Determination of phytotoxic soil aluminium by electroultrafiltration

The experiments address the questions of whether phytotoxic Al can be determined by electroultrafiltration (EUF). Spring barley (Hordeum vulgare) was grown in pot experiments on 28 soils differing widely in their characteristics. Al toxicity was measured in terms of root parameters and top growth. On soils rich in EUF extractable Al typical Al toxicity symptoms were found in roots and tops. EUF extractable Al obtained at the cathode (EUF-Al, cathode) was correlated with root fresh weight (R² = 0.554), root length (R² = 0.653), root diameter (R² = 0.729) and fresh weight of tops (R² = 0.681). The Al obtained at the anode was not correlated with any of these plant parameters. It is supposed that this anionic Al consists of non toxic organic Al complexes. Correlations between plant parameters and KCl-exchangeable Al were less close than those for EUF-Al (cathode). Correlations between soil pH and plant parameters were in between the correlations for exchangeable Al and EUF-Al (cathode).