Deficit irrigation an option to mitigate arsenic load in rice grain.

Field trial was carried out during 2008 to assess impact of irrigation on arsenic status of soil, leaf and grain of rice and water use efficiency of the crop. Four levels of irrigation i) continuous ponding (CP); ii) intermittent ponding (IP); iii) saturation and iv) aerobic were imposed to the crop during 15 to 45 days after transplanting (DAT). Rest of the period, irrespective of regimes crop was exposed to CP. Highest grain yield recorded under IP. Arsenic load in soil, leaf and grain attained highest value under CP and decreased in the order of IP>Saturated>Aerobic regimes. Impact of irrigation regimes on variation in total arsenic load was maximum in soil (80.5%) followed by leaf (40%) and grain (18%). Arsenic added to the rice field through contaminated water poses strong relationship with total arsenic status of soil, leaf and grain. Water use efficiency attained highest value under aerobic regime and closely followed by IP.