Power Point Pr

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Element cycles in mountain regions in Korea under
different land use J. Kettering1 Y.
Kuzyakov1 1 University of Bayreuth Dept. of
Agroecosystem Research, Universitätsstraße 30,
D-95440 Bayreuth Janine.kettering_at_uni-bayreuth.de

Introduction and Research Aims 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. The International Research Group
TERRECO examines the way to carry out land
management in mountain regions, in order to
ensure sustainable yield of ecosystem services.
The higher goal of this project (T-8) within
TERRECO is to examine the influence of forest
conversion to agriculture on nutrient cycles at
the farm level as well as to reconstruct the
history of previous erosion and nutrient losses,
and attempt to define best agricultural
management practices.
Study Area The sites of the project are located
in the Haean Catchment in the central part of
Korea, just south of the demilitarised zone (see
Fig.23). The landscape of Haean Catchment
consists of three zones including deciduous
forest, dry land farming, and rice paddies (see
Fig.1). Intensive land use due to the low
percentage of flat land in Korea, high levels of
fertilisation together with extreme precipitation
during the summer monsoon can be found on-site.
Korean chemical fertilizer applications for
intensive agriculture are extremely high on a
worldwide scale, increasing from 230 kg/ha/yr in
1980 to 450 kg/ha/yr in 1994. Annual erosion of
topsoil may reach 40 cm year-1 (see Fig.67).
Therefore, the impacts on this mountainous
terrain are considered to be profound.

North Korea
South Korea
Lake Soyang
Haean Catchment
Seoul
Lake Soyang
Fig.1 Panoramic view of the study area, the
Haean Catchment, Yanggu Gun, South Korea Picture
Dr. Jan Fleckenstein, University of Bayreuth.
Fig.3 Satellite image of Korean Peninsula
indicating locations of Seoul and the Soyang Lake
Reservoir Red Mixed Forest Green Croplands
Fig.2 Map indicating the location of Haean
Catchment within the Lake Soyang Watershed
Fig.5 Cultivated area at slopes in Korea
(right),soil erosion during the summer monsoon
in Korea (left)Pictures Professor Jae E. Yang,
KNU, Chuncheon
Fig.4 Satellite (left) and terrain (right) image
of Haean Basin Sources left Google Earth 2009
right Google Maps 2009
Methods Research Plans for the 1st phase Field
Work In the initial phase of the study, the
focus of the field work will be put on estimation
of fertiliser budgets and on estimation of
fertilizer losses by runoff or leaching and their
outflow in aquatic systems. Calculations will be
based on specific crop areas, NPK input and NPK
withdraw by harvest. Another aspect of
investigation will be soil carbon dynamics in
soils under maize, using 13C natural abundance.
The approach 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 d13C
values of SOC. Laboratory work The methods of
our research are based on application of
isotopes 14C and 13C labelling. Goals of the
laboratory work focus on the analysis of organic
polymers locally used for soil stabilisation
against erosion by Prof. Yong Sik Ok. 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.
Experiment (1) Decomposition rates of organic
polymers Layout Incubation experiment under
controlled conditions Aims Evaluation of period
for which organic polymers have direct and
indirect effect on soil stabilisation Effects of
polymers on microbial mass, SOM decomposition and
C sequestration Prerequisite d13C of polymers
should be for at least 10 different from d13C of
the soils Analyses - total CO2 efflux from soil
(effect of polymers on SOM decomposition and C
sequestration) - d13C of CO2 (decomposition rate
of the polymers) - Microbial biomass by
fumigation/extraction method (FEM) - Aggregate
size, composition and stability (effect of
polymers on aggregate stabilization) Outlook
3-5 best polymers will be chosen for the
following experiments Collaboration - Prof.
Yong Sik Ok, Dept. of Biological Environ., KNU
polymers, soil aggregates, erodibility, C
sequestration - Prof. Taeseok Ahn, Dept. of
Environ. Science, KNU enzymes, DGGE of
microorganisms
Experiment (2)(3) Effect of polymers on
decomposition of plant residues Layout
Incubation experiment under controlled conditions
Aims Effect of these 3-5 best polymers on
decomposition of plant residues and their
incorporation into SOM and microbial biomass
Prerequisite 14C labelled plant residues will
be produced (maize and rice) Analyses - Total
CO2 efflux from soil (effect of polymers on SOM
decomposition and on plant residue
decomposition) - 14C of CO2 (decomposition
rate of plant residues) - Microbial biomass by
fumigation/extraction approach - 14C in
microbial biomass (incorporation of plant
residues into microbial biomass) - Enzyme
activities Collaboration - Prof. Yong Sik Ok
(see Experiment 1) - Prof. John Tenhunen, Dept.
Of Plant Ecology, UBT C budgeting in rice
Experiment (4) Effect of polymers on DOM
leaching and aggregate stability Layout Column
experiment Aims Effect of 2-3 polymers on soil
aggregation Effects of polymers on DOM leaching
Prerequisite Presence of DOM added on soil
surface (DOM will be labelled by
14C) Collaboration - Prof. Bernd Huwe, Dept. of
Soil Physics, UTB erosion experiments
Fig.6 Overview illustration of the integration
of Project 8 within TERRECO red DFG projects,
blue Korean projects Source Proposal for an
International Training Group 2009, available at
www.bayceer.uni-bayreuth.de/terreco/en/forschung/4
3708/65489/proposal.pdf
International Research and Training Group
TERRECO - Complex Terrain and Ecological
Heterogeneity http//www.bayceer.uni-bayr
euth.de/terreco/