The study aimed to improve rice production and economical benefit for the shrimp - rice system in the Mekong delta. The rice experiments were conducted in two consecutive crops in the wet seasons 2012 and 2013 at Phuoc Long district, a saline-affected region, in Bac Lieu province. Two high yielding, short-duration and salt tolerant rice varieties (OM4900 and OM10252) were introduced into the system to evaluate the posibility of replacing a local rice variety (Mot Bui Do-MBD), which has long duration and low grain yield, by shorter-duration varieties. At the start of the cropping seasons, liming and plough were applied to enhance the leaching of salt which accumulated in soil during the previous shrimp cultivation. Results showed that yield and yield components (weight of 1000 grains; grains per flower; filled grains per flower and rice yield) of both OM4900 and OM10252 varieties were significantly higher than those of MBD. It is confirmed that there is possible to replace the local traditional photoperiod sensitive variety (PSV), or Mot Bui Do, with a short-duration (100?105 days), high-yielding variety (HYV) that gives farmers higher profit.

 Keywords: shrimp-rice cropping systems, salt leaching, liming, plough, Mot Bui Do, OM4900, OM10252.