A CENTURY 5 model using for estimation of soil organic matter behaviour at predicted climate change

The trends of carbon sequestration behaviour have been estimated for the most fertile soil type of Slovakia based on the prognosticated regional climate change scenario. The processes were modelled and simulated by the model CENTURY 5 to provide these inputs: predicted information about quantification of C and N fluxes, and primary net of organic matter production. Soil conditions were represented by calcareous Haplic Chernozem (Danubian lowland) and the climatic scenario was related to the meteorological station Hurbanovo modelled for the period of 2005−2090. The dynamics of soil C and N was assessed using a conventional cropping system modified into two alternatives: with fertilisation and without irrigation (ALT1); excluding fertilisation and irrigation (ALT2). The model CENTURY 5 provides the simulation of three soil organic matter (SOM) pools: the active (labile) pool (CL), the slow (sequestration) pool (CS), and the passive (resistant) pool (CP). The results of the model simulation predict that the supplies of CL and CS do not show any statistically significant decreasing tendency in relation to the expected climate scenario. A moderately linear decreasing trend is expected with CP, however, this decreasing tendency is not recognised during total C running. In the case of ALT1, the model shows a gradual but very moderate decrease mainly with CS pool, and in that of ALT2 a significant decreasing trend is recognised with all SOM pools, mainly with CS pool. Amazing is the finding that in the case of non-irrigated but fertilised cropping system, the anticipated significant decrease in C sequestration was not observed, however, more drastic changes can be predicted in the non-fertilised and non-irrigated alternative. The results of CENTURY 5 modelling assume that in the case of sufficient fertilisation and irrigation with well-managed cropping rotation practice under fertile soil conditions of Slovakia, no serious changes in C supplies can be expected.