S And As Accumulation And Distribution In Rice(Oryza.sativa L.) And The Change Of Their Speciation In Soil

A pot experiment was carried out to investigate the influence of different forms of sulfur fertilisers(sulphur and gypsum) and exogenous arsenic-polluted on dry matter weight of different parts of rice indifferent growth stage, concentration of Fe and Mn plaque in rice in different growth stages,concentration of S in different parts of rice in different growth stage, concentration of root surfaceadsorption As in rice, concentration of As in different parts in rice growth stage, concentration ofdifferent speciation S in different parts of rice in different growth stages, concentration of differentspeciation S in different parts of As contaminated rice in different growth stages. The main results wereas follows:1. Uncontaminated soil solution pH value ranged for7.17~7.28in different growth period of rice,soil solution ORP changed between210mv and230mv. Both pH value and ORP of S1and S2weremore than that of S0treatment. As-contaminated soil solution pH value was little higher than that inuncontaminated soil solution, but ORP declined. As-contaminated soil solution pH value ranged for7.38~7.45in different growth period of rice, and pH value of AsS0and AsS1were higher than AsS2treatment. As-contaminated soil solution ORP approached200mv, and ORP of AsS0was higher thanthat of AsS1and AsS2treatment.2. S-fertilizer could improve the quality of dry matter in root and stem and grain ofuncontaminated rice, and sulfur treatment was better than gypsum treatment. Exogenousarsenic-pollution could prominently reduce the quality of dry matter in rice. S-fertilizer could reducethe impact of As, and S-fertilizer applied by sulphur was better.3Fe plaque was confirmed to dominate Fe-Mn cutan in rice, and Mn plaque occupied only asecond place. S-fertilizer could promote the formation of Fe-Mn plaque in uncontaminated rice root,and elemental S treatment can promote more than gypsum treatment. Exogenous arsenic-pollutioncould enhance more Fe-Mn plaque. S-fertilizer could promote the formation of Fe-Mn plaque inAs-contaminated rice root, and S-fertilizer applied by gypsum was better.4. Amounts of S uptake in roots and stem and leaf and grain were enhanced by S fertilizer applied.Amounts of S in As-contaminated rice were higher than that in uncontaminated rice. S-fertilizer appliedby gypsum was better than sulphur in both uncontaminated and As-contaminated rice.5. Amounts of As adsorbed by rice roots surface plaque rised in tiller stage, and than reducedsharply in the other stages. As a whole, S-fertilizer could reduce the amounts of As adsorbed by riceroots surface plaque, sulfur treatments and gypsum treatments were not significant.6. Amounts of As uptake in roots and stem and leaf and grain were significantly reduced by Sfertilizer applied, and S-fertilizer applied by gypsum was better.7. In both uncontaminated and As-contaminated soil, the bioavailability of S declined. Organicsulfur was confirmed to dominate total sulfur in soil, and inorganic sulfur occupied only a second place.Inorganic sulfur given priority to water solubility sulfur and acid-soluble sulfur. S-fertilizer couldenhance the amounts of total sulfur, organic sulfur, inorganic sulfur and the proportion of effective sulfur, S-fertilizer applied by sulphur was better. After exogenous arsenic-polluted, the amounts of totalsulfur, organic sulfur and inorganic sulfur declined, the proportion of noneffective sulfur rised.S-fertilizer could partly inhibit the poison harm of As, and S-fertilizer applied by gypsum was better.8. S-fertilizer could effectively reduce the bioavailability of As in soil. S-fertilizer applied bysulphur could partly enhance the poison harm and bioavailability of As in early stages, than declinedslowly. S-fertilizer applied by gypsum could promote more As to unavailable ones.