Understanding the Role of Soils and Management on Crops in the Face of Climate Uncertainty in Zimbabwe: A Sensitivity Analysis

Patricia Masikati,Olivier Crespo,Katrien Descheemaeker

doi:10.1007/978-3-319-92798-5_5

Patricia Masikati, Olivier Crespo + Show 1 more

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https://doi.org/10.1007/978-3-319-92798-5_5

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Abstract

Although climate change is likely to affect a wide variety of sectors in Zimbabwe, the risk to agriculture stands out most since agriculture is the mainstay of the country’s economy. In addition, there is little information available on how to help smallholder farming systems and livelihoods respond to these risks. To determine the effects on crop production of expected changes in precipitation patterns and projected increases in carbon dioxide (CO2) and temperature, we used two process-based crop models—the Decision Support System for Agrotechnology Transfer (DSSAT) model and the Agricultural Production Systems Simulator (APSIM) model. The models were calibrated and validated to assess the effects of single and combined climatic factors on grain and stover yield performance of maize and groundnut, across three soil types. The two models generally agree on the effects that different climatic factors have on both maize and groundnuts, however, the magnitude of the effects varied. For example, reductions on maize grain yields are more pronounced in the APSIM model while the DSSAT model shows more pronounced reduction of maize stover yields. Both models show yield benefits under elevated CO2 concentration for groundnuts negating the effects of increased temperatures when evaluating the combined effects of the climatic factors. However, yield increases for both groundnut grain and stover are more pronounced in the DSSAT model. The key finding is that soils play an important role in determining outputs of crop-climate interactions: they can buffer or aggravate climatic impacts.

Highlights

More than 50% of agricultural land in Africa is degraded and yields of the main staple crops have been at the lower end of the global range for decades (UNCCD 2014; Folberth et al 2013)
Temperature increases in areas such as Zimbabwe where crops are grown near thresholds can be detrimental to rain-fed crop production
In this study, increased temperatures show negative effects on both maize and groundnut yields across soil types with higher yield reductions simulated on the better soils

Summary

Introduction

More than 50% of agricultural land in Africa is degraded and yields of the main staple crops have been at the lower end of the global range for decades (UNCCD 2014; Folberth et al 2013). To meet the demands of a growing population, agricultural land has expanded into forests. This, coupled with unsustainable agricultural practices has led to increased land degradation (Lisk 2009; GGCA 2012). Climate change affects a number of development sectors, the risk to agriculture stands out since the sector represents a significant part of the economies of many African countries (Vermeulen et al 2012). There is no doubt that climate change will amplify drivers of land degradation and pose increased threats on smallholders’ livelihoods of which the majority are women (GGCA 2012; UNCCD 2014)

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