Precise field experiments were established at 3 sites with oilseed rape under different soil-climatic conditions in the Czech Republic (Humpolec, Hněvčeves and Uhříněves) in the years [2008][2009][2010]. In this experiment, four fertilizing treatments with increasing S rate were evaluated. The contents of bioavailable (S W ), adsorbed (S ads ), occluded (S ocl ), and hydroiodic acid (HI) reducible (S HI ) sulfur were measured. The contents of the fractions within the studied sites in the samples collected before fertilizers application were comparable. The S W , S ads a S ocl contents did not exceed 10 mg S/kg. The S HI contents differed depending on site and year. Fertilizing using S as CaSO 4 positively influenced the contents of S W , S ads , and S HI in soil. Sulfur fertilizing had also the positive tendencies to increase the winter rape yields but the differences between studied treatments were not statistically significant.

The experiment was carried out to observe the influence of the CULTAN method (controlled uptake long term ammonium nutrition) on grain yield and yield formation of spring barley cultivar Jersey. In four-year small-plot experiment under conditions of the Czech Republic, two methods of nitrogen fertilization were used: conventional surface fertilization and local fertilizer injection rich in ammonium into soil during vegetation at BBCH 29-30 stages. Furthermore, the impact of sulphur amendment in fertilizer and increased dose of fertilizer were observed. Basic dose of nitrogen was 80 kg N/ha, increased dose 130 kg N/ha. At CULTAN treatment, same or significantly higher grain yields were obtained compared to conventional nitrogen fertilization. Grain yield at CULTAN fertilization is formed mainly on the main stem because of reduced tillering; it has the impact on significantly higher percentage of grain retained on 2.5 mm sieve. A tendency to lower protein content in grain was recorded at local injection of fertilizer compared to conventional fertilization. CULTAN-treated plants showed a lesser dependency of qualitative parameters on fertilizer dose and sulphur amendment in fertilizer. A positive influence of the CULTAN method on yield and quality of grain was observed mainly at the less fertile site.

Glomalin is one of the factors with an important role at forming and stabilising soil aggregates. Long-term stationary experiments were carried out to observe the influence of various fertilisation treatments on the content of glomalin in topsoil. The content of easily extractable glomalin (EEG) and total glomalin (TG) were determined. Moreover, glomalin was also determined by using the near-infrared reflectance spectroscopy (G_NIRS). Both mineral and organic fertilisation significantly increased the content of glomalin compared to the unfertilised control. However, observed differences among individual fertilisation treatments were not significant. A significant correlation was determined between the content of EEG, TG, G_NIRS, and the content of humic substances as well as humic acids. Both methods used (EEG, TG) can equally reflect soil organic matter quality. A significant correlation was also recorded between the G_NIRS and extraction methods (EEG, TG).

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 (S w ), adsorbed (S ads ), 1 mol/L HCl estimated (S HCL ) 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 S HCL . Application of SS increased the S w content in soil samples after potatoes harvest, whereas a decreasing tendency among the following crops was visible. Contents of other S forms (S w at control, FYM and mineral fertilizers included) were usually balanced during the crop rotation.

Soil carbon transformation was observed in long-term stationary field experiments (longer than 20 years) at two sites with different soil-climatic conditions (Luvisol, Chernozem). The following crops were rotated within the trial: row crops (potatoes or maize)-winter wheat-spring barley. All three crops were grown each year. Four different fertilization treatments were used: (a) no fertilizer (control); (b) sewage sludge (9.383 t dry matter/ha/3 years); (c) farmyard manure (15.818 t dry matter/ha/3 years); (d) mineral NPK fertilization (330 kg N, 90 kg P, 300 kg K/ha/3 years). At the Luvisol site, the control treatment showed a tendency to decrease organic carbon (C_org) in topsoil. At organic fertilization treatments the content of C_org increased: sewage sludge – +15.0% (Luvisol) and +21.8% (Chernozem), farmyard manure – +19.0% (Luvisol) and +15.9% (Chernozem). At the NPK fertilization, the increase was +4.8% (Luvisol) and +4.7% (Chernozem). The increased C_org content was also associated with an increase of microbial biomass carbon (C_mic) and extractable organic carbon (0.01 mol/L CaCl₂ and hot water extraction). The ratio of C_mic in C_org was within the range 0.93–1.37%.