Abstract: Apot experiment with winter wheat (Triticum aestivum) and calcareous soils collected fromNorthern China Plain shows that there is no significant correlation between SB/Dor AB/Dextracted Cu and Cu uptake by wheat plant, indicating that these two extractants are unsuitablefor testing soil available Cu. But SB/D-extrated Cu is correlated with Cu uptake at level P<0.01 and can be used to evaluate soil available Cu, when soil pHvalue and orgnic matter content are calibrated. The higher the soil pHvalue, the less the Cu uptake by wheat. The averagc soil available Cu is decreased 19μg per pot, when pHvalue is increased one unit. When thesoil pHvalue and the soil organic matter content are increased, the content of soil available Cu isdecreased and increased respectively.

Key words: Soil available Cu, Soil chemical properties, Cu uptake effect, Winter wheat, carbon capture and storage, carbon sink, material flow analysis, lime, missing carbon sink