Spatial Modeling of Nitrogen Leaching
51
Nevertheless, EPICINT can be used as an instrument for consulting purposes.
Once the database is built up and the model calibrated for a region, each
interesting single area can be investigated on different question formulations,
including alterations in irrigation volume, crop rotation, cover crops, and use of N
fertilizer.
EPICINT is rather easy to handle, and with few instructions any user can run
simulations.
5 Summary and Conclusions
The integration of database, empirical models, and user interface in a GIS
platform can simplify decision-making, especially for spatial problems. The
application ,EPICINT' is an easy-to-use tool to model nitrogen leaching to
groundwater within large areas. By running multiple scenarios, the best way to
reduce pollution can be found.
The empiric model shows the results of two variants of crop rotation for the
community of Markgrafneusiedl. The simulation was run over 20 years. Medium
values of nitrate concentration, nitrogen leaching and percolation over this period
of time were shown.
Adding cover crops and green fallow to crop rotation can reduce nitrogen
leaching to groundwater, in particular on soils with a low plant-available water
capacity.
With spatial knowledge of soils and crop rotation, modeling can be done on
larger areas. A transfer to other regions may come along with new field
measurements and validation.
Once the entire data are available for a region, detailed consulting in definite
fields for mUltiple crop rotations can be done.
Notation
hI
fraction of the storage PO occupied by percolation water ()
CN03
N03 concentration in water (g m· 3 )
Fe
field capacity (33 kPa for many soils) water content (mm)
HU
daily heat units - average daily temperature minus base temperature of
crop (0C)
HUI
heat unit index - ratio of accumulated to potential heat units (0-1)
LAI
leaf area index - area of plant leaves relative to the soil surface ( )
a
percolation rate (mm d· l )
PHU
potential heat units for crop maturity (0C)
PO
soil porosity (mm)
Q
runoff volume (mm)
QR
lateral flow rate (mm d· l )
51
Nevertheless, EPICINT can be used as an instrument for consulting purposes.
Once the database is built up and the model calibrated for a region, each
interesting single area can be investigated on different question formulations,
including alterations in irrigation volume, crop rotation, cover crops, and use of N
fertilizer.
EPICINT is rather easy to handle, and with few instructions any user can run
simulations.
5 Summary and Conclusions
The integration of database, empirical models, and user interface in a GIS
platform can simplify decision-making, especially for spatial problems. The
application ,EPICINT' is an easy-to-use tool to model nitrogen leaching to
groundwater within large areas. By running multiple scenarios, the best way to
reduce pollution can be found.
The empiric model shows the results of two variants of crop rotation for the
community of Markgrafneusiedl. The simulation was run over 20 years. Medium
values of nitrate concentration, nitrogen leaching and percolation over this period
of time were shown.
Adding cover crops and green fallow to crop rotation can reduce nitrogen
leaching to groundwater, in particular on soils with a low plant-available water
capacity.
With spatial knowledge of soils and crop rotation, modeling can be done on
larger areas. A transfer to other regions may come along with new field
measurements and validation.
Once the entire data are available for a region, detailed consulting in definite
fields for mUltiple crop rotations can be done.
Notation
hI
fraction of the storage PO occupied by percolation water ()
CN03
N03 concentration in water (g m· 3 )
Fe
field capacity (33 kPa for many soils) water content (mm)
HU
daily heat units - average daily temperature minus base temperature of
crop (0C)
HUI
heat unit index - ratio of accumulated to potential heat units (0-1)
LAI
leaf area index - area of plant leaves relative to the soil surface ( )
a
percolation rate (mm d· l )
PHU
potential heat units for crop maturity (0C)
PO
soil porosity (mm)
Q
runoff volume (mm)
QR
lateral flow rate (mm d· l )