ALTERRA

Step wise modelling approach

Climate data long and short term

Soil schematisation

Water fluxes and moisture contents: long and short term

Soil physics

Carbon long term; static experiment

Nitrogen: short term CO2 short term

Soil temperatures

ALTERRA

Climate Long term and short term experiment Data applied:

Rainfall (not corrected) Long term: ET using Dutch equation using Tair,

Rglobal/HrsSun Short term: PenmanMonteith

Result: long term evaporation excess of 57 mm/year Precip-Evap (mm/year)

-400

-300

-200

-100

0

100

200

300

400

ALTERRA

Soil schematization

3 m soil profile 25 soil layers / horizons 45 model compartments water

flow 26 model compartments solute

flow physical dispersion of 2.5-10

cm

ALTERRA

Hydrology – soil temperature

numerical model to solve soil heat equation

example for plot12a/b

ALTERRA

soil physics

Short term experiment

Different relations theta-h

Calibration:1. Default MVG-set2. Hysteresis3. Reduced theta_sat

ALTERRA

Hydrology

soil

moisture

plot12a/b

crop

rotation

ALTERRA

Hydrology

soil

moisture

plot12a/b

crop

rotation

ALTERRA

Model exercise on static experiment

Management: Soil tillage Mineral N fertilizer 2 types of organic

manure

Initial partitioning: 90 % native SOM

(stable) 10% humus/biomass

ALTERRA

Short term conc. NH4-N and NO3-N: black

fallow

ALTERRA

Short term conc. NH4-N and NO3-N: : plot12a/b

cropped

ALTERRA

peculiarities

Meteo: precipitation of short and long term experiment differ (88 mm in 1998)

Soil physical data; same theta gives different heads (what about quality / uncertainty in measurements ?

Nitrate concentration: extremely high in soil solution (625 mg/l NO3-N)

ALTERRA

Conclusions (1)

Long term predictions demand for an appropriate description of slow processes

Partitioning requires long term data sets For long term simulations, generalized data on

land management are sufficient Data of the static experiment are of great value Little influence of soil physical characteristics on

long term carbon dynamics (large on short term N?)

ALTERRA

Partitioning of organic matter pools in the Animo model is important for short term leaching studies: determines mineralization rates Biologigal activity -> denitrification

Animo model could easily be calibrated to data of static experiment

Animo was able to simulate the soil-N contents quite well, but not the soil moisture concentrations

But, it seems there is a discrepancy between soil- nitrogen and soil moisture nitrogen measurements

Conclusions (2)

ALTERRA

On the use of SWAP/ANIMO:

Elaborate more on trace house gas emissions

Short term carbon and nitrogen dynamics requires further analysis, influence of soil physical properties, soil temperature?

Standardize calibration techniques (e.g. GLUE?)

Standardize storage of valuable data sets; include uncertainties

discussion

ALTERRA

Thank you for your attention