Abstract
Effects of excessive-water stress on corn root and its nitrogen content were investigated in environmentally controlled growth chambers. Two excessive water treatments (surface-submerged at 3-cm depth and water table at 15-cm beneath the soilsurface) each with four excessive-water stress levels (equivalent to 90, 180, 270 and 360 cm-days of stress as defined by SEW30concept) were imposed 23 days after plant emergence in the crop establishment stage. Data on root distribution, root length, root dry matter and root nitrogen content were compared for the both water table positions. Corn roots were significantly larger when water table was maintained at the 15-cm depth than when the surface wasubmerged at all excessive-water stress levels. Excessive-water stress resulted in higher nitrogen content (%) in root dry matter but smaller root nitrogen per plant for surface-submerged treatment compared with 15-cm water tabletreatment. The overall results of the study conclude that lowering the water table position from the surface submergence to beneath the soil surface may be a useful practice to avoid significant loss of crop in poorly drained soils.
