Browsing by Author "Rema, K P"

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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 P
Studies 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.
Design and evaluation of a horizontal filter unit for ground water recharge through abandoned tube well
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2016) Jomol Joseph, T; Rema, K P
The groundwater table is declining at an alarming rate and it is essential to replenish the dried out aquifers by adopting proper artificial recharge methods. Field experiment on the design and evaluation of a horizontal filter unit for groundwater recharge through abandoned tube well was conducted in the research field of Nodal Water Technology Centre, College of Horticulture, Vellanikkara. The specific objectives of the study were to design and develop a horizontal filter unit with alternate filter media for treating storm water runoff, and to evaluate the developed filter for hydraulic and pollutant removal efficiencies. Suitability of the tube well for recharging and availability of adequate amount of source water were analysed in the primary stages of study. The peak runoff expected from the area was computed and compared with the carrying capacity of the existing conveyance channel. Thus the existing channel was modified and a masonry structure with a filter unit for treating runoff and a recharging section was constructed. The filter unit had five compartments filled with Gravel, Sand, Charcoal, Synthetic fibre and Coir fibre combinations as treatments, T1: Gravel, Sand, Coir fibre, Gravel; T2: Gravel, Sand, Synthetic fibre, Gravel; T3: Gravel, Charcoal, Sand and Gravel. Three sets of length variation in three different media combinations were selected as factors, F1: 80 cm, 80 cm, 80 cm, 80 cm; F2: 80 cm, 100 cm, 60 cm, 80 cm; F3: 80 cm, 60 cm, 100 cm, 80 cm Inflow and outflow water quality was analysed for evaluating filter hydraulic and pollutant removal efficiencies in simulated and actual runoff conditions. Treatment T1F1 was better in pH normalising efficiency, T1F2 removed Nitrate and Sulphates effectively, T1F3 was better in Total hardness and Calcium removal efficiency, T2F1 performed well for Magnesium and Chloride removal efficiencies. Treatments T2F2 and T3F3 were effective for EC, TDS, Salinity, TSS, Turbidity, Acidity, Fluoride, Alkalinity, Iron removal and Hydraulic efficiencies. 135 The Gravel (80 cm), Charcoal (100 cm), Sand (60 cm) and Gravel (80 cm) combination was selected as best filter media combination and it was installed in the field for recharging. With an average annual rainfall of 2795 mm in the study area, a runoff depth of 1118 mm can be expected. Accordingly a runoff volume of 2.3 million litres of water can be diverted from the study area to the recharge well annually. Comparison of this enormous benefit from the artificial recharge structure with the cost incurred is indicating the promising future of the artificial recharge schemes. If the abandoned open wells and tube wells in Kerala are utilised as recharge wells, a large quantity of water can be recharged annually and it will improve the groundwater potential of the state for future benefits.
Design flood estimation of Pazhassi barrage for effective management of floods
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology , Tavanur, 2024-01-06) Rukmini, R.; Rema, K P
Grey water treatment by constructed wetland
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2007) Abhijeet Hindurao Surve; Rema, K P
Infilitration and water advance studies under surage flow furrow irrigation
(Department of Land and Water Resources and Conservation Engineering, Kelappaji College of Agricultural Engineering and Technology,Thavanur, 1993) Rema, K P; Xavier K Jacob
Furrow irrigation necessitates the wetting of only a part of the surface of land, thus reducing evaporation losses, lessening the puddling of heavy soils and making it possible to cultivate the soil sooner after irrigation. Surge irrigation in furrows possesses the capability to increase irrigation efficiency, by ensuring water saving, better uniformity and reduced tail water losses in different soil and site conditions. To assess the suitability of the system for use in the sandy loam soils of Tavanur region, and to obtain suitable management parameters for surging in the area, a study was conducted at the Instructional Farm of KCAET, Tavanur. Continues flow was compared with surge flow of cycle ratios ½, 1/3 and 2/3 with cycle times 6.9 and 7.5 minutes for discharges of 1.3, 1.7, and 2.1 lps. Data of advance time, depth of flow and inflow-outflow measurements were collected during field irrigation runs. Surge flow in all cases advanced faster compared to continuous flow. For cycle ratio ½ the reduction in advance time ranged as 14.59, 22.8 and 14.77 per cent for the three discharge rates. In the case of cycle ratio 1/3, the reduction was 37.6, 41.94 and 38.01 per cent respectively, whereas for cycle ratio 2/3, the reduction was 34.29, 32.83 and 22.73 per cent respectively. Infiltration variability was lesser under surge flow and the values of infiltrated volume and infiltrated depth at various sections along the furrow length was lesser. Surging with cycle ratio 1/3 and a discharge of 1.3 lps showed the least variability in infiltrated depth and the greatest uniformity of application. Infiltration rate was found to decrease significantly along the length of the furrow and between consecutive surges. The lowest intake rate was obtained for surge flow of cycle ratio 1/3. Surging with cycle ratio 1/3, and a discharge of 1.3 lps required only 1.11 m3 of water to complete the advance. This was the least value compared to continuous flow and other surge flow cases. Analysis of variance of the volume required to complete the advance indicated significant difference between flow types at 5 per cent and 1 per cent levels. The variation between discharges was also significant at 5 per cent and 1 per cent levels. Thus surge flow proved advantageous compared to continuous flow in the sandy loam soils of Tavanur region and surging with cycle ratio 1/3 and a discharge of 1.3 lps was chosen as the best out of the selected treatments for the study.
Modelling soil erosion using rusle and GIS for Kadalundi river basin
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology ,Tavanur, 2024-02-12) Akhina, P; Rema, K P
Soil is the uppermost layer of the earth surface. All life on earth depends on soil, but at present soil degradation is increasing at an alarming rate and the principal reason for this is soil erosion. Erosion is a noticeable intrinsic natural process, but in many places it is increased by anthropogenic activities. Erosion assessment has a major role in deciding the proper land management measures. To overcome the limitations of conventional erosion assessment methods, researchers usually go for modelling. Empirical models like USLE and RUSLE are widely used for soil erosion prediction. However, soil erosion always results in sedimentation and empirical models do not account for sediment deposition. A comparison of estimated soil erosion and observed sediment yield can be done with the help of a SRC and SDR. The main objective of the study was to model the potential average annual soil loss from Kadalundi river basin using RUSLE and to map the spatial distribution of soil erosion hazard using GIS to suggest suitable soil conservation and management protocol for the basin and compare the results with sediment yield data from outlet gauging stations. The morphometric characteristics of the basin were analysed under linear, areal and relief aspects to assess the erosion vulnerability of the basin. Soil erosion in the basin was estimated by RUSLE model and spatial distribution map was generated. The SRC for high flow, low flow and medium flow conditions were plotted for the basin by using the sediment yield data and stream flow data collected from CWC gauging station, Karathode for 21 years. The SDR was calculated for the Kadalundi basin using the sediment yield data from CWC gauging station, Karathode and soil erosion estimated by RUSLE. Erosion field studies were conducted at Anakkayam region of Kadalundi river basin. Sediment sampling for Kadalundi river was done at Chittathupara gauging station for one year (November 2021 to December 2022) to estimate the sediment yield. The SRC was plotted for Anakkayam region. By using sediment yield data estimated by sediment sampling and soil erosion estimated for Anakkayam region for 2021 by RUSLE model the SDR was computed. The depth of soil lost was also measured by using erosion pins installed in two trial plots of at ARS, Anakkayam. The zonal statistics was calculated for slope and land use with respect to soil erosion, to suggest suitable soil conservation and management protocol for the basin. The overall results of morphometric analysis revealed that the basin is erosion prone. The average annual soil erosion estimated by RUSLE for Kadalundi basin is 5.48 t•ha-1•yr-1 and 5.92 t•ha-1•yr-1 for Anakkayam region. Majority of the area of basin and Anakkayam region falls under slight erosion class (40 t•ha-1•yr-1). The SRC developed for high flow, low flow and medium flow can be used for future predictions of sediment yield for similar conditions. The SDR for Kadalundi basin and Anakkayam region were 0.10 and 0.98 respectively, which indicates sediment deposition is high for Kadalundi basin and very low for Anakkayam region. Erosion pin results indicate the mean depth of soil lost during one year, for a slope of 32 per cent is 18.4 mm and 16 per cent slope is 16.4 mm. Since larger part of the basin is having slight erosion, most of the erosion problems can be controlled by simple agronomical measures. Bunds, trenches and terraces were suggested to the areas having moderate erosion and slope stabilization and drainage line treat ments can mitigate the erosion problems in the areas in severe and very severe erosion classes in the basin.
Modelling the impact of land use land cover changes on the runoff processes of Chalakudy basin using HEC-HMS model
(Tavanur Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, 2020) Nchumbeni M Odyuo; Rema, K P
Fast development of urbanization alongside other expanding anthropogenic factors have been distinguished as significant reasons for land use changes and land transformations. This eventually causes several devastations like floods, droughts, water contamination and soil debasement. There is a need for target evaluation and investigation on the land utilization patterns and the mode of operation of water conserving structures in order to take up any preventive and additional healing measures. The state of Kerala in particular is notable for significant level of development as far as socio–monetary components, education, human services and so forth are considered. The broad financial changes have prompted expanded pace of framework, building development and several land use changes in the most recent decade. Evaluating the spatial and temporal changes in land use and land cover (LULC) of a basin is one of the analytic strategies to comprehend the issues continuing in a basin and gives significant understanding of its effect on runoff processes. The Chalakudy river basin in Kerala was one of the worst affected basins during the floods of 2018 and has experienced unaccountable damages to human life, ranches, gardens, domesticated animals, buildings, roads etc. The present study compares the LULC changes over two different decades 1997- 2007 and 2007-2017 by analysing the LULC maps and the effect of these changes on the runoff processes in Chalakudy river basin. From the LULC maps, the area under each class, the percentage area coverage and decadal percentage change for each class were calculated. The Hydrologic Modelling System HEC-HMS, developed by the US Army Corps of Engineers Hydrologic Engineering Centre (HEC) was used to model the flood flows of the basin. Calibration and validation of the model was done by employing the SCS CN as the loss method. Calibration of the model was done for five years (2003- 2007) to discover the best parameters of HEC-HMS model while validation of the model was done for three years (2015- 2017). The final analysis of the model showed CN to be the most sensitive parameter for simulating the runoff in the basin. The Nash-Sutcliffe model efficiency (E) for the calibration period was found to increase from 0.726 to 0.766 and 0.816 for the validation period. The correlation coefficient (R2) value was observed to increase from 126 0.80 to 0.83 before and after the calibration and a value of 0.85 was obtained for the validation period respectively indicating good performance of the model. Simulation runs of the model were done separately for another three years i.e., 1997, 2007 and 2017 in order to analyze the changes in runoff with respect to land use changes. It was observed that the vegetation area decreased consequently from 886.21 km2 to 803.09 km2 while the urban area was found to increase from 31.74 km2 to 41.93 km2 (1997-2017). Aside from that the annual rate change for each class was calculated and results showed an increment in the class of paddy, palm, barren land and urban area while a decrease in annual rate change of vegetation class was also observed. LULC transition matrix was also prepared for 1997-2007 and 2007-2017. From the net loss and gain calculation it was observed that the highest loss from 1997-2007 was found to be for vegetation (-52.52 km2) and the highest gain was of Paddy (54.39 km2). In between 2007-2017 the highest loss was noticed to be for vegetation (-30.59 km2) while the highest gain was for barren land (54.39 km2). The study highlights a disturbing observation in the last two decades and how this change has prompted the occurrence of floods and runoff. After analyzing the decadal land use changes and the simulated runoff values, it was understood how, loss of vegetation cover and increase in urbanization being the most significant reasons for LULC changes have altered the overall basin ecology.
Soil loss estimation and spatial mapping using rules and GIS-A case study in Kurumanpuzha sub watershed of Chaliyar river basin
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, 2022) Aishwarya, M S; Rema, K P
Land degradation is a problem of grave concern and one major factor leading to it is soil erosion. The main aim of the study is to calculate the soil loss in the sub watershed. This study also analysed the quantitative analysis of morphometric parameters of Kurumanpuzha sub watershed using remote sensing data and geographic information system. Morphometric parameters were evaluated from three perspectives: Linear, Areal and relief characteristics. A fifth-order river drains Kurumanpuzha watershed and the drainage network is mainly dendritic type. The mean bifurcation ratio (Rb) was 2.05. The watershed has elongated shape suggesting low peak flows for longer duration and hence easier flood management. The drainage texture analysis revealed fine drainage which implies the dominance of impermeable soft rock with low resistance against erosion. High relief and steep slopes dominates, by which rough landforms (hills, breaks, and low mountains) make up major portion of the watershed. The hypsometric curve with hypsometric integral of 0.48 suggests that Kurumanpuzha watershed is in equilibrium or mature stage of geomorphic evolution. At sub-watershed scale, the derived morphometric parameters were grouped into three clusters (low, moderate, and high) and considerable spatial variability was observed. The results of this study provide information on drainage morphometry that can help better understand the watershed characteristics and serve as a basis for improved planning, management, and decision making to ensure sustainable use of watershed resources. Soil erosion is caused by the action of various factors which are intrinsic to the soil or related to the environment surrounding the soil. These factors include rainfall, soil erodibility, topographic characteristics, crop cover and conservation practices. The Revised universal soil loss equation (RUSLE) is a well-renowned empirical formula which is used to compute the average annual soil loss of a particular area. Remote sensing (RS) and geographical information system (GIS) technologies make modelling and execution of RUSLE easy, reliable and cost effective. So, these were employed to compute the spatial distribution of soil erosion risk area in Kurumanpuzha sub watershed in Kerala state, India. All the factors were generated using metrological data, CartoSat DEM, Landsat 8 imagery using GIS software and integrated in a GIS environment to estimate the soil loss rate. It was found that forest/Dense vegetation 142 (56.46%) was the dominant land use followed by rubber plantation (20.06%) and o scrub land (8.91%). The average annual soil loss of the watershed was estimated to be 8.00 t ha-1 yr-1 and the total quantity of soil eroded was 82,872.4 t yr-1 . The average annual soil loss was highest in bare land (8.55 t ha-1 yr-1 ) followed by scrub land (5.27 t ha-1 yr-1 ). The soil erosion map thus generated can serve as a basis for adopting suitable measures in the watershed for sustainable management of the resources in it.
Soil loss estimation and spatial mapping using rules and GIS-A case study in Kurumanpuzha sub watershed of Chaliyar river basin
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology,Tavanur, 2022-05-24) Aishwarya, M S; Rema, K P
Land degradation is a problem of grave concern and one major factor leading to it is soil erosion. The main aim of the study is to calculate the soil loss in the sub watershed. This study also analysed the quantitative analysis of morphometric parameters of Kurumanpuzha sub watershed using remote sensing data and geographic information system. Morphometric parameters were evaluated from three perspectives: Linear, Areal and relief characteristics. A fifth-order river drains Kurumanpuzha watershed and the drainage network is mainly dendritic type. The mean bifurcation ratio (Rb) was 2.05. The watershed has elongated shape suggesting low peak flows for longer duration and hence easier flood management. The drainage texture analysis revealed fine drainage which implies the dominance of impermeable soft rock with low resistance against erosion. High relief and steep slopes dominates, by which rough landforms (hills, breaks, and low mountains) make up major portion of the watershed. The hypsometric curve with hypsometric integral of 0.48 suggests that Kurumanpuzha watershed is in equilibrium or mature stage of geomorphic evolution. At sub-watershed scale, the derived morphometric parameters were grouped into three clusters (low, moderate, and high) and considerable spatial variability was observed. The results of this study provide information on drainage morphometry that can help better understand the watershed characteristics and serve as a basis for improved planning, management, and decision making to ensure sustainable use of watershed resources. Soil erosion is caused by the action of various factors which are intrinsic to the soil or related to the environment surrounding the soil. These factors include rainfall, soil erodibility, topographic characteristics, crop cover and conservation practices. The Revised universal soil loss equation (RUSLE) is a well-renowned empirical formula which is used to compute the average annual soil loss of a particular area. Remote sensing (RS) and geographical information system (GIS) technologies make modelling and execution of RUSLE easy, reliable and cost effective. So, these were employed to compute the spatial distribution of soil erosion risk area in Kurumanpuzha sub watershed in Kerala state, India. All the factors were generated using metrological data, CartoSat DEM, Landsat 8 imagery using GIS software and integrated in a GIS environment to estimate the soil loss rate. It was found that forest/Dense vegetation 142 (56.46%) was the dominant land use followed by rubber plantation (20.06%) and o scrub land (8.91%). The average annual soil loss of the watershed was estimated to be 8.00 t ha-1 yr-1 and the total quantity of soil eroded was 82,872.4 t yr-1 . The average annual soil loss was highest in bare land (8.55 t ha-1 yr-1 ) followed by scrub land (5.27 t ha-1 yr-1 ). The soil erosion map thus generated can serve as a basis for adopting suitable measures in the watershed for sustainable management of the resources in it.
Spatial mapping of flood prone areas and risk assessment of Chalakudy river basin using HEC-HMS and HEC-RAS models
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2021) Gudidha Gopi; Rema, K P
Floods are one among the most devastating natural disasters that affects life on the globe. For the planning and design of water resources projects in the preferred area, planners and engineers usually require reliable estimates of flood magnitude and frequency. Kerala state in the Indian sub continent received a catastrophic flood in the year 2018. The present study attempts to model the flood flows and map the flood prone areas of a river basin in Kerala. The Chalakudy river basin, one of the worst-affected river basins due to heavy rains and floods was selected for the present study. This is the fifth largest river in Kerala. The basin is predominant with agricultural land and falls under the humid tropical zone, where water resources planning and management is necessary for irrigation scheduling, flood control and design of various engineering structures. In order to address the above issues, an attempt was made to calibrate and validate HEC-HMS model for simulating the flood hydrograph for the Chalakudy river basin. Flood frequency analysis was carried out to estimate the flood peak values using frequency distributions in HEC-SSP software. The results were compared with the estimated flood peak values for different return periods obtained from the HEC-HMS model. Hydraulic routing was done in HEC-RAS model and the flood inundation maps were prepared. The cadastral level risk areas were identified based on water surface profiles of velocity and depth of flood extent and its characteristics. Food vulnerability maps based on land use patterns were developed in order to identify the severely affected land uses. The HEC-HMS model for the basin was developed using SCS-UH, SCS- CN, Recession and Muskingum methods to find out the loss rate, runoff transformation and routing of flood respectively. Statistical performance indices of the model, Nash-Sutcliffe efficiency (NSE) and Coefficient of correlation (R2) values were obtained above 0.7, Error in Peak Flow (%) and Error in Volume (%) were figured below 20% and Root Mean Square Error-Standard Deviation Ratio (RSR) was acquired as 0.5 and below. These values indicated that HEC-HMS model simulation performed well in both calibration and validation. Thefrequency discharge values calculated using Log Pearson type-III distribution indicated a high degree of similarity to the HEC-HMS generated values with an R 2 value of 0.862. The results of the Log Normal and Gumbel distributions are significantly lower than those of the HEC-HMS model values. The assessment of the vulnerability due to the flooding was made with regard to the land use pattern and cadastral level risk map of Chalakudy river basin was developed for different return periods. Kadukutty Panchayat located in the downstream of Chalakudy river basin was found to be the maximum flood inundated area for 10 year return period ( 557 ha) and for 200 year return period (681 ha). Manjapra Panchayat located in upstream was found to be the least flood inundated area for 10 year return period (6 ha) and for 200 year return period (9 ha). Annamanada, Kadukutty, Melur and Pariyaram panchayats were under high risk areas, with depths greater than 20 m. Ayyampuzha, Chalakudy, Mala, Kuzhur, Parakkadavu and Puthenvelikara panchayats were under medium risk areas with depths varying from 10 to 20 m. Athirappilly, Manjapra and Karukutty panchayats were under low risk areas with depths less than 10 m. The flood vulnerability maps were generated by intersecting the flood plain land use map with the flooded area polygons. Paddy land near to the river banks was found to be the highest inundated by different return period floods, followed by forest and other vegetation, barren land and other land use classes.
Studies on the effect of alternate growing systems and irrigation schedules for soilless culture of salad cucumber
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2015) Sabeena Shahul; Rema, K P
Field study on the effect of alternate growing systems and irrigation schedules for soilless culture of salad cucumber under drip irrigation was conducted inside the naturally ventilated polyhouse in the research plot of Precision Farming Development Centre, in the Instructional Farm of KCAET, Tavanur, during November 2013 to March 2014. In this study coirpith was the media used. The crop water requirement of salad cucumber was determined using CROPWAT model. The data on micro climate inside the polyhouse were periodically recorded on daily basis. The physico chemical and engineering properties of coirpith were studied. The experiment was laid out in a two factor completely randomized block design. The plot was divided into three rectangular sections with three treatments each replicated thrice. The treatments were F1T1 (Black poly bag with daily irrigation), F1T2 (Black poly bag with alternate day irrigation), F1T3 (Black poly bag with irrigation once in 3 days), F2T1 (Lay flat grow bags with daily irrigation), F2T2 (Lay flat grow bags with alternate day irrigation), and F2T3 (Lay flat grow bags with irrigation once in 3 days). Fertigation in coir pith include both macro and micro nutrients applied as water soluble fertilizers from two tanks (tank A and tank B) through fertigation system with venturi. Data about vegetative parameters for each treatment were observed during different stages of crop growth. The results on the effect of alternate growing systems used, irrigation frequency and their combined effect on crop growth and yield parameters were statistically analyzed. Analyzing the effect of alternate growing systems, it was found that vertical type growbag filled with coirpith showed better performance than lay flat type growbag. In case of irrigation interval, crops under once in three days irrigation showed better performance at the initial stage (winter season). But during mid-season (summer season) alternate day irrigation resulted in better growth and yield than once in three days irrigation. The highest yield was for F1T2 (7.56 kg/plant) followed by F1T1 (6.34 kg/plant). Irrigation interval significantly affected irrigation water use efficiency (IWUE). The highest IWUE was for F1T3 (2590 kg/ ha.mm) and lowest was for F2T1 (446.14 kg/ ha.mm). Even though crops under alternate day irrigation were identified with remarkable yield, once in three days irrigation can be suggested in the areas experiencing water shortage. The results of this experiment showed that it is possible to obtain satisfactory yields of hybrid cucumber Hilton variety grown under polyhouse conditions in coirpith filled vertical growbags. The study also revealed that crops with once in three days irrigation at initial stages followed by alternate day irrigation during mid-stage and late stage in vertical type growbag resulted in better performance. Using inert growing media like coirpith demands full fertigation with all macro and micro nutrients for good FUE.
Suitability of drip automation systems for optimal irrigation scheduling
(Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2015) Manasa, K; Rema, K P
Automation in irrigation management refers to those innovations which partially or fully replace manual intervention from watering operations. Automized irrigation includes automation at regional level or farm level. Recently, technological advances have been made in soil water sensors for efficient and automatic operation of irrigation system by which exact quantity of required water can be supplied to the crop. Automatic soil water sensor-based irrigation seeks to maintain a desired soil water range in the root zone that is optimal for plant growth.The present study was conducted to evaluate the suitability of drip automation systems for optimal irrigation scheduling. The field experiment was done in the rain shelter in the research plot of Nodal Water Technology Centre, College of Horticulture, Vellanikkara, during the months of October 2014–March 2015. The experiment was done for tomato variety Akshaya in rain shelter with 4 treatments of irrigation levels. The experiment was laid out in CRD with 3 replications. The main objectives of the study were to evaluate the performance of sensor based automated drip irrigation systems, scheduling irrigation for tomato based on the best performing drip automation system and to evaluate the cost economics of drip automation system with optimal irrigation scheduling. Irrigation was provided using sensors through drip automation system at 40 per cent, 50 per cent and 60 per cent moisture depletion levels (MDL) from the available moisture content. Control was irrigated at the rate of 2 l/plant/day. Crop growth parameters such as height of the plant, number of days to first flowering, number of days to initial budding, number of days to first harvest, root length and root dry weight were observed. During all the stages, plant height significantly varied in all treatments. All the parameters were found to be better in 50 per cent MDL treatment compared to other treatments. Yield parameters such as number of fruits and total yield were recorded. There was no significant difference in number of fruits per plant in all the treatments. Yield was significantly higher in 50 per cent MDL than that of other treatments. Water use efficiency was significantly different in all the treatments. WUE in T2 and T3 was on par which showed better performance than other treatments. The analysis of the data of soil moisture content at 2 and 6 hours after irrigation was monitored at distances of 0, 15 and 30 cm from the emitter laterally and at a depth of 0, 10, 20 and 30 cm from the surface. Soil moisture contour maps for the longitudinal section of the soil were plotted using computer software “Teraplot 1.3.02” version. The pattern was more uniform for T2 (50 per cent MDL) two hours after irrigation. Benefit cost (B/C) ratio for each treatment was calculated. The maximum benefit cost ratio of 2.57 was noted in T2. Hence it can be concluded that for tomato (Akshaya) grown in rain shelter, 50 per cent MDL can be fixed as the optimum level for scheduling irrigation. As 60 per cent moisture depletion also gave good yield and WUE on par with 50 per cent level, 60 per cent MDL can also be suggested for scheduling irrigation in water scarce areas.