1. Using APSIM to simulate crop-parasitic weed interactions Plant Production and Agroecology of the Tropics and Subtropics 24.2.2005 – Dr. J. Grenz contact: jangrenz@uni-hohenheim.de

2. Outline The Orobanche problem   The Agricultural Production Systems Simulator   Simulating Host-Parasite Interactions   Applications of APSIM-Parasite   Outlook  

3. O. cumana O. crenata O. minor O. ramosa / O. aegyptiaca Economically important Orobanche species The Orobanche problem - 1

4. Orobanche crenata – crenate broomrape largest Orobanche species common around the Mediterranean mainly attacks Fabaceae, Apiaceae yield losses from 5 to 100% individuals produce numerous highly persistent seeds yet no control method is sufficiently effective and practicable The Orobanche problem - 2

5. Specificity: only attaches to potential hosts Destructivity: grows fully at expense of the host Fecundity: individuals can produce more than 200,000 seeds Longevity: seeds can remain viable in the soil for more than 10 years Mobility: tiny seeds adhere to machinery, seeds, animals, … Aspects of the Orobanche Problem The Orobanche problem - 3

6. Developed at the Agricultural Production Systems Research Unit, Toowoomba (Qld), Australia APSIM simulates: Growth and development of crops, pastures, trees, weeds Key soil processes (water, N, P, carbon, pH) Management options (tillage, sowing, irrigation, fertilisation) Surface residue dynamics Soil erosion Cropping systems Rotations/fallowing/mixtures Short or long term effects The Agricultural Production Systems Simulator APSIM - 1  more information @ www.apsru.gov.au

7. Crops System Control Soil SWIM Manager Report Clock SoilWat SoilN SoilPH SoilP Residue Economics Fertiliz Irrigate Canopy Met Erosion Maize Sorg Legume Wheat New Module Manure Management ENGINEENGINE Parasite APSIM: plug-in-pull-out structure APSIM - 2 Key feature: effects of one crop on another passed on via the soil

8. Quantifying faba bean – O. crenata interactions Experiments in Syria (1993-95)...... and Turkey (2000-02) Host-Parasite Interactions - 1

9. DevelopmentGrowth Faba bean Daily DM Production (PAR, Q, LUE, LAI) DM Partitioning (Roots, Leaves, Stems, Pods) Senescence and Retranslocation Rooting front, RLD, Senescence Emergence Pod setting Seed filling Physiological Maturity Soil Water Drainage, Evaporation, Transpiration, Soil water content Flowering Leaves Branches Structure of the faba bean model Host-Parasite Interactions - 2

10. DevelopmentGrowth O. crenata Assimilate pool Pods StemsRoots Leaves Bud Tubercle Shoot emergence Host maturity Potential growth rate of an O. crenata plant (Temp. sum) Total number of attachments (RLD, O. crenata seed density) DM O. crenata Faba bean emergence Appressorium Structure of the parasite model Host-Parasite Interactions - 3

11. The Cohorting Routine Host-Parasite Interactions - 4

12. Seed production = f (parasite biomass) Seed survival = f (soil moisture) Vertical distribution = f (tillage) Cropping System Crop Host Crop Host Crop Orobanche soil seed bank The seedbank model Host-Parasite Interactions - 5

13. Simulated (curves) and measured (points) leaf area index (LAI), shoot (open circles) and pod biomass (closed circles) of faba bean grown without Orobanche infestation in 1994-95; SD1 and SD2 indicate the first (Nov. 7) and second (Dec. 12) sowing date, respectively. Some calibration results Host-Parasite Interactions - 6

14. Crop phenologyCrop biomass Crop yieldParasite biomass Some evaluation results Host-Parasite Interactions - 7

15. Single-season simulations faba bean cv. ILB 1814 Weather records (1979-2000) from Adana and Tel Hadya 0 resp. 100 O. crenata seeds kg -1 soil (0-15 cm) 7 sowing windows: OktoberJanuary NovemberDecember 22.10.8.11.22.11.8.12.22.12.8.1.22.1. Optimal faba bean sowing windows Model applications - 1

16. Results: Tel Hadya 17.6 °C 339 mm 200 400 600 800 1000 200 400 600 800 1000 00 pod yield (g m -2 ) 22-Oct 8-Nov 22-Nov 8-Dec 22-Dec 22-Jan 8-Jan 22-Oct 8-Nov 22-Nov 8-Dec 22-Dec 22-Jan 8-Jan 10 20 30 40 50 average temperature (°C) total rainfall (mm) 20 40 60 80 100 non-infested100 O. crenata seeds kg -1 soil Model applications - 2

17. Results: Adana 18.8 °C 667 mm 200 400 600 800 1000 200 400 600 800 1000 00 pod yield (g m -2 ) 22-Oct 8-Nov 22-Nov 8-Dec 22-Dec 22-Jan 8-Jan 22-Oct 8-Nov 22-Nov 8-Dec 22-Dec 22-Jan 8-Jan 10 20 30 40 50 average temperature (°C) total rainfall (mm) 20 40 60 80 100 non-infested100 O. crenata seeds kg -1 soil Model applications - 3

18. Multi-Season Simulations 200 400 600 800 1000 0 Tel HadyaAdana yield of non-infested crop yield of infested crop seed bank (0-15 cm) 0 pod yield (g m -2 ) 200 400 600 800 1000 0 1 2 3 4 0 1 2 3 4 seed bank (million seeds m -2 ) 5-course rotation unfeasible at both locations more rainfall  more biomass  more parasite seeds high soil moisture level  rapid seed decay 1980198519901995200019801985199019952000 Model applications - 4

19. Evaluation of trap cropping, soil solarisation, biological control and further measures Data collection for more mechanistic modeling of seed bank decay Addition of a spatial component (cellular automaton) Application of the approach to further host-parasite associations... Your suggestions ? Prospects for model improvement

20. On the APSIM approach and framework: -McCown, Hammer, Hargreaves, Holzworth, Freebairn (1996). Agric. Syst. 50, 255-271. -Keating, Carberry, Hammer et al. (2003). Eur. J. Agron. 18, 267-288. -Wang, Robertson, Hammer et al. (2003). Eur. J. Agron. 18, 121-140. On Host-Parasite Simulation: -Manschadi, Sauerborn, Stützel (2001). Weed Res. 41, 311-324. -Manschadi, Wang, Robertson, Meinke, Sauerborn (2003). www.regional.org.au/au/asa/2003/c/18/manschadi.htm -Manschadi, Hargreaves, Grenz, DeVoil, Meinke (2004). www.regional.org.au/cs/2004/poster/ 2/8/1218_manschadi.htm -Grenz, Manschadi, DeVoil, Meinke, Sauerborn (2004). www.regional.org.au/cs/2004/poster/2/4/1/1236_grenz.htm Selected references