Agricultural Water Management Practices and Environmental Influences on Arsenic Dynamics in Rice Field

Abstract

Rice plant cultivation around the world requires huge volume of fresh water, and depending on the soil constituents and enrichment profiling of elements present, uptake of metal(loid)s varies. Arsenic (As) predominates in its inorganic form in the soil system and gets altered in concentration of bioavailable fraction depending on various soil physico-chemical parameters and water application strategies used for rice cultivation. There is a proven correlation between different irrigation management processes and arsenic dissolution and mobility dynamics in soil system. Ferrous-manganese oxyhydroxides, phosphate, sulphur, silicate, and different soil organic matter (OM) compositions affect soil-As release from bound fractions in soil. Active microbial biomass, radial oxygen loss, and redox changes along with pH can potentially alter the plant available fraction of As in soil. With seasonal variation, irrigation practice applies several strategies of water management like continuously flooded, periodical irrigation, intermittent flooding, and sprinkler dripping and involves different field designs like permanent raised bed or occasional raised bed. As a way to nutrient-enriched rice cultivation, pisciculture in paddy field is also in practice. This chapter aims to discuss all the possible irrigation practices for rice cultivation alongside the soil environmental conditions that either triggers faster dissolution of As or hinders the mobility of being bioavailable.