Influence of Potassium Fertilizer on the Phytoavailability of Cadmium
钾肥对镉的植物有效性的影响

A field pot experiment was conducted to study the influence of potassium fertilizer(K_2SO_4) on the phytoavailability of Cd in soils with single stress of Cd and combined stress of Cd and Pb.Results showed that the application of K fertilizer could significantly(p<0.05) increase the dry weight of wheat and alleviate the toxicity of Cd and Pb.K fertilizer with different levels could decrease the uptake of Cd in wheat and the Cd phytoavailability in soils.With the increase of K fertilizer levels added,Cd contents and the enrichment coefficients of Cd in different parts(root,haulm and grain) of wheat decreased gradually at first and increased later.It was suggested that at the K2 level,K fertilizer would alleviate the Cd toxicity efficiently.And the application of K fertilizer would reduce the exchangeable fraction of Cd in rhizosphere and bulk soils.It was also illustrated in this work that the contents of exchangeable and carbonate Cd in soils were affected most by the application of K fertilizer.However,the contents of Fe-Mn oxide,organic and residual Cd in soils were less affected.Comparing combined treatment of Cd and Pb with single treatment of Cd,Pb application would increase the uptake of Cd in wheat and the Cd phytoavailability in soils.