After-effects of long-term tillage and residue management on topsoil state in Boreal conditions

Abstract

Abstract It is known that all processes in soil act in close interdependence and are site- and soil-specific, and climate and human activity dependent. Numerous studies have been done worldwide on soil structural composition, soil organic carbon (SOC) sequestration and soil CO2 efflux investigation, although most of published results were obtained in conditions different from the soil type, texture and climate conditions in the Nemoral-2 environmental/Boreal climatic zone. The effects of long-term tillage treatments on soil properties are seldom reported in Boreal conditions. The objective of this study was to assess the subsequent long-term cumulative effects of 17 years of conventional (CT) and no-tillage (NT) in combination with straw removal or return, on SOC accumulation, soil pore-size distribution (PSD), water release characteristics (WRC) and CO2 efflux on loam and sandy loam within a 0–10 cm layer of Cambisol during the main development stages of winter wheat. A more pronounced superiority of NT over CT for SOC sequestration rate within the topsoil layer emerged on loam than on sandy loam. The total volume of transition and storage pores, which is responsible for better soil water movement, was higher in sandy loam then in loam and under NT than under CT. However, a higher retention of topsoil moisture during the main growing stages of winter wheat was on loam than on sandy loam. Straw on loam acted as a material for soil loosening by increasing the total volume of fissures, transition and storage pores. Meanwhile, on sandy loam, the straw acted as a pore clogging material by decreasing the total volume of the same pores. Consequently, on loam, in spite of a high capability of NT with residue return to storage plant available water (PAW), the topsoil moisture during dry weather conditions at the main growing stages of winter wheat was lower than under other soil management practices. On sandy loam, NT with residue returning governed the highest PAW content and maintained the highest topsoil moisture. Nevertheless, the highest potential to reduce CO2 efflux on both loam and sandy loam has been demonstrated by CT with residue return.