Organic soils that had been drained in order to obtain fertile agricultural land underwent changes leading to the formation of mursh (also known as moorsh). The mursh-forming process is a generic soil process that occurs in drained (artificially or naturally) organic soils, and leads to the changes in soil morphology, soil physical properties (including water retention capability), physicochemical properties, and chemical and biological properties. The aim of the paper is to present scientific knowledge on mursh soils, especially those that are not available to the wider audience. We firstly reviewed scientific literature on the mursh (moorsh) forming process of drained organic soils used for agriculture. We described the specific character of organic soils, differences between mursh and peat, the origin of the mursh-forming process, and the classification of organic soils (Histosols). Additionally, we described the changes in organic matter, such as the loss of soil carbon, increase of availability of plant nutrients, and leaching of biogens to groundwater. We revealed that the mineral matter in organic soils can be an indicator for distinguishing various types of murshes. We have highlighted the current gaps in the research that need to be filled in. The mursh-forming process is inherently related to the mineralization of soil organic matter and leads to a reduction of organic carbon in soil. Mursh has many unfavorable properties with regards to agriculture and environmental management. These properties are mainly related to decreased water storage capacity, which significantly limits the hydrological function of organic soils. The use of drained organic soils is a trade-off between environmental quality and agricultural production.

Doi:10.3906/tar-1402-66 Effects of peat drainage on labile organic carbon and water repellency in NE Polan

The size of peat subsidence at Solec peatland (Poland) over 50 years was determined. The field values for subsidence and mineralization were compared with estimates using 20 equations. The subsidence values derived from equations and field measurements were compared to rank the equations. The equations that include a temporal factor (time) were used to forecast subsidence (for the 20, 30 and 40 years after 2016) assuming stable climate conditions and water regime. The annual rate of subsidence ranged from 0.08 to 2.2 cm year⁻¹ (average 1.02 cm year ⁻¹). Equation proposed by Jurczuk produced the closest-matching figure (1.03 cm year⁻¹). Applying the same equation to calculate future trends indicates that the rate of soil subsidence will slow down by about 20% to 0.82 cm year⁻¹ in 2056. With the measured peat subsidence rate, the groundwater level (57–72 cm) was estimated and fed into equations to determine the contribution of chemical processes to the total size of subsidence. The applied equations produced identical results, attributing 46% of peat subsidence to chemical (organic matter mineralization) processes and 54%—to physical processes (shrinkage, organic matter consolidation). The belowground changes in soil in relation to groundwater level have been neglected lately, with GHGs emissions being the main focus.