水稻遭受砷的毒害作用,比旱土作物敏感得多,这是熟知的事实。在淹水土壤的还原条件下,通气性土壤中的不溶性砷酸铁被还原成为易溶性的亚砷酸亚铁。亚砷酸亚铁对一般生物为害大。因此,在淹水土壤中,砷的可溶性和毒害作用同时增大。士壤中的铁化物此之砷化物多得多。并且Fe~(?)与Fe~(?)达到平衡状态的氧化还原电位比之砷酸与亚砷酸达到平衡状态的氧化还原电位高。因此,在砷酸被还原成为亚砷酸的同时,高铁已经被还原成亚铁;结果是土壤溶液中Fe~(?)增多。据报道,亚铁对水稻有毒害作用;水 It is a well-known fact that rice is poisoned by arsenic much more sensitively than dryland crops. Under flooded soil reduction conditions, insoluble iron arsenate in aerated soil is reduced to readily soluble ferrous arsenate. Ferrous arsenite is very damaging to most organisms. Therefore, in flooded soils, the arsenic solubility and poisoning effects increase at the same time. There is much more arsenic in ferric oxide in soil. In addition, the oxidation-reduction potential at equilibrium of Fe ~ (?) And Fe ~ (?) Is higher than the oxidation-reduction potential of arsenate at equilibrium with arsenious acid. Thus, while arsenic is reduced to arsenious acid, high-speed iron has been reduced to ferrous iron; as a result, there is an increase in Fe ~ (?) In the soil solution. It is reported that ferrous iron has a toxic effect on rice; water