秸秆和猪粪对小麦镉吸收的影响

Effects of Straw and Pig Manure on Uptake of Cadmium by Wheat

采用盆栽试验,以黄棕壤和潮土为供试土壤,每种土壤上按照有机碳加入量一致的原则设置5个处理,分别为对照(不添加有机物)、1.1%和2.7%秸秆处理、2%和5%猪粪处理,研究施用秸秆和猪粪对小麦Cd含量、土壤Cd形态、pH值、有机质组成的影响,为利用有机物调控小麦Cd污染提供科学依据。结果表明,施用秸秆和猪粪均可显著降低小麦各部位Cd含量。施用秸秆和猪粪均可促进土壤Cd由活性较强的交换态向其他形态转化。土壤交换态Cd含量与小麦Cd含量呈极显著正相关。秸秆对土壤pH值总体上无显著影响,猪粪可显著降低潮土pH值,增加黄棕壤pH值。施用秸秆和猪粪可使土壤胡敏酸(HA)与富里酸(FA)的比值HA/FA显著升高。土壤HA/FA与交换态Cd含量呈极显著负相关;土壤交换态Cd含量与pH值只有在猪粪施入黄棕壤的处理中呈极显著负相关,在其他处理中均呈正相关。综上,施用秸秆和猪粪均可通过促进土壤Cd形态的转化抑制小麦对Cd的吸收,其机制主要与土壤有机质组成和pH值有关。

The pot experiment was conducted in fluvo-aquic soil and yellow brown soil.Five treatments which contained equivalent total organic carbon were designed,which were CK,1.1% straw,2.7% straw,2% pig manure and 5% pig manure,and the effects of straw and pig manure on cadmium(Cd) content of wheat,Cd forms in soil,soil pH value and organic matter composition were analyzed,so as to provide theoretical basis for the use of organic materials to control Cd pollution of wheat.The results showed that the application of straw and pig manure significantly decreased Cd concentration of wheat.Both straw and pig manure could promote the transformation of exchangeable Cd with high activity to the other forms.There was significantly positive correlation between Cd content of wheat and exchangeable Cd content in soil.The effect of straw on soil pH value was not significant,but pig manure significantly decreased the pH value of fluvo-aquic soil,and increased the pH value of yellow brown soil.Both straw and pig manure significantly increased the ratio of humic acid(HA) to fulvic acid(FA) in soils.HA/FA of soils was significantly negatively with exchangeable Cd content.However,there was significantly negative correlation between soil pH value and exchangeable Cd content in yellow brown soil treated by pig manure,soil pH value was positively correlated with exchangeable Cd content in other treatments.Overall,the application of straw and pig manure could reduce the Cd content in wheat through the change of Cd forms in soils,and its mechanism was mainly related with the composition of organic matter and soil pH value.