Application of selected nutrient amendments to regulate soil properties for reducing arsenic accumulation in rice

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.