great concern. Irrigation is the largest sector that accounts for water use. In this situation a study was conducted in the command area of Left Bank Canal of Chalakudy River Diversion Scheme to assess the impact of climate variability on the water availability for the cropping systems and domestic demand during the irrigation period from December to May. The variability and trend in the rainfall was studied for the basin for a period from 1987 to 2016 and it is seen that the annual rainfall shows a declining trend. An investigation was done for finding out the cropping pattern of the canal commands. The crop water demand worked out using CROPWAT was used to estimate irrigation water demand. The domestic water demand calculated for the basin along with the irrigation water requirement constituted the net water demand. The total weekly water requirement was computed for all the branch canals for the irrigation period. The groundwater level analysis was done for wells along branch canals. Water recharge was observed in almost all the observation wells during supply periods. But no recharge was observed in wells in tail reaches during certain supply periods due to insufficient supply of water to tail ends. The weekly water supply for the branch canals were compared with the water demand. Most branches show a water deficit while a few exhibits water excess. Water deficit was observed mostly in longer and farther branches. The existing supply system was noted to be inefficient and works without considering proper branch wise water demand. The discharge from the main shutter was also obtained and was found to be almost about five times of the demand. Seepage losses, illegal withdrawal of canal water, and improper management are observed to be the reasons behind the insufficient water supply. Proper management of canals and supply based on demand has to be followed for efficient water management. A computer based model was developed for the calculation of weekly water demand based on crop and weather data. A comparison of supply with the demand can also be done in the model which indicates the efficiency of supply system on a weekly basis. Proper planning can be done for efficient water management through the canal system, under the given conditions using the model.Item Swat model evaluation using generated data and assessing the impact of land use changes(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2018) Nethi Naga Hari Sairam; Anu VarugheseLand and water are the primary natural resources which are useful for all the living beings on earth surface. Degradation of the land surface and lack of water availability are the two major important problems mankind is facing in this century. In order to overcome these problems, there is a need of effective management of these resources. Watershed models are the tools which are not only useful for the effective management of these natural resources, but also useful for the proper understanding of the hydrological behavior of the watershed. These models play a vital role in simulating the hydrology of the watershed. Among the different categories of the model, a physically based, semi distributed hydrologic model SWAT was used for the assessment of the calibration and validation of the hydrologic model SWAT adapted to the study area. The data scarcity is one of the major problems in the ungauged watersheds. In order to overcome this problem, CFSR (Climate Forecast System Reanalysis) data which is a global, high resolutions, coupled atmoshphere ocean land surface sea ice system is available as an alternative option for solving the data deficiency in the watershed. The land use change also plays a vital role in altering the hydrologic system and has a large impact on the stream flow. This is mainly due to the rapid socio economic development. So, based on the above mentioned problems, SWAT output comparison using CFSR & observed meteorological data as inputs was take up. The impact of land use change on the hydrology of watershed was also studied. The platform used for the study was ArcGIS 10.3 with the Arc SWAT interface. The SWAT model set up was done for the Kunthipuzha river basin and the calibration and validation of the model was also done to make the model suitable for use in the area. This model was later used to understand the hydrologic behaviour of the watershed. The model was simulated for the period 1991 to 2013 for calibration and validation of the model was done using the data for the period 2014 to 2016. Before the model calibration and validation, sensitive parameters were evaluated using SWAT CUP (Calibration and Uncertainty Program). CN2 (Initial SCS runoff curve number for moisture condition II) and ALPHS_BF (Base flow alpha factor) were found to be the most sensitive parameters for the study area. The NSE and R2 before and after calibration were 0.81 & 0.83 and 0.82 & 0.85 respectively. The NSE and R2 for the validation were 0.70 & 0.87 respectively. Based on the statistical measures and the criteria used, the model performance is "very good" in the calibration period and "Good" in validation period. To analyse the possibility of using CFSR data instead on observed meteorological data, the developed model was run with observed meteorological data and predicted meteorological data (CFSR)was done separately without changing any other inputs for the period 1991 to 2013. The NSE, R2 and RMSE for the observed meteorological data were 0.82, 0.85 and 29.25 respectively where ad for the predicted meteorological data (CFSR) the values were 0.70, 0.72 and 37.18 respectively. Based on the statistical measures, the performance of the observed meteorological data is better than the predicted meteorological data. From the graphical analysis, it was clear that the values of predicted meteorological data were highly correlated with the observed meteorological data except at peaks. Hence, CFSR data can be used as a reliable data source in data scarce areas. The land use change impact play a major role in alternating the stream flow because of the rapid socio-economic development. The land use map for the year 2000 and 2017 were prepared. While comparing the land use for the year 200 and 2017 , it is found that the urban areas drastically increased from 3.01 to 20.01 % because of the rapid socio economic development. The forest land reduced from 22.24 to 21.31%. The percentage area under paddy decreased from 17.57 to 6.12 %. The model was simulated for the period from 1989 to 2016 with the two years of warm up period. Then the comparison of simulated discharge for the year 2000 and 2016 were evaluated. The results showed that there is no significant change in stream flow when the land use alone is changed keeping all other factors same.Item Land use pattern and regional water balance in relation to climate change - a case study of Kanthallor panchayath, Idukki, Kerala(Academy of Climate Change Education and Research Vellanikkara, 2018) Vishnumaya, A P; Jalaja S MenonItem Comparative evalualtion of evapotranspiration parameters in a naturally ventilated polyhouse and open field(Department of Irrigation and Drainge Engineering, Kelappapji College of Agricultural Engineering and Technology, Tavanur, 2017) Madhavi Tulluru; Rema, K PStudies on the water requirement of horticultural crops in polyhouses are scarce and despite the water scarcity, irrigation is mainly scheduled according to farmer’s experience. Canopy development and management of some polyhouse horticultural crops is quite different from that outdoors. Differences in plant spacing, crop height and aerodynamic properties may affect the crop coefficient values. Moreover, the proportion of diffuse radiation in polyhouse is different from that outdoors. Thus it is questionable whether the standard crop coefficient values, determined experimentally outside polyhouse can be used directly to determine the evapotranspiration of the greenhouse crops. Complete data on meteorological parameters inside poly houses is very rarely obtained and it causes lot of limitations in applying indirect estimation methods of ET0 based on climatological data. Field experiment on the comparative evaluation of evapotranspiration parameters in a naturally ventilated polyhouse and open field was conducted in a naturally ventilated polyhouse and open field in the research plot of the Department of Irrigation and Drainage Engineering, in KCAET campus, Tavanur. In the study, Non-Weighing Mini-Lysimeters were used to determine evapotranspiration parameters and to develop crop-coefficient curves for Okra. Comparison with indirect methods was also done in order to assess the dependability of climatic data for evapotranspiration estimates. The study compares the data for open field and poly house conditions in order to quantify the effect of micro climatic variations. ETo estimated using climatological methods viz reduced pan, FAO -56 Penman-Monteith, FAO Blaney- Criddle and Thornthwaite were compared with measured lysimetric data using simple error analysis and linear regression. Out of all methods FAO-56 Penman-Monteith provides quite good agreement with evapotranspiration obtained by lysimetric data with a high correlation coefficient of 0.88 and 0.87 for polyhouse and open field conditions respectively. Studies on crop morphological parameters indicated that plant growth and yield parameters were not significantly different for polyhouse and open field conditions. Seasonal average ETo for polyhouse and open field were 4.74 and 5.02 mm/day. Seasonal average ETc values of Okra for polyhouse and open field conditions were 3.90 and 4.31mm/day. The calculated values of Kc for the initial, mid and late season stages were 0.58, 0.94 and 0.67 in polyhouse. Open field values were 0.61, 0.98 and 0.72 for different stages respectively. It was observed that polyhouse Kc values were lower than the open field. The variations in micro climate inside poly houses with reduced solar radiation and wind velocity combined with higher humidity and temperature may have contributed to lesser ET. The results implied that water requirement is lower inside the polyhouse compared to open field conditions. The results of this study can be used as a guideline in the computation of water requirement of poly house crops instead of depending on open field accepted values for Tavanur region. If the poly house irrigation is scheduled in such a way as to apply the right quantity of water enough to meet the evapotranspiration requirements of crops, considerable water saving can be achieved. The quality of produce is high, duration of crop season is longer and year round cultivation is possible inside poly houses which implies significant saving in water without compromising yield and product quality.Item Assessment of evapotranspiration models for the humid tropical region of Tavanur(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2017) Pravalika, Y R; Asha JosephWorld is facing an acute water crisis due to the increase of world population, droughts, land degradation, and food demand. This increases the concern over conservation of water. One of the most important factors related to water management is crop evapotranspiration. In the present research work, the reference crop evapotranspiration (ETo) is estimated by using ten empirical models which are widely used in Indian conditions namely, Thornthwaite (1948), Hargreaves et al., (1985), Turc (1961), Christiansen (1968) Pan Evaporation, FAO-24 Blaney-Criddle (1977), FAO-24 Modified Penman (1977), FAO-24 Open Pan (1977), Preistly-Taylor, Makkinik and FAO-56 Penman-Monteith (1991). The accuracy of these reference evapotranspiration models were evaluated by comparing it with FAO-56 Penman-Monteith using six years monthly average meteorological data for the period January, 2011-December, 2016. Then the models were validated with lysimetric data. The weekly water balance studies were conducted in lysimeter to find the actual reference evapotranspiration. The model values were estimated using weekly meteorological data for the period January-May 2017 during which the lysimeter study was conducted. Then best fit relations were developed between the estimated values (EToEST) and observed values (EToLYM) for the humid tropical region. Among the different empirical models, Turc model showed the highest ETo value (14.92 mm/day) while the Priestly-Taylor showed the lowest (0.62 mm/day). Thornthwaite, Blaney-Criddle and Modified Penman model gave closer values to each other 7.32, 8.9 and 7.09 mm/day respectively. While Christiansen, Penman-Monteith, Open Pan and Makkinik models gave values like 3.08, 3.23, 3.24 and 2.22 mm/day respectively which were slightly lower compared to the values obtained from the Hargreaves model (4.7 mm/day). The statistical comparison was made by considering FAO-56 PMM as the standard model using six year average monthly meteorological data. The Modified Penman model gave the best performance with R2 of 0.96 with RMSE 3.95 and RelRMSE 1.22 followed by Hargreaves model. The Open Pan method ranked the third one. The models, Christiansen, Priestly-Taylor and Makkinik were underestimated while Thornthwaite, Turc and Blaney-Criddle models overestimated. For validation of the models, weekly ETo estimated from models were compared with ETo observed from lysimeter for the period January-May, 2017. The Hargreaves model showed the best performance with R2 0.83 and RMSE 0.82. The Turc model was highly over estimated while Blaney-Criddle and Modified Penman models were only slightly overestimated. The Penman- Monteith and Makkinik models were slightly underestimated while Priestly- Taylor highly underestimated with R2 0.56 and the RMSE 4.29. Hence it is concluded that Hargreaves (HAM), Open Pan (OPM) and Christiansen (CHM) models were found to be in close agreement with lysimetric data and hence these models were suggested for use in this humid tropical region. Therefore relationships were developed between these empirical model output and the lysimetric data (LYM). The relationships developed were as follows: ETo LYM = 0.79HAM + 0.45, EToLYM = 0.79CHM + 1.60 and EToLYM = 0.63OPM + 2.04. Finally the results of this research can be recommended for humid tropical region for irrigation scheduling, selection of cropping pattern, optimum allocation of water resources and efficient use of water.