Sorghum Yield Response to Changing Climatic Conditions in Semi-Arid Central Tanzania: Evaluating Crop Simulation Model Applicability

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

Growth, Yield and Nutritional Performance of Sweet Sorghum and Legumes in Sole and Intercropping Influenced by Type of Legume, Nitrogen Level and Air Quality

“…It can tolerate adverse climatic conditions like drought [8] and temperature fluctuations [9,10] and can grow on marginal soils [11,12]. The crop is capable of overcoming adverse climatic conditions through flexible growth patterns and sustains grain and biomass production levels [13]. However, in intercropping, the type of legume and nitrogen management influence its growth and yield [14].…”

Who is quitting? An analysis of the dis-adoption of climate smart sorghum varieties in Tanzania

“…In Eastern and Central Africa, sorghum is a major food security crop accounting for 41 per cent of the region's grain production (Msongaleli et al, 2004). Orr et al (2016) report that smallholders in Tanzania grew sorghum primarily as a food crop, responding slowly to changes in relative market prices compared to maize, but reducing the production of sorghum after a year of good rains when they had experienced a bumper harvest of maize.…”

“…Despite its strategic importance, sorghum yields are low, averaging approximately 1000 kg ha -1 which has been broadly attributed to low soil fertility, bird feeding damage, striga, weed infestation, use of cultivars with low yield potentials and other socio-economic factors (Msongaleli et al, 2004). Resulting from increased efforts by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and the National Agricultural Research Institutes, several improved sorghum varieties have been released in the past four decades (Ndjeunga et al, 2015).…”

Evaluation of DSSAT model to predict sorghum yields under Conservation Agriculture in the Pandamatenga vertisols of Northern Botswana

“…The use of models to simulate combinations of tillage systems and crop rotations constitute a powerful tool in assisting decision making to identify efficient system management options, increasing yields and decreasing environmental impacts, in specific-climatic conditions [8]. Msongaleli et al [9] used the DSSAT model to evaluate and simulate sorghum yield under current and future climate. The results showed the crop simulation models' applicability as tools for assessing impacts of climate change on sorghum yields.…”