Walloon Agricultural Research Centre Extending Crop Growth Monitoring System (CGMS) for mapping drought stress at regional scale D. Buffet, R. Oger Walloon Agricultural Research Centre Biometry, Data processing and Agrometeorology Unit F. Delongueville, B. Tychon University of Liège, Sciences & Management Dept. Workshop on Climatic Analysis and Mapping for Agriculture June 2005, Bologna, Italy

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – European heat-wave in summer 2003 August 2003 – © CNES The effects of the drought on vegetation in August 2003 is clearly visible at a global scale. Special meteorological weather conditions: Rainfall deficit Higher temperatures But similar or different impacts on various crops ?

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Belgian conditions in 2003 In Belgium, for specific crops, productivities were similar or better in 2003 than 2002 !! Relative difference (%) between productivity in July 2003 with the same period in (Derived from SPOT-VGT images and meteorological data). This can be explained by earlier maturity due to climatic conditions more favorable than last year at the same time. Decade DVS (Phenological Index) Monitoring drought stress spatially and temporally

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – What is drought? Drought is a temporary protracted period of deficient (unusual) in water or moisture availability. 3 different droughts can be considered; Meteorological, Hydrological and Agricultural droughts. (sources FAO & NDMC) Agricultural Drought: Agricultural drought occurs when there is not enough soil moisture to meet the needs of a particular crop at a particular time and in a particular place resulting in extensive damage to crops. It is the impact of meteorological and/or hydrological droughts on crop yields and quality. => Rainfall & Soil Moisture Monitoring Different impacts depending on the crop Different impacts depending on the phenological stage Spatialised Drought Index based on soil moisture deficit ratio and specific to crops and their growth cycle

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – An integrated system : B-CGMS The aim of B-CGMS is to provide the Belgian authorities with reliable, timely and objective estimations of crop yields / productions at regional and national scales. Based on the EU-CGMS (MARS – JRC) B-CGMS = Agrometeorological model + Remote Sensing + Statistics B-CGMS monitors crop development, driven by: 1.meteorological conditions 2.soil characteristics 3.crop parameters 4.satellite data 5 main crops + grasslands monitored at regional & national scales

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Extending B-CGMS for mapping drought stress at regional scale Elementary Mapping Units for Belgium Grid weatherSoil Mapping UnitsAdministrative limits

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Extending B-CGMS for mapping drought stress at regional scale Development and integration of a Drought Stress Indicator using B-CGMS information (input and output data). Meteorological data Availability of spatially accurate soil characteristics Availability of spatially land-use/land-cover 5 main crops + grasslands parameters Spatial information Time series (Monitoring) Drought Stress Index

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Step 1: Relative Soil Moisture Index [RSMI] θ t - θ wp RSMI = θ fc - θ wp Actual soil moisture content [cm3 cm-3] Soil moisture content at wilting point [cm3 cm-3] Soil moisture content at field capacity [cm3 cm-3] Relative Soil Moisture Index [%]

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – B-CGMS Soil Moisture (inputs) θ wp θ fc Volumetric soil water content  as a function of pressure head h  sat = 0,81 + 0,0013*C - 0,283*BD [cm³/cm³]  r = 0, ,005*C + 0,0139*OC [cm³/cm³] ln(  ) = -2, ,025/S - 0,023*C - 0,351*OC - 2,617*BD ln(n) = 0, ,009*S - 0,013*C + 0,00015*S² Vereecken Pedotransfert functions

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Relative Soil Moisture Index [RSMI] θ t - θ wp RSMI = θ fc - θ wp Actual soil moisture content [cm3 cm-3] Relative Soil Moisture Index [%]

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – B-CGMS Soil Moisture (outputs) Crops Weather Soil Temporal θtθt

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Step 2: Soil Moisture Deficit Threshold [T] Forage Maize: T = 0.50 Winter Wheat: T = 0.55 RSMI < T  Drought Stress RSMI >= T  No Drought Stress Soil moisture deficit threshold is crop specific

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Step 3: Crop Sensitive Period [SP] Phenological development stages come from B-CGMS outputs Forage Maize: SP = anthesis +/- 15 days ( 5 weeks) Winter wheat: SP = From Stem elongation to grain filling (  8 weeks) Water stress is crop specific and is function of the crop phenological development stage.

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Step 4: Drought Stress Index [DSI] DSI is defined as the number of days affected by a water stress which occurred during a critical period and for a given crop Drought Stress Index = ∑ ( RSMI < T ) SP

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Step 5: Aggregation into administrative limits Elementary Mapping Units 14 Belgian Agricultural Regions 26 Belgian Agro-statistical Circumscriptions 570 Belgian Municipalities

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – DSI: detect water stress by crops Winter Wheat Forage Maize Drought Stress Index 2003

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – DSI: Spatial comparaison Yield 2003/2002 (%) Drought Stress Index Yield 2003/2002 (%) 2003

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – DSI: Temporal comparaison Forage Maize Drought Stress Index

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – DSI: Water stress monitoring Week 18 Week 19Week 20 Week 21 Week 22Week 23 Forage Maize Drought Stress Index

Walloon Agricultural Research Centre Walloon Agricultural Research Centre (CRA-W) Biometry, Data processing and Agrometeorology Unit – Conclusion Drought Stress Index allows: - Spatial water stress assessment (grid 10x10km or Administrative levels) - Temporal water stress assessment (10-day time step) Useful tool for Administration: - Water stress monitoring to identify calamities areas - Water stress monitoring to identify affected crops - Decision Support Tool for yield damage delineation and evaluation Is based on: - Meteorological parameters (Precipitation deficit assessment) - Soil characteristics (Soil moisture deficit assessment) - Crop specificities (Soil moisture deficit threshold) - Phenological development stage (Crop sensitive period)