Drought Effects on Global Cereal Production: A Synthesis.

Drought has been a major cause of agricultural disaster, but the impact of factors such crop species, and phenological phase affect the vulnerability of cereal production to drought remains unclear. Using a data synthesis approach, a study was conducted to better characterize the effect of these factors and to provide critical information on minimizing yield loss. We collected data from peer-reviewed publications between 1980 and 2015 which examined cereal yield responses to drought using field experiments. We performed unweighted analysis using the log response ratio to calculate the bootstrapped confidence limits of yield responses and calculated drought sensitivities for several key factors. Our results showed that yield reduction varied with species, with wheat having lower sensitivity to drought compared to maize (yield reduction: 20.6% for wheat vs 39.3% for maize). Drought that occurred during the reproductive phase caused greater yield reduction (30%) than when it occurred during the vegetative phase (20%). While cereal cultivation in the drylands was more prone to yield loss than in the non-dryland regions, no difference was observed among sites of different soil texture. Informed by these results, we discuss low-cost strategies that may be implemented to minimize drought effect on crop yield in the context of a changing climate.