Closing yield and harvest area gaps to mitigate water scarcity related to China's rice production

Over the past decades, China's rice production area has experienced a substantial change in spatial distribution that has exacerbated national freshwater scarcity. To support the development of guidelines for sustainable water use in rice cropping, this study explores the potential for achieving a downscaled freshwater use boundary with high spatial resolution while maintaining China's current production levels. We found that, to operate within the boundary, which was defined using a water scarcity index, national irrigation water use for rice cropping should reduce by 10% in water-scarce regions, implying a 10% loss in national rice production without further intervention. However, using scenario analysis, we found that the production losses can be reduced to approximately 7% by closing yield gaps, and fully compensated by closing harvest area gaps in water-rich regions. The closing of both the yield and harvest area gaps allows an increase of 6.9 million metric tons of rice (3% of the national production). The water-rich regions which are suitable for double-rice systems show a high potential to increase rice production. The spatial redistribution of rice production under these scenarios resulted in a reduction in the national water-scarcity footprint related to rice cropping of 52-55%. These results demonstrate that, to reach the downscaled water use boundary, national redistribution of rice production is necessary and urgent. Our study provides detailed spatial information to support water and land use decisions.Industrial Ecolog

Balancing food production within the planetary water boundary

Freshwater use is recognized as one of the nine planetary boundaries. However, water scarcity is a local or regional phenomenon, meaning that the global boundary must be spatially downscaled to reflect differences in water availability. In China, as in most countries, irrigation is the major freshwater user, closely linking food security to the freshwater boundary. To provide evidence supporting environmentally sustainable water use in China's food production, this study explores how a grain production shift affects the national water-scarcity footprint (WSF) and the potential to reach sustainable water use limits while maintaining the current grain production level. We found that the historical breadbasket shift towards water-scarce northern regions has increased the WSF by 40% from 1980 to 2015. To operate within the boundary, national irrigation needs to be reduced by 18% in hotspot regions, with implications of a 21% loss of grain production. However, this loss can be reduced to around 8% by closing yield gaps in water-rich regions. It demonstrates the high potential of integrating crop redistribution and closing yield gaps to achieve grain production goals within freshwater boundaries. This Chinese case study can be representative of the challenges faced by many of the world's countries, where pressures on land and water resources are high and a sustainable means of increasing food supply must be found. (C) 2020 The Author(s). Published by Elsevier Ltd.Industrial Ecolog

Water-scarcity footprints and water productivities indicate unsustainable wheat production in China

Water shortage is a critical constraint limiting China’s capacity for food security. To provide evidence supporting environmentally sustainable water use in food production, this study compared irrigation water productivities (IWPs) and water-scarcity footprints (WSFs) for China’s wheat production at high spatial resolution. Contrary to previous water productivity studies assessing crop yield over total water consumption, it was found that IWPs in China’s water-scarce northern regions were much lower than those in water-rich southern regions. The WSFs further demonstrated the larger environmental impacts resulting from irrigation in water-scarce northern regions. Hotspot regions, having IWPs in the lowest tercile (−3) and WSFs in the highest tercile (>0.058 m3 H2Oe kg−1), were mainly located in the Huang-Huai-Hai and northwestern regions and accounted for 34% of the cropping area but 61% of irrigation water use. Historically, the south was also an important contributor of China’s wheat production, but progressive shifts toward highly resource-efficient cropping in the Huang-Huai-Hai region has occurred. The paradox is that gains in total crop water efficiency have led to increased irrigation demand and water scarcity. Today, croplands suitable for wheat production lie fallow in some southern regions in the winter. A national reassessment of this situation is urgently needed.Industrial Ecolog

A glimpse of the future in animal nutrition science. 1. Past and future challenges

If the world population continues to increase exponentially, wealth and education inequalities might become more pronounced in the developing world. Thus, offering affordable, high-quality protein food to people will become more important and daunting than ever. Past and future challenges will increasingly demand quicker and more innovative and efficient solutions. Animal scientists around the globe currently face many challenging issues: from ensuring food security to prevent excess of nutrient intake by humans, from animal welfare to working with genetic-engineered animals, from carbon footprint to water footprint, and from improved animal nutrition to altering the rumen microbiome. Many of these issues are most likely to continue (or to exacerbate further) in the coming years, but animal scientists have many options to surmount the obstacles posed to the livestock industry through tools that are presently available. The frequency, interval, and intensity of livestock impacts, however, differ across regions, production systems, and among livestock species. These differences are such that the generalization of these issues is impossible and dangerous. For instance, when we discuss domesticated ruminant nutrition in the human food context, we look for the most efficient ruminant feeds that complement, rather than compete with, grains grown for direct human nutrition. Greater scrutiny and standardization are needed when developing and validating methodologies to assess short- and long-term impacts of livestock production. Failure in correctly quantifying these impacts may lead to disregard and disbelief by the livestock industry, increased public confusion, and the development of illusionary solutions that may amplify the impacts, thereby invalidating its original intent