Alternate wetting and moderate soil drying increases grain yield and reduces cadmium accumulation in rice grains

BACKGROUND: Rice is the most important staple food in Asia but has also been identified as one of the major sources of cadmium (Cd) intakes for some Asian population. This study investigated whether grain yield could be maintained but Cd in grains be reduced through proper irrigation management when rice was grown in Cd-contaminated soil. RESULTS: Compared to the well watered treatment, the alternate wetting and moderate soil drying (MID, re-watered when soil water potential decreased to -20 kPa) increased grain yield by 10-12% and improved milling and appearance quality of rice when grown in a soil containing a water-soluble Cd content of 18 g kg(-1). An alternate wetting and severe soil drying (SD, re-watered when soil water potential decreased to -40 kPa) showed an opposite effect. Both MD and SD significantly increased Cd content in roots while they reduced it in the straw. MD reduced Cd content by 19-21% in the grain and by 40% in milled rice. The SD significantly increased Cd content in the grain but reduced it in milled rice. CONCLUSION: An alternate wetting and moderate soil drying could increase rice yield and quality and also reduce Cd in the diet of rice. (C) 2009 Society of Chemical Industry