Southeast Asia is a major rice-producing region with a high level of internal consumption and accounting for 40% of global rice exports.
Limited land resources, climate change and yield stagnation during recent years have once again raised concerns about the capacity of the region to remain as a large net exporter.
Here we use a modelling approach to map rice yield gaps and assess production potential and net exports by 2040. We find that the average yield gap represents 48% of the yield potential estimate for the region, but there are substantial differences among countries.
Exploitable yield gaps are relatively large in Cambodia, Myanmar, Philippines and Thailand but comparably smaller in Indonesia and Vietnam. Continuation of current yield trends will not allow Indonesia and Philippines to meet their domestic rice demand.
In contrast, closing the exploitable yield gap by half would drastically reduce the need for rice imports with an aggregated annual rice surplus of 54 million tons available for export.
Our study provides insights for increasing regional production on existing cropland by narrowing existing yield gaps.
The new millennium has brought a number of challenges to rice systems in Southeast Asia.
First, despite global equilibrium models on food supply and demand previously predicting an abrupt decline in rice demand per capita, we now know that this parameter will remain relatively stable for most countries.
Hence, by 2050, rice demand in Southeast Asia will increase by approximately 18% simply due to population growth.
Second, the two most populous countries in the region (Indonesia and Philippines), totaling nearly 380 million people, depend on rice imports to meet their domestic demand.
Third, after a few decades of a steady increase in average rice yield, there is now evidence of yield stagnation in four of the six major rice-producing countries in Southeast Asia region (Indonesia, Myanmar, Thailand and Vietnam).
Finally, the rice harvested area has remained stable or even declined slightly in some countries recently and is under growing threat of conversion for residential and industrial uses.
Meanwhile, irrigated rice-area expansion is unlikely to occur due to lack of investments in irrigation infrastructure, physical and economic water scarcity and environmental concerns.
Additionally, there is limited scope for further increasing cropping intensity, considering that two and up to three rice crops are now being grown in most of the rice systems in the region.
Although it has been demonstrated that rice yields can be maintained in such intensive mono-culture systems, it has also proven to be very difficult to raise them further, even with the best available varieties and technologies.
Over the past decades, through renewed efforts, countries in Southeast Asia were able to increase rice yields, and the region as a whole has continued to produce a large amount of rice that exceeded regional demand, allowing a rice surplus to be exported to other countries.
At issue is whether the region will be able to retain its title as a major global rice supplier in the context of increasing global and regional rice demand, yield stagnation and limited room for cropland expansion.
Here we follow a data-intensive approach to estimate yield gaps (the difference between yield potential and average farmer yield, Methods) across the major rice-producing countries in the region to determine whether there is still sufficient potential for increasing production on existing land and provide insight on whether the region can remain a major global rice supplier.
Concerns about rice shortages are not new in Southeast Asia. In the early 1960’s, the threat of famine was a major driver for the Green Revolution that resulted in increased cropping intensity, higher yields, lower rice prices and greater food security throughout the region.
The initial step was a steep rise in the harvested rice area during the 1960’s and 1970’s. This was followed by a period of rapid yield increases in the decade from the mid-1970’s to the mid-1980’s due to nearly complete adoption of the first generations of the new rice varieties, associated increases in input use and other technology improvements.
Interestingly, while this initial Green Revolution period ended in the mid-1980s in Indonesia and Philippines, it steadily continued in Vietnam for several decades.
In the 1990’s, concerns were raised about stagnating or even declining yields or total factor productivity in some of the most intensively cropped rice areas of Southeast Asia, reiterating the urgent need for closing existing yield gaps.
The concerns about rice shortages are back now. Our analysis shows that the Southeast Asia region will not be able to produce a large rice surplus in the future with the most recent rates of annual rice yield gains.
Failure to increase yield on existing cropland area will drastically reduce the rice exports to other regions and the capacity of many countries in the region to achieve or sustain rice self-sufficiency.
It also means that many countries in the region would need to rely on regional trade to meet their domestic rice demand, which in itself is not necessarily a disadvantage if rice market liberalization takes place.
Hence, although achieving rice self-sufficiency at the country level should not be taken as the ultimate goal, we note that reaching a reasonable level of SSR for key staple crops is desirable for countries with limited capacity to purchase and distribute large amounts of food imports.
Furthermore, for practically all Southeast Asian countries, rice is of strategic importance in terms of food security, political stability, economy and export potential.
Governments from many countries in Southeast Asia have made explicit their desire to secure stable food prices, completely avoid rice imports in the future and/or increase income from exports.
Our analysis shows that this is possible but only for a scenario where large and strategic investments in agricultural policies, innovation and research and development help accelerate rates of yield gains so that the exploitable yield gap is narrowed down substantially within the next 20 years.
We believe that this is feasible considering that current yield gaps in Southeast Asia are comparably larger than those in other rice-producing countries such as China and the United States, especially in Cambodia, Myanmar, Philippines and Thailand where current yield gaps are 50–70% of yield potential.
Also, we note that the required rates of annual yield gain to narrow down the exploitable yield gap by half are modest in relation to the historical yield gains observed over the past 30 years in these countries.
The importance of maintaining the capacity of Southeast Asia to produce a large rice surplus goes beyond the region as it can help reduce global price volatility and provide a stable and affordable rice supply to many countries in Sub-Saharan Africa and the Middle East.
Nature Food / ABC Flash Point News 2023.