FeSO4/lime mixtures - an alternative to mineral sulfur and lime fertilizer for summer rape

Sulfur (S) is one of six important macronutrients and due to the strong reduction of atmospheric S, it has to be fertilized to cover the S demand of plants – especially of those with a high S demand. In addition to regular S fertilizers, FeSO4 × 7 H2O was tested as a compound for a new S fertilizer. A pot experiment was conducted in order to test if FeSO4 × 7 H2O, a by-product in TiO2 production from ilmenite (FeTiO3), can be used in mixtures with limestone (CaCO3) or hydrated lime [Ca(OH)2] as an S fertilizer for summer rape (Brassica napus L). The results showed that S fertilization in the form of FeSO4 × 7 H2O/lime mixtures resulted in the same effects on the S and phosphorus (P) availability to summer rape as a gypsum/CaCO3 mixture. Application of S as FeSO4 × 7 H2O/lime mixtures resulted in the same seed yields of summer rapes as compared to S application as a gypsum/CaCO3 mixture. These results indicate that FeSO4 × 7 H2O/lime mixtures can be used as a combined mineral S and lime fertilizer.