“Our results show that an eco-intensification approach can provide some resilience for maize cultivation in certain parts of sub-Saharan Africa while conventional intensification appears more suitable in others,” Christian Folberth of the Swiss Federal Institute of Aquatic Science and Technology and IIASA, Austria told environmentalresearchweb. “Very high increases in temperature, however, can only be faced by improvements in choice of crop and cultivar as temperature stress can hardly be influenced by crop management directly.”

Folberth and colleagues used a GIS-based EPIC (Environmental Productivity Integrated Climate) model to analyse the effect of climate change on maize yield under different crop management regimes – conventional intensification by adding mineral fertilizer, rotation with cowpea with or without the addition of mineral fertilizer, and rotation with Sesbania sesban with or without the addition of mineral fertilizer. They simulated maize yield for 1996 to 2090 using projections from three different climate models for a low-emissions and a high-emissions scenario.

“Assessments of climate-change impacts on agricultural production have previously mostly been carried out assuming business-as-usual crop management for the coming decades,” said Folberth. “This is, however, quite unlikely given the present economic growth in many parts of sub-Saharan Africa.”

Sub-Saharan Africa has some of the lowest yields for maize worldwide. Until the 2040s rotating maize crops with Sesbania sesban will help boost yields, the team found. The tree can increase nitrogen supply, help water infiltration and boost soil’s water-holding capacity. Towards the end of the century, however, it looks like yields will decrease under all three management regimes if temperatures rise too high.

“Farmers, policymakers, NGOs and other stakeholders of the agricultural sector should look at different options for climate change adaptation,” said Folberth. “While there has been a focus on the extension of irrigated areas, improved cultivars, and changes in sowing dates in agricultural modeling of climate change impacts, our results show that soil and fallow management can also have significant influence on climate change impacts.”

Now Folberth and colleagues plan to investigate processes in the model that make the crop more resilient or more vulnerable to climate change under different crop management strategies.

The team reported the study in Environmental Research Letters (ERL).

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