Influences of Geological Conditions on the Soil Environment in Paddy Fields under Saturated Irrigation

Abstract

  In an attempt to counter heat damage to rice plants, the influences of geological conditions in paddy fields on the subsurface water flow and soil temperature for saturated irrigation are clarified by simulating the soil water movement and heat transport. Considering paddy fields located in a lowland or an alluvial fan as the geological conditions of the target area, the simulations of the water movement and heat transport in soil are carried out over 20 days, corresponding to the ripening period of rice grain. The results indicated that the time-varying soil temperatures and the average soil temperature of the lowland paddy field were lower than those of the alluvial fan, and thus the effect of saturated irrigation depends on the geological conditions of paddy fields under its implementation.