Crop yield sensitivity of global major agricultural countries to droughts and the projected changes in the future

Crop yield sensitivity of global major agricultural countries to droughts and the projected changes in the future

Guoyong Leng and Jim Hall

Environmental Change Institute, University of Oxford

agriculture 593087

Livestock production can have many environmental impacts, one of which is the use of water. When livestock are fed on crops that have been cultivated with irrigation, the water footprint can be staggeringly high. The UN Food and Agriculture Organization estimates about 69% of all water withdrawals worldwide are used for agriculture, and on average 37% of the cereals produced in the world are used for animal feed. However, the environmental impact of water withdrawals for feed crops depends on where and when the water is used. Water withdrawals from places where water use is already unsustainable can be especially harmful, in particular at times of extreme water scarcity i.e. during droughts. Our analysis on the impacts of livestock production on the aquatic environment has begun with in-depth analysis of the places and times when water resources for agriculture are most scarce. This paper, published in Science of the Total Environment, sets out our methodology and results for identifying where drought impacts on agriculture are most critical. It paves the way for the next step, which will be to identify hotspots where production of feed crops is most harmful for scarce water resources.


Understanding the potential drought impacts on agricultural production is critical for ensuring global food security. Instead of providing a deterministic estimate, this study investigates the likelihood of yield loss of wheat, maize, rice and soybeans in response to droughts of various intensities in the 10 largest producing countries. We use crop-country specific standardized precipitation index (SPI) and census yield data for 1961–2016 to build a probabilistic modeling framework for estimating yield loss risk under a moderate (−1.2 < SPI < −0.8), severe (−1.5 < SPI < −1.3), extreme (−1.9 < SPI < −1.6) and exceptional (SPI < −2.0) drought. Results show that there is >80% probability that wheat production will fall below its long-term average when experiencing an exceptional drought, especially in USA and Canada. As for maize, India shows the highest risk of yield reduction under droughts, while rice is the crop that is most vulnerable to droughts in Vietnam and Thailand. Risk of drought-driven soybean yield loss is the highest in USA, Russian and India.

Yield loss risk tends to grow faster when experiencing a shift in drought severity from moderate to severe than that from extreme to the exceptional category, demonstrating the non-linear response of yield to the increase in drought severity. Sensitivity analysis shows that temperature plays an important role in determining drought impacts, through reducing or amplifying drought-driven yield loss risk. Compared to present conditions, an ensemble of 11 crop models simulated an increase in yield loss risk by 9%–12%, 5.6%–6.3%, 18.1%–19.4% and 15.1%–16.1 for wheat, maize, rice and soybeans by the end of 21st century, respectively, without considering the benefits of CO2 fertilization and adaptations. This study highlights the non-linear response of yield loss risk to the increase in drought severity. This implies that adaptations should be more targeted, considering not only the crop type and region but also the specific drought severity of interest.


Publication details

Leng, G., Hall, J. 2019. Crop yield sensitivity of global major agricultural countries to droughts and the projected changes in the future,
Science of The Total Environment 654(