Abstract
There are many paddy fields in the Ariake seaboard. The paddy fields are added fertilizer included Si and paddy rice absorbed dissolved Si (DSi). Therefor, Si loads in inflow and outflow were estimated in two paddy fields (C and D) in order to evaluated DSi loads from the land to Ariake Sea. Si loads in inflow of C and D were 71 and 44 g/m2 and Si loads in outflow of paddy field C and D were 100 and 40 g/m2. The fertilizer included Si accounts for a large percentage in Si load in inflow and the absorption by paddy rice accounts for a large percentage in Si load in outflow. There are much amount of Si absorption by paddy rice in paddy field C than it in paddy field D, because that the soil of paddy field C may include much available Si than it in paddy field D. Si loads in outflow by overflow to Si loads in inflow from a pond are 16 -42 %. Therefore, DSi load in inflow from water bodies may decreases through a paddy field.
