Closing water productivity gaps to achieve food and water security for a global maize supply

Huifang Zheng,Yulong Yin,Hao Ying,Zhenling Cui,Qianqian Bian,Qinghua Yang

doi:10.1038/s41598-018-32964-4

Huifang Zheng, Yulong Yin + Show 4 more

Open Access

https://doi.org/10.1038/s41598-018-32964-4

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Abstract

To achieve food and water security, it is as important to close the water productivity (WP) gap (which was defined as the difference between the maximum attainable WP and the currently achieved WP at the field scale) as it is to close yield gaps. However, few studies have provided quantitative estimates of existing WP gaps and constraining factors for global maize production. Using a meta-analysis of 473 published studies covering 31 countries and 5,553 observations (932 site-years), we found the global average WP value for irrigated maize was 18.6 kg ha−1 mm−1. These WPs varied by factors such as seasonal precipitation, irrigation regimes, soil organic matter and soil pH. In current production systems, there exists a huge scope for improvement in maize WP, but the reported field experiments achieved only 20–46% of potential WP across all countries. Considering the future, raising WP to 85% of potential WP by 2050, a 100% increase in maize production could be achieved with 20% less planted area and 21% less water consumption than in 2005. Closing the WP gap may be critical to ensuring food security and achieving sustainable global agriculture.

Highlights

Agriculture faces the challenge of ensuring global food security by increasing yield without increasing freshwater consumption[1]
The lowest water productivity (WP) was observed in African countries: Niger, United Republic of Tanzania, Nigeria and Malawi (5.4, 6.1, 10.3 and 10.4 kg ha−1 mm−1, respectively) (Fig. 1c)
Elucidating the nature of WP gaps in global maize production will support the development of strategies to increase agricultural productivity

Summary

Introduction

Agriculture faces the challenge of ensuring global food security by increasing yield without increasing freshwater consumption[1]. WP studies based on site-specific field measurements are often specific to local climate, soil and management practices[15,16]; few studies have focused on mapping global WP. Modeling studies of WP generally do not account for all constraining factors, and may exclude important variables such as management practices, owing to limited data availability and quality[17,18]. Meta-analysis have been developed to integrate quantitatively-available individual field measurements, and are increasingly used in ecological and biogeochemical studies[19,20]. This approach can be used to create a global map of WP in maize production and its response to various factors (e.g., climate, soil properties and agricultural practices) in different regions. There is a growing need for more comprehensive, quantitative analysis of the global factors constraining WP in maize production

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