TITLE:
Sorghum Yield Response to Changing Climatic Conditions in Semi-Arid Central Tanzania: Evaluating Crop Simulation Model Applicability
AUTHORS:
Barnabas Msongaleli, Filbert Rwehumbiza, Siza D. Tumbo, Nganga Kihupi
KEYWORDS:
Yield Prediction, Climate Change, Adaptation, Model Evaluation
JOURNAL NAME:
Agricultural Sciences,
Vol.5 No.10,
August
7,
2014
ABSTRACT:
Decision Support System for Agrotechnology Transfer (DSSAT) and
Agricultural Production Systems SIMulator (APSIM) were calibrated and
evaluated to simulate sorghum (Sorghum
Bicolor L. Moench) var. Tegemeo under current and future climate in central Tanzania. Simulations for both
current and future periods were run assuming present technology, current
varieties and current agronomy packages to investigate rain-fed sorghum yield
response. Simulations by both crop models using downscaled weather data from
eight General Circulation Models (GCMs) under the Coupled Model Intercomparison
Project phase 5 (CMIP5) and Representative Concentration Pathway (RCP 4.5) by
mid-century show a mixture of increase and decrease in median sorghum yields.
Four GCMs project yields to increase by 5% - 23.0% and one GCM show a decrease
by 2% - 9%. Model simulations under the remaining three GCMs give contrasting
results of increase and decrease. Adjustment of crop duration to mimic the
choice of growing local cultivars versus improved cultivars
seems a feasible option under future climate scenarios. Our simulation results
show that current open-pollinated sorghum cultivars would be resilient to
projected changes in climate by 2050s but things seem better with long duration
cultivars. We conclude that crop simulation models show their applicability as
tools for assessing possible impacts of climate change on sorghum due to
agreement in the direction of crop yield predictions in five out of eight
selected GCMs under projected climate scenarios. The findings provide useful
guidance and motivation to government authorities and development agencies
dealing with food security issues to prioritize adaptations policies geared to
ensuring increased and sustained sorghum productivity in Tanzania and
elsewhere.