Jäckel, G.

Kunstmann, H.

Laux, P.

Munang, T.R.

Waongo, M.

English

Munang, T. R.

KITopen

KIT – Universität des Landes Baden-Württemberg undnationales Forschungszentrum in der Helmholtz-GemeinschaftIINSTITUTE OF METEOROLOGY AND CLIMATE RESEARCH, GARMISCH-PARTENKIRCHEN, GERMANYwww.kit.eduA new method to improve attainable crop yield by planting date adaptationsA case study for CameroonInstitute of Meteorology and Climate Research IMK-IFU 2 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)20.02.2012P. Laux1, M. Waongo1,2, H. Kunstmann1,2, G. Jäckel1, T. R. Munang31 Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research (IMK-IFU), Germany2 University of Augsburg, Regional Climate and Hydrology, Germany3 Climate Change Adaptation Unit, Division of Environmental Policy Implementation (DEPI), United Nations Environment Programme (UNEP), Nairobi, KenyaInstitute of Meteorology and Climate Research IMK-IFU 3 Rainfall = major limiting factor for agriculture in sub-Saharan Africa Economies of SSA highly exposed to rainfall variability Agriculture accounts for 35% of the GDP, employs 70% of population ~ 90% of cropland managed under rainfed conditions High rainfall variability on intra-annual, inter-annual and decadal scales Crucial problem for rainfed agriculture: Decision about the optimal planting date for current season Planting as early as possible to avoid wasting of valuable growth time Planting too early may lead to crop failures and high economic losses CC will aggravate rainfall variability and water scarcity in 21. CenturyMotivation:20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 4“Challenge” for agricultural management underrainfed conditions in sub-Saharan AfricaScientifically sound information for decision support under present and future climate conditions and weak infrastructure20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 5„Challenges“ … more specifically1. Development of agriculturally relevant ORS approach  optimal planting rules accounting for intra-seasonal variability of rainfall2. Estimate the impact of planting date on “attainable” crop yield under current and future climate conditionsPotential Solutions1. Development  “optimal planting date following crop modeling system”2. Application for past and future and comparison to traditional planting dates20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 6“Optimal planting date following crop modeling system”CropSystManagement• Planting date• Ploughing• Fertilization• etc.Weather• Temperature• Precipitation• Radiation• (CO2) • etc.Crop Yield (1979-2003)AlgorithmOnset Rainy SeasonPlanting date for each yearSoil properties20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 7CropSyst model (Stöckle et al., 2003) Multi-year, multi-crop process-based simulation model  to study the effect of climate, soil, and management on productivity and environment of cropping systems Calibration: Parameterization of crop-specific values (e.g. phenology) by IRA (Cameroon) and literature review Validation Difference modeled and observed yields acceptable (< 10%) Represents inter-annual and spatial variability of observed crop yield20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 8Algorithm: Onset of the Rainy Season (ORS) Literature review: … many rainfall-based (threshold) approaches Stern et al., 1981: ORS as first DOY with rainfall > 20mm within 2 consecutive days) Sivakumar, 1988: Rainfall within 3 consecutive days ≥ 20 mm, no dry spell of 7 days within next 30 days … Problem: Threshold-based approaches too strict (binary logic) Solution: Fuzzy logic-based ORS approach  Applied for Volta Basin of West Africa (Laux et al., 2008, 2009)  3 membership functions (criterions)20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 9#1: Rainfall amount criterion Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)20.02.2012 µ1: 2 parameters a1, a2 Sufficient water at planting stageµ1Rainfall amount within 5-day-period [mm]a1a2Institute of Meteorology and Climate Research IMK-IFU 10µ2b1b2Number of wet days within 5-day-period [days] µ2: 2 parameters b1, b2 exclude single heavy showers as ORS #2: Multiple rainy days criterion 20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 11 µ3: 2 parameters c1, c2 exclude total crop failureNumber of consecutive days after ORS, in which no dry spell > 6 days occurs [days]  c1c2µ3#3: False start criterion20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 12Combining #1, #2, and #3 for planting decision Total membership grade:µTOT = µ1 · µ2 · µ3IF µTOT  > threshold k [0,...,1], THEN Onset Rainy Season (planting) ORS approach with 7 parameters: k, a1, a2, b1, b2, c1, c2 Parameters depend on region (weather, soil) and plant physiological aspects  Optimization for each crop and station of interest20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 13Parameter optimisation algorithm20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 14Case study: CameroonGarouaNgaoundéréBatouriYaoundéBamenda1090 mm/a1514 mm/a2380 mm/a1500 mm/a1600 mm/aMarch 15May 15Traditional planting dates:20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 15GarouaYaoundéBatouriNgaoundereBamendaResults optimisation: Yaoundé (maize)→ Mean attainable crop yield (1979-2003) increases per iteration→ Distribution narrows (more stable yields)20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 16Parameter space after 10 iterations20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 17ORS algorithm vs. traditional planting calendarProposed new method for planting dates would have allowed for:→ Increase in mean attainable crop yield: Yaoundé 15%, Garoua 50%→ Crop yield increases in anomalous dry yearsGarouaYaoundéBatouriNgaoundereBamenda20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 18Impact of climate change on crop productivity1. Daily climate scenarios for 2020s and 2080s using ClimGen based on HadCM3 and GISS, and A2 and B2 scenario (8 scenarios for each station) Tmin, Tmax, Solar radiation Precipitation2. Atmospheric CO2 conditions for baseline period 1961-1990, 2020s, and 2080s3. Crop yield simulations using future climate scenarios under baseline/future atmospheric CO2 conditions4.  Crop yield simulations with/without adaptations of the planting date20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 19Local climate scenariosDr. Patrick Laux - PICREVAT workshop Embu (Kenya)20.02.2012Institute of Meteorology and Climate Research IMK-IFU 20Impact of planting date adaptations at GarouaCompared to traditional planting dates: → Increase of groundnut (maize) yields→ But: widened distribution for future crop yields: increase in variability!Distribution of mean crop yield at Garoua (2020s)20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 21Summary Optimal planting date following crop modeling system  Optimal planting rules (crop + location) Significant increase of mean attainable crop yield,      particularly at drier northernmost stations (Garoua, Batouri) Not working for “wet conditions” (Bamenda)  Impact CC on future crop yield estimations Groundnut yields are expected to increase in the 2020s and 2080s, Maize yields are expected to increase (decrease) in the 2020s (2080s) Using ORS approach reduces negative impacts of CC on maize yield (2080s) at northernmost stations20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 22ReferencesLaux, P., Jäckel, G., Munang, R. - T., Kunstmann, H. (2010): Impacts of climate change on agricultural productivity under rainfed conditions in Cameroon - A method to improve attainable crop yields by planting date adaptations, Agricultural and Forest Meteorology 150, pp. 1258-1271, DOI: 10.1016/j.agrformet.2010.05.008.Laux, P., Wagner, S., Wagner, A., Bárdossy, A., Jacobeit, J., Kunstmann, H. (2009) Modelling Daily Precipitation Features in the Volta Basin of West Africa, International Journal of Climatology, Volume 29, Issue 7, pp. 937-954, DOI: 10.1002/joc.1852. Laux P., Kunstmann, H., Bárdossy, A. (2008) Predicting the Regional Onset of the Rainy Season in West Africa, International Journal of Climatology, Volume 20, Issue 3, pp. 329-342, DOI: 10.1002/joc.1542. Laux, P., Jäckel, G., Tingem, M., Kunstmann, H. (2009): Onset of the rainy season and crop yield in Sub Saharan Africa - Tools and perspectives for Cameroon. Thoms, M. Et al. (eds): Ecohydrology of Surface and Groundwater Dependent Systems: Concepts, Methods and Recent Developments, Hyderabad, India, September 6-12, 2009. IAHS Publication 328, 191-201. Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)20.02.2012Institute of Meteorology and Climate Research IMK-IFU 23Further Improvements  Improvement of approach → PhD thesis M. Waongo „Coupling“ with regional crop model (e.g. GLAM) Objective function Sampling e.g. Latin Hypercube instead of MC Local climate scenarios Sophisticated bias correction methods (e.g. Copula-based approach, Local Scaling, QQ-transformation) SDS and/or DDS methods Evaluation of approach for West Africa (WASCAL) and East Africa Field studies required to confirm resultsDr. Patrick Laux - PICREVAT workshop Embu (Kenya)20.02.2012Institute of Meteorology and Climate Research IMK-IFU 24Thank you for your attention!20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 25Impact planting dates on future crop yield GISS and HadCM3 A-OGCM, A2 und B2 scenario ClimGen for statistical downscaling of GCM output20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 26 20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 27Direct CO2 effects + ΔP & ΔT + planting date adaptationsCompared to baseline 1961-1990: → Increase of groundnut yields for the 2020s and 2080s→ Increase (decrease) of maize yields for the 2020s (2080s)  → Aggravation of growing conditions for Bamenda20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 28Calibration/Validation CropSyst Parametrisation crop-specific values (maize, groundnut) Publications (e.g. Tingem et al., 2008) CropSyst user manual Phenological parametrisation (e.g. GDD) Institute of Agricultural Research (IRA) Cameroon Validation: 5-year-period of observed yields:  Difference between modeled and observed yields acceptable Interannual and spatial variability of crop yields Bild Validation20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 29Initialization parameter domain (7 parameters)Randomisation (500 realisations) of  the 7 parametersCalculation of the ORS dates (1979-2003) using ORS approachSimulation Mean Crop Yield MCY (500 realisations) using CropSyst and ORS dates IterationsParameter domain of best 5% simulationsOptimal parameter domain for definition ORSΔ (MCY) < thresholdΔ (MCY) > thresholdORS parameter optimisation20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 30 20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 31 20.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)Institute of Meteorology and Climate Research IMK-IFU 32Cameroon: Factors affecting rainfall variabilityHigh spatial and temporal rainfall variability Climate: semi-humid (South) to semi-arid (North) Intertropical Convergence Zone (ITCZ) South: bimodal (april/may & september/october)North: unimodal (august/september) TopographyGarouaYaoundéBatouriBamendaNgaoundéréElevation (m.a.s.l.)-26 - 250 251 - 500501 - 750751 - 1.0001.001 - 1.2501.251 - 1.5001.501 - 1.7501.751 - 2.0002.001 - 3.0003.001 - 4.02420.02.2012 Dr. Patrick Laux - PICREVAT workshop Embu (Kenya)

A new method to improve attainable crop yield by planting date adaptations

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A new method to improve attainable crop yield by planting date adaptations

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