The objective of this project is to evaluate flood management and silicate fertilization on arsenic in rice. In non-flooded rice fields, arsenate, As [V], and silica ions are adsorbed on oxidized iron particles.  When fields are flooded for rice, ferric iron +3 is reduced to the ferrous form +2 releasing As and Si into solution where they can be taken up by rice roots.  In 2012, low yielding rice grown in 2012 with center pivot was Si deficient.  Grain As levels were lower in center pivot rice than flooded rice.  A greenhouse study is being conducted in large soil-filled flood pits.  Treatments are (1) aerobic- no silicon (2) aerobic- with silicon, (3) flooded-no silicon, and (4) flooded with silicon.