Evaluation of groundwater quality and its suitability for drinking and agricultural use in Thanjavur city, Tamil Nadu, India

As groundwater is a vital source of water for domestic and agricultural activities in Thanjavur city due to lack of surface water resources, groundwater quality and its suitability for drinking and agricultural usage were evaluated. In this study, 102 groundwater samples were collected from dug wells and bore wells during March 2008 and analyzed for pH, electrical conductivity, temperature, major ions, and nitrate. Results suggest that, in 90% of groundwater samples, sodium and chloride are predominant cation and anion, respectively, and NaCl and CaMgCl are major water types in the study area. The groundwater quality in the study site is impaired by surface contamination sources, mineral dissolution, ion exchange, and evaporation. Nitrate, chloride, and sulfate concentrations strongly express the impact of surface contamination sources such as agricultural and domestic activities, on groundwater quality, and 13% of samples have elevated nitrate content (>45 mg/l as NO3). PHREEQC code and Gibbs plots were employed to evaluate the contribution of mineral dissolution and suggest that mineral dissolution, especially carbonate minerals, regulates water chemistry.Groundwater suitability for drinking usage was evaluated by the World Health Organization and Indian standards and suggests that 34% of samples are not suitable for drinking. Integrated groundwater suitability map for drinking purposes was created using drinking water standards based on a concept that if the groundwater sample exceeds any one of the standards, it is not suitable for drinking. This map illustrates that wells in zones 1, 2, 3, and 4 are not fit for drinking purpose. Likewise, irrigational suitability of groundwater in the study region was evaluated, and results suggest that 20% samples are not fit for irrigation. Groundwater suitability map for irrigation was also produced based on salinity and sodium hazards and denotes that wells mostly situated in zones 2 and 3 are not suitable for irrigation. Both integrated suitability maps for drinking and irrigation usage provide overall scenario about the groundwater quality in the study area. Finally, the study concluded that groundwater quality is impaired by man-made activities, and proper management plan is necessary to protect valuable groundwater resources inThanjavur city

Screening of chilli genotypes for drought tolerance

Chilli (Capsicum annuum L.) is an important solanaceous crop highly susceptible to drought due its higher transpiring leaf surface, high stomatal conductance and low membrane integrity. The pot culture experiment to screen the 12 chilli genotypes for drought tolerance was conducted with two treatments with 100 % field capacity as control and 50 % field capacity as drought and screening was done on the basis of various parameters. The overall results revealed that the tolerant genotypes maintained higher level of cell membrane integrity, chlorophyll stability, osmolyte accumulation and low lipid peroxidation under drought. Among the genotypes, CA 176 showed its supremacy by maintaining higher chlorophyll content, relative water content, cell membrane integrity and lower lipid peroxidation followed by CA 183 in its performance under drought. On the other hand CA 45, CA 104 and CA 174 showed poor performance by being very sensitive to water stress with very low yield

Study on gas exchange and antioxidant system of solanaceous species under water logged conditions

The aim of our work is to study gas exchange and antioxidant system in nine wild solanaceous species Solanum indicum, Solanum macrocarpon, Solanum acculeatissimum, Solanum sysimbrifolium, Solanum nigrum, Solanum viarum, Solanum insimum Solanum torvum, and Solanum macranthum under water logging condition. Experiments were laid in factorial completely randomized design with three replications. Photosynthesis and stomatal conductance decreased and closure of stomata was quick during flooding conditions in all the Solanum species. Species Solanum torvum performed photosynthetically better under flooding and also had better stomatal conductance. The antioxidants like SOD, catalase and peroxidase activity was significantly increased during the period of waterlogging and lipid peroxidation (MDA) content was decreased in tolerant Solanum species. An increase in the some parameters associated with oxidative stress, namely peroxides production, lipid peroxidation, and electrolyte leakage, reveals that root oxygen deficiency caused photooxidative damage in all rootstocks of solanaceous species. The ability to maintain a balance between the formation and detoxification of activated oxygen species appeared likely to increase the survival potential and the tolerance of the plants against varying oxidative stress. On basis of our observation, we conclude that species with higher photosynthetic rate and antioxidant system had improved waterlogging stress tolerance

Efficacy of Different Irrigating Systems on Debris and Smear Layer Removal: A Scanning Electron Microscopic Study

Background: The goal of this research was to see how effective various irrigation methods were at eliminating smear layer and debris. Study design: Sixty extracted single rooted human mandibular premolar teeth were used in this study. The root canals were shaped with a WaveOne large (040.08) rotary file after decoronating all the teeth to a uniform 16 mm root length. Root canals were rinsed with 6 ml of 2.5 percent sodium hypochlorite solution during instrumentation. After instrumentation, teeth were arbitrarily classified into four categories, each containing 15 specimens according to the technique of activation of final irrigant. Smear Clear solution (6 ml) was employed in all the categories as irrigating solution. In Group1- Rotary canal brush, Group 2 – EndoActivator, Group 3 – Passive ultrasonic irrigation (PUI), Group 4 – Continuous ultrasonic irrigation was employed. After sectioning the roots longitudinally, the apical, middle and coronal thirds of the canals were inspected with the help of scanning electron microscopy. Results: Group 4 was most effective in eliminating debris and smear layer at the coronal, middle, and apical thirds. But Group 4 was not significantly different to Group 3 at the middle third in eliminating debris and at middle third and apical third in elimination of smear layer. Conclusion: Continuous ultrasonic irrigation eliminated debris and smear layer most effectively, followed by PUI, EndoActivator, and Rotary canal brush. Keywords: Smear layer, Passive Ultrasonic Irrigation, Continuous ultrasonic irrigation, EndoActivator, Rotary canal brush</jats:p

Enhancement of Yield and Quality of Guava cv. Lucknow-49 by Foliar Application of Nutrients under High-Density Planting System

In view of the importance of foliar application of macro and micro nutrients to increase the yield and quality of guava under high density planting system, an experiment was laid out in a randomized complete block design consisting of nine treatment combinations with three replications. [(Control - Fertigation alone), (NPK (19:19:19)), (NPK + Zn), (NPK + Ca), (NPK + B), (NPK + Zn + Ca), (NPK + Zn + B), (NPK + Ca + B), (NPK + Zn + Ca + B). Among the treatments, fruit weight (225.22 g), fruit volume (215.35 ml),number of fruits per plant (80.35), fruit yield per plant(17.67 kg plant-1), TSS(10.60 0Brix), titratable acidity (0.196 %) and pectin content (1.31 %) was found to be significantly higher with the foliar application of NPK @ 1% + Zn @ 0.5 % + B @ 0.4%. The foliar spray of NPK @ 1% + Ca@ 0.2% + B@ 0.4% significantly increased the fruit diameter (7.85 cm), and ascorbic acid content (159.84 mg 100g-1). Thus, foliar spray of NPK, zinc and boron maintained more number of fruits per plant and improved the fruit set leading to an 18% increase in yield. Whereas, the addition of calcium to the plants increased the ascorbic acid content of the fruit and pectin that enhanced the shelf life of the fruit</jats:p