Press Release January 2000

Recent developments in rice production technology as well as new economic trends, however, are encouraging farmers to shift from traditional transplanting to direct seeding. This change in sowing method is expected to have a big impact on Asian rice production efforts and on the region's economies.

This is because one of the main forces driving such changes has been shrinking resources in the region, especially available land and water. In theory, the more widespread the introduction of direct-seeding techniques, the more land and water are conserved.

Direct seeding is already the dominant sowing method used by farmers in Sri Lanka and Malaysia. Its importance as a leading method of crop establishment has also increased during the past three decades in the Philippines, Thailand, and the Mekong Delta in Vietnam. Transplanting, however, remains the major method used in other rice-producing countries in the region.

Sowing dry seeds on dry or unsaturated soil is called dry seeding, whereas wet seeding involves sowing pregerminated seeds on puddled soils. In both cases, seeds are sown directly; thus, the dry- and wet-seeding methods are often jointly referred to as direct seeding. Traditional transplanting, on the other hand, involves replanting rice seedlings grown in nurseries.

Agricultural economist Sushil Pandey and assistant scientist Lourdes Velasco from the Philippine-based International Rice Research Institute (IRRI) said the trend toward direct seeding has been brought about by "rising wage rates, a growing scarcity of water, the improved availability of chemical weed control agents, and the increasing intensification of rice land."

Dr. Pandey and Ms. Velasco further stressed that the shift in farming methods has also been encouraged by the availability of high-yielding, short-duration varieties that have made the double cropping of rice in humid tropical Asia feasible for the first time--especially where irrigation during the dry season could be developed.

"The expansion in double-cropped rice area also increased the demand for labor," they said. "At the same time, countries in East and Southeast Asia, where the pace of economic growth has been the most rapid, were already facing escalating farm labor costs as traditional laborers found other better-paying work. Also, the direct seeding of short-duration varieties facilitated crop intensification through the double cropping of rice in some rainfed areas. These factors, combined with the availability of chemical weed control methods, have helped encourage the use of direct seeding in tropical Asia."

Dr. Pandey and Ms. Velasco stressed, however, that the importance of direct seeding and transplanting varies among regions and ecosystems.

"Traditional direct-seeding systems with low productivity dominate in some areas, while successful transformations to high productivity systems have occurred in others," they said. "It also appears that the transplanting culture may continue to retain its dominance under certain environmental and socioeconomic conditions."

Dr. Pandey and Ms. Velasco are two of 14 IRRI scientists participating in a four-day international workshop on Direct Seeding in Asian Rice Systems: Strategic Research Issues and Opportunities, which opens tomorrow (25 January) in Bangkok. They will discuss their paper titled Patterns of changes in rice establishment methods in Asia: the economic and demographic driving forces.

Fifty-eight scientists from IRRI, Australia, Bangladesh, Cambodia, China, France, India, Indonesia, Japan, Laos, Malaysia, Nepal, Thailand, the United Kingdom, the United States, and Vietnam will attend the workshop, which is being organized by IRRI and the Rice Research Institute of Thailand. Dr. Vethaiya Balasubramanian and Dr. James B. Hill, also of IRRI, will speak on Direct seeding of rice in Asia: emerging issues and strategic research needs for the 21st century.

During the workshop, scientists will assess how environmental conditions influence farmers' choices of direct-seeding techniques and the impact of direct seeding on rice cultivation in Malaysia and elsewhere. They will also analyze direct-sowing practices in rainfed lowland areas in southern Thailand and look at the economic aspects of pregerminated direct-seeding methods.

In addition, the scientists will consider the effect of seed rates and seeding methods in the wet-seeded rice culture in the alluvial soils of the Mekong Delta. They will also focus on germplasm improvement by determining the cultivar requirements of direct-seeded rice in rainfed lowlands, the manipulation of seed and seedling vigor, as well as the implications for the performance of wet-seeded rainfed lowland rice.

Other important areas for discussion will include water and nutrient management, especially direct dry seeding for water savings in irrigated rice production systems, increasing water productivity in rice cultivation, and nutrient management in direct-seeded rice under different ecosystems.

back to top