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Spatially explicit modeling of impacts of adaptive agronomic measures on crop water productivity and yields in the context of water scarcity and climate change in Sub-Saharan Africa

English title Spatially explicit modeling of impacts of adaptive agronomic measures on crop water productivity and yield in the context of water scarcity and climate change in Sub-Saharan Africa
Applicant Yang Hong
Number 138608
Funding scheme Interdisciplinary projects
Research institution EAWAG Systems Analysis, Integrated Ass. & modeling
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Social geography and ecology
Start/End 01.02.2012 - 31.01.2013
Approved amount 57'008.00
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All Disciplines (3)

Discipline
Social geography and ecology
Economics
Meteorology

Keywords (3)

crop model; climate change; adaptation

Lay Summary (English)

Lead
Lay summary

In the realm of climate change studies, assessing impacts of climate change on food production and adaptation measures has received much attention in recent years. Bio-physical crop growth models combined with GIS techniques provide useful tools for such studies because of their ability to simulate impacts of changes in bio-physical conditions on crop production with special details. The existing large-scale bio-physical model applications, however, have generally used the default parameters calibrated in the regions where the models were initially developed, which often do not reflect the local conditions where the models are applied. This can lead to substantial deviations of the simulated results from the statistical and empirically measured data in individual locations, particularly for the low yield areas. This project aims to fill some of the research gaps in the large-scale modeling of water-food relations in the context of climate change. Built upon the adjusted large-scale crop model GIS-EPIC (GEPIC) and the data collected during the preceding projects, the major objective of this project is to assess the potentials of different agronomic practices to improve crop yields and water productivity in Sub-Saharan Africa under various climate change projections. The balance between potential food production and future demand at the sub-country level will be used to identify the hotspots of high vulnerability and food insecurity.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
School of Bioresources Engineering and Environmental Hydrology, University of KwaZulu-Natal South Africa (Africa)
- in-depth/constructive exchanges on approaches, methods or results
Stokeholm Environmental Institute Sweden (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Institute of Crop Science and Resource Conservation, University of Bonn Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved


Associated projects

Number Title Start Funding scheme
103600 Water Scarcity - Its Measurement and Implications for Virtual Water Import 01.04.2004 Project funding (Div. I-III)
122479 Global agricultural green and blue water consumptive uses and virtual water flows in the context of water scarcity and climate change 01.02.2009 Interdisciplinary projects
146430 Application of a Spatially Explicit Bio-physical Crop Model to Assess Drought Impact on Crop Yield and Crop-Drought Vulnerability in Sub-Saharan Africa 01.12.2013 Interdisciplinary projects

Abstract

In today’s world, nearly one sixth of the global population is enduring water scarcity and food insecurity. The problem is particularly acute in Sub-Saharan Africa. Likely negative impacts of climate change are compounding the situation. To meet the challenge, improving crop water productivity and yield with locally suitable and climate change adapted measures is of primary importance. The proposed follow-up project is a continuation of the preceding project ‘global agricultural green and blue water consumptive uses and virtual water flows in the context of water scarcity and climate change’ (SNF K-21K0_122479). Three tasks carried out in the preceding project are: 1) Assessment of consumptive green and blue water uses and yields of major staple food crops at the global level under future climate change; 2) Adaptation of a large-scale GIS-based EPIC model (GEPIC) to crop growth parameters adjusted to local conditions, and 3) Analysis of impacts of improved agronomic measures/practices on crop water productivity and yields of major staple food crops in smallholder agriculture in Sub-Saharan Africa. The proposed follow-up project fulfills task 4) Assessment of potentials of improved agronomic practices under the projected climate change and the implications for food security in Sub-Saharan Africa. The funding for the follow-up project will support the Ph.D student carrying out the four tasks to complete his Ph.D. In the realm of climate change studies, assessing impacts of climate change on food production and adaptation measures has received much attention in recent years. Bio-physical crop growth models combined with GIS techniques provide useful tools for such studies because of their ability to simulate impacts of changes in bio-physical conditions on crop production with special details. The existing large-scale bio-physical model applications, however, have generally used the default parameters calibrated in the regions where the models were initially developed, which often do not reflect the local conditions where the models are applied. The analysis conducted in the preceding project using the GEPIC model reveals that this approach can lead to substantial deviations of the simulated results from the statistical and empirically measured data in individual locations, particularly for the low yield areas, although at the country and continental level the aggregated simulation results may be compared well with the statistical data due to the offset of under- and overestimations in individual locations. Another problem of this approach which is more relevant to the efforts to improve agricultural production is the possible misidentification of major stress factors to crop growth in the areas where the model is applied. For example, in many areas of Sub-Saharan Africa, applying the default GEPIC parameters in the simulation suggests low soil moisture as the major stress to crop growth. However, after the adjustment of parameters to the local conditions, the simulation shows that nutrient stress is the main constraint. Given this situation, it can be expected that using large-scale models without proper adjustment of parameters to local conditions in simulating the impacts of climate change on various aspects of crop growth will yield unreliable or even wrong results. Actions and measures aiming at adapting and mitigating impacts of climate change could be misled by these results. This follow-up project will fill some of the research gaps in the large-scale modeling of water-food relations in the context of climate change. Built upon the adjusted large-scale model GEPIC and the data collected during the preceding project(s), the major objective of the proposed follow-up project is to assess the potentials of different agronomic practices to improve crop yields and water productivity in Sub-Saharan Africa under various climate change projections. The balance between potential food production and future demand at the sub-country level will be used to identify the hotspots of high vulnerability and food insecurity.
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