The leaching and retention of copper lignosulphonate, copper sulphate and copper-EDTA in soil

Authors

• Johan Korkman Kemira Oy, P. O. Box 330, 00101 Helsinki 10, Finland
• Pirkko Virta Kemira Oy, P. 0. Box 171, 90101 Oulu 10, Finland

DOI: https://doi.org/10.23986/afsci.72018

Abstract

In this work, a comparison is made between four soil types with respect to the leaching and retention of copper in them when it is added in the form of copper sulphate, copper lignosulphonate and copper-EDTA-chelate. In laboratory tests, the soil samples in lysimeter tubes were fertilised on the surface with amounts of copper corresponding to the amounts used in practice, after which the soils were irrigated with pure water. The results showed that copper added in EDTA form was leached through the soil columns to some extent during irrigation when the pH values of the soils had been raised to the 7.0—7.4 level by the addition of lime. The copper added in the form of copper lignosulphonate or copper sulphate was not leached through the columns. There was no difference in the distribution of copper in the soil columns after eluviation where the different sources of copper were concerned. The bulk of the copper remaining in the soil was found in the uppermost stratum 2.5 cm in depth. There was no difference between the four soil types in this respect. When the soil was analyzed immediately after eluviation, the copper retained in it was still in an acetate-EDTA extractable form irrespective of source compound.