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The prevalence of hydrogen fluoride (HF) toxicity in rice plants with visible foliar injury was observed in rice fields in the vicinity of an aluminium smelter in Odisha, India. The crop was damaged up to 2.5 km from the aluminium smelter by the atmospheric transportation of fluoride (F) under the influence of the prevailing wind and rain. Plants growing nearer to the smelter (1 km) were exposed more to the fluoride toxicity, resulting in reduced vegetative growth with a reduction in the total dry matter production and a light green colour due to a lower chlorophyll content. The grain yield of the plants with chronic fluoride toxicity was reduced by 53.7%. The grain yield increased as the distance from the smelter increased indicating that the industrial F pollution persisted in the study area. The F content in the leaves of the rice plants at a distance up to 2.5 km from the smelter was higher (95.8±28.6 ppm) than the threshold limit of 30 ppm. The F content in the upper layer of the soil within 3 km from the smelter varied from 83.3±0.7 to 203.1±5.9 ppm. The F content in water at 1 to 2 km from the smelter was higher (1.7±0.6 to 3.7±0.9 ppm) than the threshold limit of 1.5 ppm, whereas from 2.5 to 3 km from the smelter, it was within the 1.5 ppm standard (0.6±0.3 to 0.8±0.4 ppm). The range of the F concentration in the rice grains was 0.3±0.1 to 1.4±0.9 ppm with those collected from 2 or more km from the smelter having a F content that was lower than the threshold limit of 1.0 ppm. The F-containing emissions of the aluminium smelter were considered to be the likely cause of the F accumulation and the pollution of the soil, plants, and water in the vicinity of the aluminium smelter. [ABSTRACT FROM AUTHOR]

Tritium concentration in different parts of the rice plants, grown in villages around Tarapur Atomic Power Station, west coast of India, exposed to continuous atmospheric tritium in field condition were studied during two harvesting seasons of the years 2016 and 2017. The TFWT (HTO) and OBT concentrations in different parts of the rice plants were determined along with tritium in soil and air. The HTO to OBT concentration ratio in rice and hay was greater than unity in majority of the samples. [ABSTRACT FROM AUTHOR]

The suitability of seven chemical extractants was evaluated on 24 Indian coastal soils for prediction of plant-available potassium (K) to rice (Oryza sativa L. var. NC 492) grown in modified Neubauer technique. Average amounts of soil K extracted were in descending order: 0.5 M NaHCO3 > neutral 1 N NH4OAc > 0.02 M CaCl2 > Bray and Kurtz No.1 > 1 N HNO3 > 0.1 N HNO3 > distilled water. The highest simple correlation with plant K uptake was obtained with 0.1 N HNO3-K (r = 0.848) and lowest with CaCl2-K (r = 0.805). Predictive models were developed using plant K uptake as the dependent variable and extractable soil K, sand, silt, soil pH, and electrical conductivity as the independent variables. Based on the final R2 and ease of measurement, distilled water, 1 N NH4OAc, and 0.1 N HNO3 models were the best predictors of plant-available K in coastal soils when used along with sand or soil pH. [ABSTRACT FROM AUTHOR]