Rice Straw Management by Farmers in a Triple Rice Production System in the Mekong Delta, Viet Nam

Abstract

A triple-rice-cropping system is widespread in the Mekong Deltr, and not only are 21 million tons of rough rice (in 2008) produced annually but also 24 million tons of straw mass (dry weight) are estimated to be generated annully. The management of this straw has the potential to influence sustainable agronomic productivity of the region as well as global warming. This study was conducted to understand the present management of rice straw in the system. In a typical triple-rice-cropping system in Can Tho, Viet Nam, located in the centre of the Mekong Delta, interview surveys of 50-household farmers on their uses of traw in 2007-2011 and 35-household farmers on their uses of straw and yields of rice grain and straw from September 2011 to November 2012 were conducted. Almost all (100%) of the straw harvested in the winter-spring cropping seasons was burned. However, the incineration ratios of subsequent cropping seasons (spring-summer and summer-autumn) decreased to 22% and 1&, respectively. The incineration ratios of harvested straw tended to become lower when the precipitation was high at harvest time. Most of the straw that was not burned was removed froin the paddies and was utilised as mushroom beds (69% in spring-summer and 71% in summer-autumn). Thus, the use of rice straw seems to be passive in the area at present, i.e., the farmers burn the strw when it can be burned easily; however, to enhance the region's sustainable agronomic productivity, there must be further study on the use of the straw thet is currently burned.