Faculty Publications
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Item Effect of hydraulic conductivity on soil moisture uptake under saline conditions for wheat crop(2013) Devatha, C.P.; Ojha, C.S.P.; Hari Prasad, K.S.; Thalla, A.K.Salinity in soil can decrease plant available water and cause plant stress. The pattern of root water uptake for wheat was studied for saline as well as non-saline condition using non-linear root water uptake model. Experiments have been conducted using a salinity level of 4 dS/m and freshwater condition. The effect of salinity on soil moisture has been studied by varying the crop coefficient as well as hydraulic conductivity. The correction factor to the crop coefficient approach is found to be unsuccessful. However, the correction factor to the hydraulic conductivity for a non-saline condition improves the simulation of soil moisture uptake in case of saline soils. The exponential form of the equation is established for the hydraulic conductivity to soil moisture relationship under salinity level and freshwater sample. The present work also substantiates that the non-linearity parameter of root water uptake model (O-R model) is successful in simulation of soil moisture depletion in the crop root zone and does not vary more than 10% in case of saline soils. © 2013 Indian Society for Hydraulics.Item Assessment of soil moisture uptake under different salinity levels for paddy crop(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Devatha, C.P.; Shankar, V.; Ojha, C.S.P.The core of salinity problems starts from the fact that irrigation waters contain some amount of dissolved salts. Soil moisture salinity is dependent on soil type, climate, water use, and irrigation. The root water-uptake pattern for paddies is studied for saline as well as nonsaline conditions in the present study using a nonlinear root water uptake model. Field crop experiments are carried out using irrigation water with two different levels of salinity (4 and 6.25 dS=m) and fresh water. The effect of salinity on soil moisture uptake is studied by two approaches, i.e., effect on crop coefficient and effect on hydraulic conductivity. Based upon the experimental observations for lowsaline (4 dS=m), high-saline (6.25 dS=m), and freshwater conditions, an exponential form of an equation is established for the hydraulic conductivity. The results obtained for soil moisture depletion in the crop root zone show significant improvement in prediction of soil moisture uptake for saline cases with the use of the obtained nonlinearity parameter. © 2016 American Society of Civil Engineers.Item Investigation of physical and chemical characteristics on soil due to crude oil contamination and its remediation(Springer Verlag, 2019) Devatha, C.P.; Vishnu Vishal, A.; Purna Chandra Rao, J.Oil contamination causes serious geoenvironmental concern and adversely affects the soil environment due to the release of toxic by-products. Hence, the aim of the study was to investigate the influence of oil contamination on soil physical and chemical properties and phytoremediation as a treatment option based on field studies conducted for analyzing significant parameters. The sites selected were near National Institute of Technology, Surathkal, Karnataka (site-1), and another is close to the oil refinery (Kuthethur, Karnataka, India, as site-2). Phytoremediation of oil-contaminated samples was carried out by Chromolaena odorata. The evaluation of soil physical and chemical properties includes field and laboratory tests. A pumping test was conducted to estimate aquifer parameters in the field. The hydraulic conductivity for field soil sample (unsaturated condition) is carried out by a filter paper test. Laboratory tests to evaluate physical and chemical parameters include total petroleum hydrocarbons of contaminated (crude oil varying from 0 to 10% at an interval of 2%) and uncontaminated samples and plant parameters. Characterization of contaminated and uncontaminated soil sample was performed by Fourier transform infrared (FTIR) spectroscopy. The results obtained reveal that physical properties of soil (moisture content, liquid and plastic limit) got affected due to oil contamination. Relative hydraulic conductivity was established as 0.46 (uncontaminated) and 0.57 (contaminated) for soil samples and led to the conclusion that hydraulic conductivity was drop down by 10% due to oil contamination. Total petroleum hydrocarbon analysis reveals that the uptake/presence of hydrocarbons by showing increased concentration in contaminated soils (5% and 10%) by the plant species. This is further confirmed by FTIR results. The TPH concentrations in the contaminated soils were reduced up to 50–60% and also showed better plant growth after 7 weeks of transplantation. Hence, considered plant species possess high potential for degrading oil contaminated in the soil. © 2019, The Author(s).Item Investigation on phosphate transport mechanisms in laterite and laterite clay soils and its immobilization: Mining region(Elsevier Ltd, 2025) Bincy, B.; Devatha, C.P.; Thalla, A.K.Phosphate contamination from mining regions has significantly affected soil strata and groundwater quality. This study examines the transport mechanisms and adsorption behaviour of phosphate in laterite soil (LS) and laterite clay soil (LCS) and the effectiveness of various laterite clay mixtures (LCM)— bentonite (LB), kaolinite (LK), and zeolite (LZ)—in enhancing its adsorption and immobilization. The survey indicated that 60 % of wells were no longer used due to chemical contamination (66 %) and acid leakage (34 %). Additionally, 82 % of people rely on industry-supplied water for drinking, emphasizing the impact of contamination on well usability. A 3D unconfined aquifer model, incorporating LS and LCS soil basins, field-equivalent soil properties, and well conditions, was used to analyse phosphate transport under real-world conditions. The aquifer model indicated a gradual increase in phosphate concentration within wells, peaking at 6.50 ppm and 5.60 ppm in wells 2 and 3, respectively. Batch adsorption, XRD, and SEM analysis were performed to study the adsorption kinetics and surface morphology of LS and LCS under varying concentrations. Findings show that LCS has a higher adsorption capacity than LS (Kd-187.10, 2.40 L/kg, and KL -290.77, 22.32 L/kg), and Freundlich adsorption isotherm (FRI) further confirmed it (Kf-158.69 and 16.80 L/kg). Immobilization analyses showed that the LB mixture exceeded LK and LZ, with a maximum adsorption capacity (Kf) of 86.5 L/kg compared to kaolinite (71.4 L/kg) and zeolite (49.9 L/kg). The findings emphasize bentonite as the most suitable for contaminant immobilization with laterite soils in the study area. © 2025