A roadmap for securing a larger and greener global rice bowl

Rice systems face the dual challenge of producing more and being more efficient in the use of water, labor, nutrients, and pesticides. An article published in Nature Communications on Dec 9 assessed performance of 32 rice cropping systems, altogether accounting for 50% of global rice cropland.

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Harvest of a rice field in Java, Indonesia. Up to three rice crops can be grown during the same year in tropical regions. Courtesy photo: Nanyan Deng

Rice is the main staple food for more than half of the global population, and as the world population grows, demand for rice is expected to grow, too.

 But increasing the global rice production is not a simple prospect.

 “Global rice production is challenged now due to the negative environmental impact, water scarcity, labor shortage, and slack of yield increase in many parts of the world,” said Dr. Shen Yuan, a postdoctoral research associate at Huazhong Agricultural University in China who spent two years as visiting scholar at University of Nebraska-Lincoln working on this project.

 The challenge is, therefore, how to produce more rice on existing cropland, and do so while minimizing the environmental impact.  New research led by Dr. Shaobing Peng, a professor of agronomy at Huazhong Agricultural University and Dr. Patricio Grassini, an associate professor of agronomy at University of Nebraska-Lincoln and co-leader for the Global Yield Gap Atlas (www.yieldgap.org), provides an analysis of roadmaps toward sustainable intensification for a larger global rice bowl. The research was published Dec. 9 in Nature Communications.

“Comparing rice cropping systems around the world in terms of productivity and efficiency in the use of applied inputs can help identify opportunities for improvement” Grassini said.

 The global assessment was led by Huazhong Agricultural University and University of Nebraska-Lincoln, in collaboration with partners from other 11 institutions, including U.C Davis & Texas A&M AgriLife Research Center in USA, the International Rice Research Institute (IRRI), Africa Rice Center,  the Indonesian Center for Rice Research (BB Padi) &  Assessment Institute of Agricultural Technology (AIAT) in Indonesia, Federal University of Santa Maria & EMBRAPA Arroz e Feijão in Brazil,  the National Institute of Agricultural Research (INIA) in Uruguay, and the Indian Institute of Farming Systems Research (ICAR) &  Indian Institute of Water Management in India. The study assessed rice yields and efficiency in the use of water, fertilizer, pesticides, and labor across 32 rice cropping systems that accounted for half of global rice harvested area.

 “This study is the most comprehensive global evaluation of production system for a major staple crop that I am aware of, and it will set the standard for future global comparison of such system.” said Kenneth G. Cassman, a co-author of the paper and an Emeritus Professor at University of Nebraska-Lincoln.

Transplanting of a rice field in Indonesia. Rice production is labor intensive, especially in cropping systems that rely on manual labor. Courtesy photo: Jose Andrade.

 The good news, according to the study, is that there is still substantial room to increase rice production and reduce the negative environmental impact.

 “Around two-thirds of the total rice area included in our study have yields that are below the yield that can be attained with good agronomic practices” said Dr. Yuan. “Closing the existing yield gap requires better nutrient, pest, soil, and water management, reduction of production risk, and breeding programs that release rice cultivars with improved tolerance to evolving pests and diseases”, he added.

 Another important finding from the study is that meeting food production and environmental goals are not conflicting goals.

 “We found that achieving high yields with small environmental impact per unit of production is possible” said Professor Peng. “Indeed, there is room for many rice systems to reduce the negative impact substantially while maintaining or even increasing rice yields”, he added.

 Meeting the dual goal of producing more and minimizing the environmental footprint is an enormous challenge. “Improved agronomic practices, complemented with proper institutions and policy can help make rice cultivation more environmentally-friendly,” said Professor Grassini. “Our study makes a first step in identifying systems with largest opportunities for increasing crop yields and resource-use efficiency, providing a blueprint to orient agricultural research and development programs at national to global scales”. 

Patricio Grassini

Associate Professor, University of Nebraska-Lincoln