Element Cycles in mountain regions in South Korea under various land use
2 Dept. of Biological Environment, Kangwon National University
P 1.14 in Funktion von Ökosystemen
During recent decades, land use has been changing worldwide, and impacts on ecosystems have significantly increased. While crop production is considered desirable, negative effects include high inputs of nutrients, greater erosion rates, removal of nutrients and carbon in harvests and decreases in the quality of SOM. The strongest impacts occur in mountainous landscapes. Hence, the mountainous sites of the project are located in the Haean Catchment in the central part of Korea, just south of the demilitarised zone. Intensive land use with high levels of fertilisation together with erosion during the summer monsoon can be found on-site. In the initial phase of the study, the focus of the field work will be put on fertiliser budget as well as on soil carbon dynamics in soils of the Haean Catchment. Therefore, collecting data, mainly from the stakeholder, selecting appropriate sites in the agricultural area and collecting samples are required first. As a tracer method for the estimation of C input into the soil by plants we will use 13C natural abundance. The method is based on the discrimination of 13C isotopes during CO2 assimilation by plants with different photosynthesis types. Therefore, by growing a C4 plant on soils with former C3 vegetation, the amount of C4 plant derived C can be estimated on the basis of the changing δ13C values of SOC. The goals of the laboratory work focus in the first year on the work with organic polymers locally used for soil stabilisation against erosion. Experiments include analysing the degradation of these polymers as well as their effects on microbial mass, SOM decomposition and C sequestration. Afterwards, 3-5 polymers will be chosen and in following experiments tested both for their effect on decomposition of plant residues and for their incorporation into SOM and microbial mass. Finally, another experiment will deal with the question of the effect of polymers on DOM leaching and aggregate stability. As tracer methods 13C natural abundance as well as 14C labelling will be used.