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Arsenic (As) contamination in rice and the deleterious effects of its consumption on human health is a major concern. To decrease the bioavailable fractions of arsenic in soil for achieving subsequently reduced accumulation of arsenic in rice grains, a pot experiment was conducted using arsenic-laden soil. The effects of different nutrient amendments viz., ZnSO4, FeSO4, Ca2SiO4, Murate of Potash (MOP), Di-Ammonium Phosphate (DAP) independently and in combination (as a mix) at low, mid, and high doses were evaluated concerning arsenic accumulation in rice variety Muktoshree IET-21845. Changes in bioavailable fractions of soil arsenic were measured by the sequential extraction procedure. The total arsenic in the control treatment without any amendment was 19 mg kg−1. The maximum concentration of total arsenic in grains in the control treatment without any amendment was 1.02 mg kg−1. It was found that the combined (mid-dose of the mix) amendments enhanced rice growth by 55%, and decreased arsenic accumulation in the grain by 89%, which was the minimum total arsenic reached with the suitable amendments. The bioavailable fractions of soil arsenic were decreased to 79% and 88% in the case of mid-dose application of the DAP and the mix (combined amendments) treatments to the soil, respectively. These nutrient amendments in defined doses may be highly effective in reducing arsenic toxicity to rice cropping in the arsenic-contaminated soils. [ABSTRACT FROM AUTHOR]

Excessive sodium content in sodic soils is an important limiting factor for cultivation of agricultural crops. The present study was conducted to explore the influence of a novel organic amendment (SFOA) along with use of plant-growth-promoting fungi (PGPF) on soil properties and growth/yield ofOryza sativaL. The combined application of PGPF and SFOAincreased total organic carbon (TOC) (0.62%) and decreased the exchangeable sodium percentage (ESP) (15.6%) of soil more significantly from 0.56% (TOC) and 30.1% (ESP), respectively compared to SFOAalone treatment. The combined application reduced soil bulk density, pH, and electrical conductivity (EC) and improved soil enzymatic activities. A significant negative correlation was observed between grain yield with soil ESP and bulk density (r = –0.728, and –0.789, respectively). This study showed that the combined treatment of PGPF and SFOAcould enhance the potential of organic amendments for alleviating salt stress in rice. [ABSTRACT FROM AUTHOR]

Immobilized biomass of novel indigenous fungal strains FNBR_3, FNBR_6, FNBR_13, and FNBR_19 were evaluated for arsenic (As) removal from aqueous solution. Alginate beads containing 0.1 g biomass were used in a batch experiment (200 mg l −1 As; pH 6). Biosorption equilibrium established in first 2 h with As adsorption (mg g −1 ) as 70, 68, 113 and 90 by FNBR_3, FNBR_6, FNBR_13 and FNBR_19, respectively. The equilibrium was fitted to the Langmuir model (r 2  = 0. 90-0.97). The absorption kinetic followed the pseudo second order. Changes in the surface of fungal cells and intracellular As-uptake by fungal biomass were also confirmed by scanning electron microscopy combined with X-ray energy dispersive spectrometer. The presence of different functional groups on fungal cells capable of As-binding was investigated by FTIR. The As-removal by immobilized fungal beads tested in the packed columns also. The As-adsorption by biomass (qe as mg g −1 ) were recorded as 59.5 (FNBR_3 and FNBR_6), 74.8 (FNBR_13), and 66.3 (FNBR_19) in the column and validated by Thomas model. This is the first report concerning the arsenic removal by immobilized biomass of these novel fungal strains from aqueous solution both in batch and column studies with a prospect of their further industrial application. [ABSTRACT FROM AUTHOR]