Evaluating of soil sulfur forms changes under different fertilizing systems during long-term field experiments

Abstract

The aim of this work was to evaluate the changes of different soil sulfur forms during long-term field experiments supplied with sewage sludge (SS), farmyard manure (FYM) or mineral fertilizers. The experiment was established at three different sites with the crop rotation of potatoes, wheat and barley. Fertilizing system was based on the same nitrogen dose per the whole crop rotation. Soil samples from the beginning of the experiment (1996) and at the end of each crop rotation were analysed after all three crops harvest. Similar tendencies of changes in water extractable (Sw), adsorbed (Sads), 1 mol/L HCl estimated (SHCL) sulfur and their sum of (∑S) related to the fertilizing systems were observed among all studied sites. A decreasing tendency of ∑S in soil was observed during the experiment (except for the year 2005). The biggest decrease was always visible compared to control treatment. Mineral fertilizers (S added with superphosphate) appeared to be the best source of SHCL. Application of SS increased the Sw content in soil samples after potatoes harvest, whereas a decreasing tendency among the following crops was visible. Contents of other S forms (Sw at control, FYM and mineral fertilizers included) were usually balanced during the crop rotation.

Keywords

• plant nutrient
• fertilization
• sulfur fractions
• sulfur deficiency
• essential element