淹水条件下不同中微量元素及有益元素对土壤pH和Cd有效性的影响

Effect of Different Fertilizers of Secondary,Micro-and Beneficial Elements on Soil pH and Cd Availability under Waterlogged Condition

本试验的目的是研究土壤淹水培养条件下不同中微量元素及有益元素对土壤pH和镉(Cd)有效性的影响,为Cd污染土壤中中微量元素及有益元素的合理施用提供技术支撑。结果表明,不同中微量元素和有益元素对土壤pH和Cd有效性的影响存在显著差异。淹水后,土壤pH由6.4迅速上升至7.0,维持一段时间后缓慢回落,60 d时降至6.7;土壤Cd的有效性经历了与pH变化相反的变化过程。Ca2+、Mg2+、S、硅酸钠和碳酸钙等能显著降低土壤中有效Cd含量,而Zn2+、Cu2+和Fe3+能显著增加土壤有效Cd含量。因此,建议在镉污染土壤种植水稻时,宜施用碳酸钙,硅酸钠和含硫肥料,慎重使用铜肥和锌肥。如果必须施用这些元素时,应把用量控制在生产推荐量以下。

The objective of this study was to investigate effects of different fertilizers of secondary,micro-and beneficial elements on soil pH and Cd availability under waterlogged condition and offer technology to properly use these elements in the Cd polluted soils.Results indicated that different fertilizers significantly affected soil pH and Cd availability.As the soil was flooded,soil pH rose rapidly from 6.4 to 7.0,maintained for a period of time and then dropped down to 6.7 at 60 d,while the soil Cd availability underwent a reverse change.Ca2＋,Mg2＋,S,sodium silicate and calcium carbonate were highly effective in reducing amounts of Cd extracted,while the micro-elements of Zn2＋,Cu2＋ and Fe3＋significantly increased the extractable Cd.Thus,the authors suggest that when making fertilizer recommendations of secondary,micro-and beneficial elements to the Cd polluted soils in rice growing season,sodium silicate and S bearing materials were most preferred while use of Cu and Zn should be cautious by strictly controlling its rates following recommendations.