Study of the Suitability of Selected Extractants for Determination of Plant-Available Arsenic in Some Inceptisols of West Bengal, India

Abstract

A study was conducted to assess the suitability of extractants for soil-available arsenic (As) under kharif rice (MTU-7029). Ten soil samples were collected from different locations of varying topography and land-use patterns from Nonaghata-Uttarpara of West Bengal. A pot study with MTU-7029, exposed to varying levels of arsenic (0 to 90 mg kg−1 of soil), was conducted for two successive years. Eight extractants, namely sodium bicarbonate (NaHCO3), ammonium acetate (CH3COONH4), monopotassium phosphate (KH2PO4), hydrochloric acid (HCl) + sulfuric acid (H2SO4), ammonium carbonate [(NH4)2CO3], sodium hydroxide (NaOH), malic–citric acid, and ethylenediaminetetraacetic acid (EDTA), were assessed. Soil test and crop uptake correlations revealed that 0.5 M NaHCO3 was the best extractant. In a lateral study, three soils were collected from a conventional rice field of Nonaghata-Uttarpara, Gotera, and Ghentughachi of West Bengal and sequentially extracted. The results showed that the relative abundance of As fractions were in the order of water-soluble As < Ca As < Al As < amorphous Fe As < crystalline Fe As.