科研之友
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摘要
The aim of this work was to estimate the changes in contents of different sulfur (S) fractions in soils under conditions of lowering inputs of S from emissions together with the influence of application of manure and mineral fertilizers. Soil samples from long-term field experiments were used for this purpose. The samples were taken from 10 sites from precise long-term field experiments with different soil-climatic conditions in the Czech Republic. The samples were analyzed using the following fractionation: (i) water soluble S (H(2)O extracts), (ii) sorbed S (0.032M NaH(2)PO(4) extracts) and (iii) S occluded with carbonates (IM HCl extract). Furthermore, the concentration of total S (S(tot)) and organic S (S(org)) was determined. Soil samples were taken in the years 1981 and 2007. During 26 years a decrease of S(tot) by about 3-8%, water soluble S by 65-68% and sorbed S by 39-44% were observed in the topsoil of the evaluated soils. Furthermore, a low increase in the content of organic S was observed. The estimated ratio of S(org) reached 78.7-80.9% from S(tot) in the year 1981 and 87.7-89.8% in 2007. Farmyard manure (40 t/ha) applied every 4 years did not have a significant influence on S fractions and S(tot) contents in soils; intensive S fertilizing increased S(tot) and mobile S forms contents in soils. Very close correlations were obtained especially between S(tot) and water soluble S and organic S.
- 出版日期2009-8
