Tuesday, November 6, 2007 - 2:45 PM
147-2

Arsenic Contamination of Soils Reduces Rice Yields in Bangladesh.

G. M. Panaullah, CIMMYT Office in Bangladesh, Dhaka, Bangladesh, John Duxbury, Crop and Soil Sciences, Cornell University, Ithaca, NY 14853, Julie Lauren, Tower Rd., Cornell University, Cornell University, 917 Bradfield Hall, Ithaca, NY 14853, Craig Meisner, Cornell University, 904 Emory Dr., Chapel Hill, NC 27517, and Richard H. Loeppert, Soil & Crop Sciences, Texas A&M University, College Station, TX 77843-2474.

 


The Ganges-Meghna-Brahmaputra groundwater aquifer, which is contaminated with As, is the sole source of drinking water and also a major source of irrigation water in Bangladesh. Approximately 60% of the 140 million people of Bangladesh are at risk from As-contaminated drinking water. An additional, long-term risk is the potential loss of agricultural sustainability. Intensive irrigation of rice, the staple food crop of Bangladesh, with As-contaminated groundwater is increasing the soil As level in many areas of Bangladesh. In a survey across Bangladesh we found severe As contamination in  south-western, central and south-eastern districts. A major concern, related to the vital issue of food security in the country, now, is whether high water-soil As is affecting rice production. We conducted a 2-year (2006 and 2007) irrigated winter rice (locally known as Boro) experiment in farmers’ fields in Faridpur, a badly As-affected district in the Gangetic Floodplain of central Bangladesh. A shallow tube well command area (water As, 130 µg L-1) with soil As levels varying from 11 to 56 mg kg-1 was selected to study the effect of naturally occurring As in irrigation water and soil on rice yield. In both years, the yield of a popular Boro variety, BRRI Dhan 29, decreased consistently and drastically from 7-8 t ha-1 (rough rice) to 2-2.5 t ha-1 as the soil As level increased from 11 to 56 mg kg-1. This year (2007) we observed that with high total soil As, there could be enough bio-available As to adversely affect the growth and yield of relatively "safe" upland crops like wheat and maize. Using the national soil and irrigation-water As databases and results of the rice yield experiment, we predict substantial rice production decreases with continued use of high-As groundwater for irrigation. This study indicates the importance of developing As management technologies for sustainable crop production and a national policy of irrigation-water management in Bangladesh.