Straw, particularly cereal straw, is a valuable by-product of crop production, which can be used for various purposes, e.g. as livestock feed and bedding or for making fuels, however it should primarily be retained on farmland in order to prevent soil organic matter (SOM) losses and thus to maintain or improve soil quality. The aim of this study was to analyze effects of the frequency of crop residues (straw) incorporation into the soil on the content of soil organic matter and on crop yields. There were the following experimental treatments: SR – straw of all crop in the rotation removed, S1 – straw of one crop per rotation incorporated, S2 – straw of two crops in the rotation incorporated, and S3 – straw of three crops incorporated into the soil (loamy sand). After 21 years of crop rotation with straw removal (SR) the SOM level in the soil slightly decreased to 14.4 g∙kg ^–1 soil DM, compared to that in 1997 (14.6 g∙kg ^–1). However, when straw of one crop (rape) per rotation was incorporated (S1) the content of SOM increased to 15.0 g∙kg ^-1 soil DM, and to 15.6 and 16.0 g∙kg ^–1 in S2 and S3 treatments respectively. Straw retention had also a beneficial effect on the content of labile fractions of SOM (hot water extractable C and N). Grain yields and yield components of wheat and triticale, and seed yields of rape in the SR treatment were not significantly different from those obtained in S1, S2 and S3 treatments.

The main aim of this study was to determine the morphology, physical and chemical properties of permafrost-affected soils under different types of tundra in the central part of Spitsbergen. This is a preliminary part of detailed studies focused on the relationship between tundra vegetation and permafrost-affected soils in the Spitsbergen. The obtained results indicate that all the studied soils represent an early stage of formation and the main soil-forming process present in these soils is cryoturbation. Most of the studied soils are shallow and contain a high content of coarse rock fragments. Tundra vegetation type plays controlling role in the development and structure of surface soil horizons. All the studied soils are characterized by loamy texture and acidic or slightly acidic reaction, and these properties are not very different under various tundra vegetation types. The contents of soil organic matter are strongly dependent on the type of tundra vegetation. The highest soil organic matter content occurs at sites with well-developed vegetation such as heath and wet moss tundra. The high carbon-to-nitrogen ratio for the surface soil horizons of the majority of the studied soils indicates that organic matter is poorly decomposed under all the studied tundra vegetation types. This is most likely related to low activity of soil microorganisms in the harsh High Arctic environment. However, the lowest carbon-to-nitrogen ratio was noted for surface soil horizons at sites covered with Arctic meadow, and this indicates that there occur the optimum conditions for soil organic matter decomposition.

Straw is a valuable by-product of crop production which can be used for various purposes (livestock feed and bedding, bioenergy). However, it should primarily be retained on farmlands to prevent soil organic matter (SOM) losses. Straw retained on the field is usually incorporated into the soil when conventional (with ploughing) and reduced tillage systems are used or left on the soil surface (mulching) when a no-tillage system is practiced. The aim of this study was to determine how different straw management practices (straw removal, straw incorporation and straw mulching) affected the incidence of Cephalosporium gramineum on two winter wheat cultivars, the grain yield of these cultivars and selected soil properties based on a long-term micro-plot experiment. Cephalosporium stripe disease was absent or occurred at very low levels (0–2.4%) when straw was removed or incorporated every second year. The disease was most severe, 24–33% tillers infected, in the SM(N) treatment with yearly straw mulching and cv. Bogatka was more tolerant to C. gramineum infection than cv. Bamberka. Importantly, yearly straw incorporation into the soil in contrast to straw mulching resulted in low disease levels (5–8% tillers infected) in both cultivars. Only in the case of cv. Bamberka was the grain yield significantly reduced in the SM(N) treatment compared to other treatments. The soil in this experiment contained the lowest level of soil SOM, which amounted to 21.0 g ∙ kg ^–1 soil dry matter (DM), when each year wheat straw was removed (SR). Straw incorporation every second year resulted in 24.2 g of SOM ∙ kg ^–1 soil and the largest amounts of SOM (26.0–26.1 g ∙ kg ^–1 soil) were found with yearly straw incorporation into the soil. Yearly straw mulching was inferior in this respect and the soil in this treatment contained 23.8 g of SOM ∙ kg ^–1 soil DM.