Abstract
A field observation was carried out to evaluate the salt removal performance in a rice paddy due to flooding in Natori city, Miyagi prefecture in September 2013. Salt concentrations in the paddy soil and flooding water were measured by six two-electrode salinity sensors and a soil sampling method for eight days of flooding, respectively. Salt mass content of the soil, Mss, at arbitrary time, t, and depth, z, can be obtained by a statistical analysis. Therefore, the amount of salt mass eluted from the rice paddy, which was calculated from the Mss-t-z relation, was in agreement with the observed value obtained by the sampling method. Salt mass content of flooding water, Msw, increased remarkably in the first three days of flooding, and then the increase rate became gradually smaller with time. It was seen from the present field experiment that 52% of the salt mass in the paddy soil was eluted at the end of flooding period.
