http://localhost:8080/xmlui/handle/123456789/30 2026-04-23T08:16:16Z http://localhost:8080/xmlui/handle/123456789/2036 Climate change impact on irrigation water requirement and crop water productivity of rice Midhula B N; Asha Joseph, (Guide) The study evaluated the impact of climate change on the irrigation water requirement (IWR) and crop water productivity (CWP) of rice in Pattambi, Kerala, using observed climate data from 1991-2022 and projected data for 2025-2095. Climate projections were based on four Global Climate Models (GCMs), MPI-ESM 1-2-HR, ACCESS-ESM 1-5, MPI-ESM 1-2-LR, and INM-CM-5-0 under SSP2 4.5 and SSP5 8.5 scenarios. GCM data was bias-corrected using linear scaling for temperature and power transformation for precipitation. The AquaCrop model, calibrated and validated with RMSE (0.3527-0.3728) and NSE (0.97-0.99), simulated rice yields and CWP, while CROPWAT 8.0 estimated ETo, ETc, and IWR for the baseline and future periods (2025-2049 (2035s), 2050- 2074 (2055s) and 2075- 2095 (2085s)). The climate model INM-CM 5-0 exhibited strong agreement between observed and model-derived data with RMSE (1.5-4.80) and R² (0.5-0.85) in acceptable range. Future projections for the period 2025-2095 indicated that maximum temperatures could rise by +0.6, +0.84, and +0.89°C, minimum temperatures by +0.57, +0.85, and +1.2°C, and precipitation by +96.19, +122, and +214.23 cm during 2035s, 2055s and 2085s respectively under the SSP2 4.5. Under SSP5 8.5, the maximum temperature could rise by +0.66, +1.33, and +1.97°C, minimum temperatures by +0.67, +1.48, and +2.46°C, and precipitation by +159.3, +699.9, and +415.57 cm for the same time horizons. The AquaCrop model was calibrated and validated with RMSE (0.3527-0.3728) and NSE (0.99- 0.97) in the acceptable range for simulating rice yield. Future projections of IWR indicated a remarkable rise in water demand both in Virippu (1st crop) and Mundakan (2nd crop) seasons. During Virippu, IWR is expected to increase by up to +42.63% and +37.97% under SSP2 4.5 and SSP5 8.5, respectively, while the same for Mundakan was found to be +4.20% and +11.65% respectively. This reflected higher water requirements for rice production under future climate change scenarios. Future yield projections showed a reduction in yield both in Mundakan (-51.72% and -42.12%) and Virippu season (-77.38% and -81.97%) under SSP2 4.5 and SSP5 8.5, respectively. However, the Virippu season showed a more prominent reduction in yield than Mundakan. This significantly impacted CWP during Virippu, which showed a sharp reduction of -87.92% and -90.82%, and Mundakan showed a reduction of -66.36% and -46.36% under SSP2 4.5 and SSP5 8.5, respectively. Adopting early transplanting dates, particularly on April 21st, will help to increase yields (+26.2%) and reduce irrigation water requirements (-1.97%), while late transplanting should be avoided due to significant yield reduction in Virippu. But during the Mundakan season, transplanting dates on Oct 12th (in 2035s), Nov 11th (in 2055s), and Nov 21st (in 2085s) were found optimal due to increased yield (+2 - 9.8%). Adopting drip irrigation reduced water use by 20% and improved rice yields by +2.5%. Hence, it is concluded that, rising temperatures and rainfall under future climate scenarios are projected to increase IWR, reduce rice yields, and significantly lower CWP. Hence, adaptation measures are recommended to combat the effect of climate change and enhances CWP. 2025-01-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/2034 Impact of soil and water conservation measures on LULC and groundwater in Olanthichira watershed, Malappuram Revathi, N; Sajeena, S (Guide) 2025-01-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/1985 Refinement and performace evaluation of media bed aquaponic system Arjun Prakash, K V; Suseela, P (Giude) In Kerala, the production of fish and vegetables is much less than that of the daily requirement. In this study, an attempt was made to design and develop an aquaponics system to achieve an efficient, less energy-consuming, problem-free operational system working in a sustainable manner at the Hi-tech Research and Training Unit (HTR&TU), Instructional Farm (IF), KAU, Vellanikkara. The study was also made for selection of suitable media (20 mm gravel/ 8-20 mm broken tiles/ 8-15 mm hydroton/ 8-10 mm gravel), performance evaluation of the two aquaponics systems (S1- Aquaponic system fitted with a conventional siphon system and S2- Aquaponic system fitted with feeder cum operation regulation system) with fruiting plant (Tomato) and leafy vegetable (Lettuce) and developing and evaluating a system for automatic recording of temperature and dissolved oxygen level of water in the fish pond. At all stages, the growth and yield of tomato, lettuce and fish in the S2 system were comparatively higher than that of S1 system. Lettuce crop (Cherokee RZ and Starfighter RZ) have given maximum yield in broken tile and minimum yield in hydroton in both S1 and S2 systems during the first and second seasons. 8-10mm gravel was found to be more favorable for the growth and yield of tomato (Yakamoz RZ and Manulakshmi) than all other media selected for the study. In all the cases, the plants grown in the dutch buckets filled with 75 % portion of gravel and wick inserted buckets filled with 75 % portion of gravel showed better performance than the buckets filled with 50 % portion of gravel. The performance of the plants grown in dutch buckets and wick-inserted buckets of S2 system was superior to S1 system. The overall result showed that tomato grown in 8- 10mm gravel and lettuce grown in broken tiles of S2 system showed better performance than all other media of S1 and S2 systems. The macro and micro nutrient level in the water of S2 system was found to be higher than that of S1 system during the study period. The benefit cost ratio obtained while cultivating tomato and lettuce in S2 system was more than that of S1 system. Considering the economic benefits, trouble free and easy operation, S2 system can be recommended for the aquaponics farmers of Kerala. 2024-01-01T00:00:00Z http://localhost:8080/xmlui/handle/123456789/1828 SOIL EROSION AND SEDIMENT YIELD ASSESSMENT OF KUNTHIPPUZHA SUB-WATERSHED USING SWAT AND RUSLE FATHIMA FARSANA; Anu Varughese The two essential fundamental natural resources for the existence of life are soil and water. Soil erosion is an environmental crisis in the world today that threatens the natural environment and also agriculture. Erosion removes the top fertile soil, degrades soil fertility, water quality and soil productivity. Almost 119.2 M-ha area out of 328 M-ha of geographical area is severely eroded in India (NBSS & LUP, 2005). The soil erosion risk assessment is helpful for land evaluation in the regions where soil erosion is a major threat for sustainable agriculture. Field studies for prediction and assessment of soil erosion are expensive and time-consuming. Soil erosion models are able to take into account many of the complex interactions that affect the rate of soil loss or erosion and are capable of simulating erosion processes in watersheds. There are several types of models like empirical, semi-empirical, and physical models. One of the extensively used empirical models to forecast soil erosion caused by water loss is the Revised Universal Soil Loss Equation (RUSLE) model. Among different physical models, Soil and Water Assessment Tool (SWAT) is widely used to predict soil erosion and sediment yield in the watersheds. The main objective of the study was to find the water balance components, soil erosion and sediment yield of Kunthipuzha sub-watershed using SWAT, soil erosion and erosion prone areas using RUSLE and to compare model results with observed data and to estimate the Sediment Delivery Ratio (SDR). SWAT model was simulated for a period of 32 years (1990-2021). Global sensitivity analysis of the model was done using the Sequential Uncertainty Fitting (SUFI-2) algorithm in SWAT-CUP. SWAT model was calibrated for discharge as well as sediment yield. The calibration was done for the period of 21 years from 1990 to 2014, and validation was done for a period of 3 years from 2015 to 2017. Nash Sutcliffe Efficiency (NSE) and R² for the calibration period was 0.77 and 0.86, and for the validation period it was 0.75 and 0.81 respectively for discharge. In case of sediment yield, NSE and R² for the calibration period were 0.79 and 0.88, whereas for the validation period it was 0.76 and 0.82 respectively. During the years of study, the outflow from the watershed is mainly in the form of surface runoff (ranges between 43 to 54%) and ground water flow (24 to 34%).From the soil erosion estimation using RUSLE and SWAT models, average annual soil loss was estimated to be 8.865 and 8.1 t ha −1 y −1 respectively. Sediment yield estimated from the outlet (Sub-basin 27) is 3.9 t ha −1 y −1 . Both in RUSLE and SWAT, major area of the basin is in slight erosion category (5-10 t ha −1 y −1 ). In SWAT, sub-Basins 2, 3, 4 and 7 in the North-eastern region comes under very severe erosion category (> 40 t ha −1 y −1 ). Since most of the watershed (around 70% area) comes under slight erosion category, soil erosion can be controlled by practicing agronomical measures. In the moderate erosion risk areas (around 9.35%), contour bunds and terraces are suggested. The SDR obtained for the entire watershed was very low (0.01 to 0.036), which indicate that even though more amount of soil gets eroded from some of the sub-basins, it gets deposited at intermediate locations before reaching the Pulamanthole gauging station. Analysis using both the models shows that the North-Eastern area of the watershed (Mannarkkad, Pottasserry, Puthupariyaaram etc.) experience more erosion, and hence more soil conservation measures need to be adopted in this region. Both models gave similar trend of spatial variation of soil erosion qualitatively and quantitively and less deviation from the observed sediment data. The result obtained is helpful for giving recommendations for proper soil conservation measures in the area. 2023-01-01T00:00:00Z