Effect of different fertilizers of secondary, micro- and beneficial elements on soil pH and Cd availability under waterlogged condition.

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.