AquaCrop A new model for crop prediction under water deficit conditions - Calibration for potato -

Transcription

1 AquaCrop A new model for crop prediction under water deficit conditions - Calibration for potato - Gabriella IZZI gabriella.izzi@fao.org Centro Internacional de la Papa (CIP) La Molina, Lima, Peru 22 September, 2008

2 Objectives General framework Description of AquaCrop Main issues related to AquaCrop calibration for potato AquaCrop performances Discussion, feed-backs, & contacts

3 Background Revision of the 1979 FAO I & D Paper no.33, Yield Response to Water Ya ETa 1 - = Ky 1 - Ym ETc Consultative process Separation herbaceous-crops and trees: AquaCrop & Guidelines

4 Why another model? total Uncertainty parameters structure Complexity

5 AquaCrop main characteristics AquaCrop differs from other models for its relatively small number of parameters AquaCrop is explicit and mostly intuitive, and maintains an optimum balance between simplicity, accuracy and robustness AquaCrop is aimed at practical end-users: farmers and irrigation associations, extension services, governmental agencies, NGOs, planners, economists, as well as researchers and students. AquaCrop as unique crop response to water model with crop-specific parameters

6 AquaCrop Network & CGIAR

7 Evolution from Paper 33 Water-driven model AquaCrop { HI BIOMASS WP daily time-steps Canopy Transpiration E Paper 33 YIELD Ky Crop Evapotranspiration long-term sums

8 AquaCrop Conceptual Framework Atmosphere Crop Soil Management

9 AquaCrop Conceptual Framework Atmosphere CLIMATE Rain R S, T, RH, u ET o T ( o C) CO 2

10 Data needed for calibration Atmosphere Rainfall ETo Tmin & Tmax

11 AquaCrop Conceptual Framework Crop Phenology Leaf expansion g s Canopy Cover Senescence Rooting depth

12 AquaCrop Conceptual Framework Crop canopy cover CCo CGC CCx CDC Canopy Cover (CC) follows the exponential growth during the first half of the full development (Eq. 1) and an exponential decay during the second half of the full development (Eq. 2) time to full canopy start of canopy senescence time to harvest time CC CC e CGC t = (1) o CC x x o CGC t = CC (CC CC ) e (2)

13 Data needed for calibration Crop Density In-season CC Phenology

14 AquaCrop Conceptual Framework Crop T ( o C) ET o E s T a WP Phenology Leaf expansion g s Canopy Cover Senescence Rooting depth Biomass

15 AquaCrop Conceptual Framework Crop WP = Biomass T C (g m -2 mm -1 ) WP * = Biomass T C ET O CO 2 (2000) (g m -2 ) Biomass (kg m -2 ) Sorghum Sunflower Chickpea Wheat Biomass (kg m -2 ) Sorghum Sunflower Chickpea Wheat Σ ETc TC (mm x 1000) Σ(ETc/ETo) ( TC / O )

16 Data needed for calibration Crop In-season dry biomass

17 AquaCrop Conceptual Framework Crop T ( o C) ET o E s T a WP Phenology Leaf expansion g s Canopy Cover Senescence Biomass HI Yield Rooting depth

18 Data needed for calibration Crop In-season yield

19 AquaCrop conceptual framework Crop Water stress coefficients

20 AquaCrop conceptual framework Crop Water stress coefficients

21 Data needed for calibration Crop Different water regimes

22 AquaCrop Conceptual Framework Soil Rain Irrig. Runoff E s Ks Infiltration Soil water (& salt) balance Redistribution T a Texture 1 Texture 2 Texture Runoff K sat FC PWP deep percolation

23 Data needed for calibration Soil Soil layers FC, PWP, Ksat

24 AquaCrop Conceptual Framework Management Water Management Rainfed Irrigation User defined schedule (timing and depth) Model-generated schedule (fixed interval; fixed depth; % of RAW) Irrigation method (drip; sprinkler; surface» basin; border; furrow) Field Management Fertility level (non-limiting; high; moderate; poor) Field-surface practices (mulching; soil bunds)

25 Data needed for calibration Management Irrigation date Irrigation depth

26 Data needed for calibration Management Fertility level

27 AquaCrop performances

28 Maize Texas Spain Quzhou California Florida

29 Maize California Treatments: Full Irrigation (I) Rainfed (NI) Irrig. day 55 onward (I55) Biomass Yield Measured Simulated Measured Simulated I55 (IRR NI I (Full (No on IRR) Day55) treatment Ground Ground Cover Cover I55 NI I treatment biomass GC (%) Calc Calc Calc GC GC GC 20 CC CC CC cum DM (g/m2) DM Biomass DM Biomass DM Biomass DAP DAP

30 Cotton Texas Spain Greece Syria Turkey

31 Cotton Spain Treatments: Full Irrigation Deficit Irrigation 14 Sim ulated (t ha -1 ) Yield Biomass 1: Observed (t ha -1 )

32 Cotton Syria Treatments: Full Irrigation Deficit Irrigation

33 Wheat Texas Kansas Sardinia Luancheng Quzhou Fengqui

34 Wheat China Treatments: Full Irr Full Irr. 100 Yield Measured Simulated China Quzhou Wheat China Quzhou Wheat Min Min and and Max Max Temperature Temperature (oc) (oc) China Quzhou Wheat DAP Canopy Cover (%) Biomass (t/ha) China Quzhou Wheat China Quzhou Wheat DAP DAP

35 Bolivia Quinoa

36 Quinoa Bolivia Treatments: Full Irrigation Deficit Irrigation

37 Conclusions AquaCrop shows first encouraging results, under full, deficit and rainfed conditions AquaCrop needs to be calibrated for potato AquaCrop calibration and validation need solid datasets, under a variety of agro-climatic, water and fertilization conditions

38 Thank You