The study of acid sulphate soils of Kerala, India, which has the twin problem of acidity and salinity, revealed that many of the crop growth parameters in the experimental area, particularly the grain yield and 100-grain weights were significantly superior to that of the control plot when subsurface drainage was provided. Subsurface drain spacing up to 30 m can significantly improve the productivity of the area. Wider spacing than 30 m may have to be explored by conducting further experiments.