DaisyModellingUk1

Daisy: 

Daisy Basic modelling concepts Søren Hansen The Royal Veterinary and Agricultural University Department of Agricultural Sciences Laboratory for Agrohydrology and Bioclimatology Højbakkegård Allé 9 Dk-2630 Taastrup Denmark

Braunschweig workshop Validation of agro-ecosystem modelsA comparison of results of different models applied to the same datasets: 

Braunschweig workshop Validation of agro-ecosystem models A comparison of results of different models applied to the same datasets The simulation results obtained from 19 participants of the workshop “Validation of Agro-ecosystem Models” were compared and discussed. Although all models were applied to the same data set, the results differ significantly. From the results it can be concluded that the experience of a scientist applying a model is as important as the difference between various model approaches. Only one model simulated all main processes like water dynamics, plant growth and nitrogen dynamics with the same quality, the others are able to reproduce the measured dynamic only in part. Diekkrüger et al., Ecological Modelling 1995.

Slide3: 

Macropores Pesticide Macropores Nitrate Macropores Ammonium Macropores Organic Matter Macropores Heat Soil matrix Macropores Water Soil Uptake Turnover Sorption Transport Phase change Bioclimate SVAT Light distribution Interception Snow accumulation Vegetation Growth Photosynthesis Respiration Uptake DAISY Simulation Model Numeric layer Soil Data Vegetation Data Weather Data Management Data

Weather Data – Daily Values: 

Weather Data – Daily Values Minimum Dataset (Makkink equation) Global radiation Air temperature Precipitation Additional data Reference Evapotranspiration Full Dataset (FAO-Penman-Montheith) Global radiation Air temperature Humidity Wind speed Precipitation

Weather Data – Hourly Values: 

Weather Data – Hourly Values Full Dataset (Sparse Canopy – Shuttleworth & Wallace) Global radiation Air temperature Humidity Wind speed Precipitation Additional data Ref. Evap.

Slide6: 

Precipitation & Irrigation Snowpack Intercepted water Snow fall Rain fall Ponded water Percolation Throughfall Infiltration Soil Evaporation Transpiration Evaporation Evaporation Evaporation Percolation Soil water Capillary rise

Potential Evapotranspiration: 

Potential Evapotranspiration crop factor and reference evapotranspiration crop factor as function of time (Feddes, 1987) crop factor as function of development state (Allen et al.,1998)

Crop factor, kc (Feddes, 1987): 

Crop factor, kc (Feddes, 1987)   † Short grass 5-15 cm (Grass 15-25 cm, kc=1.1)

Slide9: 

Snowpack Solid water in snowpack Liquid water in snowpack Melting Freezing Precipitation Percolation Rain fall Snow fall Sublimation Evaporation

Soil Water Processes: 

Soil Water Processes Soil Water: θ, h, K Soil Water: θ, h, K Soil Water: θ, h, K

Daisy Carbon Flow Model: 

Harvest Photosynthesis Plant Respiration Yield Soil Carbon Residue Incorporation Rhizodeposition Organic Fertilizer Carbon Soil Microbial Respiration Crop Carbon Soil Carbon Daisy Carbon Flow Model

Slide13: 

AOM AOM SMB SOM N N C Recalcitrant C C C N N C-AOM1 C-SOM1 C-SOM2 N N NH4, NO3 C-AOM2 CO2 C-SMB2 Structural Metabolic C-SMB1

Nitrogen Processes: 

Nitrogen Processes NH4+ NO3- Nitrification Org-N Plant-N Uptake

Nitrogen Processesin a soil layer: 

Nitrogen Processes in a soil layer NH4+ NO3- Nitrification Org-N Root-N Uptake Immobil. NH4+ Transport NO3- Transport Net- Mineralization Uptake NO3- Transport Denitrification Rhizodeposition NH4+ Transport

Slide16: 

Daisy Crop Model Many parametres are a function of the development stage (DS)

Development stage (DS): 

Development stage (DS) DS phases Emergence phase (sowing/planting to emergence) DS in the interval –1 to 0 Vegetative phase DS in the interval 0 to 1 Reproductive phase DS in the interval 1 to 2

Development stage (DS)Emergence phase: 

Development stage (DS) Emergence phase Temperature sum model Parameters Soil temperature threshold Soil temperature sum at emergence

Development stage (DS)Vegetative phase: 

Development stage (DS) Vegetative phase Temperature sum model Default model Parameters Development rate [day-1] Temperature effect Photoperiod effect

Development stage (DS)Reproductive phase: 

Development stage (DS) Reproductive phase Temperature sum model Default model Parameters Development rate [day-1] Temperature effect

Crop Photosynthesis: 

Crop Photosynthesis Light Distribution Leaf area distribution of individual crops Composite canopy Distribution of absorbed PAR Beers’ law Partitioning of distributed absorbed PAR among crops

Crop Photosynthesis: 

Crop Photosynthesis Light response curve Intensity of absorbed PAR, Sa Temperature effect Senescence Water and Nitrogen Stress

Crop Photosynthesis: 

Crop Photosynthesis Canopy photosynthesis Integration over the canopy Where L is the LAI accumulated from the top of the canopy

Maintenance Respiration: 

Maintenance Respiration Maintenance Respiration Root Leaf Stem Storage organ (grain) Total maintenance Respiration

Partitioning: 

Partitioning Allocation of assimilates to: Root Leaf Stem Storage Organs (Grain) Grain Root Shoot Leaf Stem

Growth Respiration: 

Growth Respiration Conversion Efficiency Growth respiration (CO2-evolution) Simple biochemical analysis (Vertregt & Penning de Vries, 1987) Leaf Stem

LAI development: 

LAI development Leaf weight Specific leaf area LAI-modifier (function of development stage)

Crop Nitrogen Relations: 

Crop Nitrogen Relations Maximum N content (uptake) Critical N content (production) Minimum N content, Non functional limit (production)