Abstract
The objective of this study was to evaluate effects of long-term mineral–organic fertilisation on the dynamics of arylsulphatase (EC 3.1.6.1) activity, the enzyme taking part in the mineralisation of sulphur compounds in soil. The soil under study was sampled in 2001–2004 three times over the vegetation period, at the beginning, in the middle and just before harvest. Plants were cultivated in the crop rotation: potato, winter wheat, spring barley and maize. The split-plot experiment was carried out as a two-factor one (fertilisation with cattle farmyard manure in five doses and fertilisation with mineral nitrogen in four doses). Samples were analysed for carbon of organic compounds, total nitrogen and pH in KCl, according to commonly used methods. Arylsulphatase activity was assayed according to Tabatabai and Bremner, and sulphates as described by Bardsley–Lancaster and modified by COMN-IUNG. Sulphur was abundant in this soil, and therefore the plants should be well supplied with this element. The highest arylsulphatase activity and sulphates (VI) content were found in the case of fertilisation with 60 t · ha−1 farmyard manure. Significant correlations were noted between the parameters under study.