Sulphur Status and Response of Rice to Sulphur on Some Soils of Andaman and Nicobar Islands

Sulphur status of soils growing rice in Andaman and Nicobar Islands was evaluated through soil and plant tests. Several methods of extracting soil sulphur were compared. Among the chemical procedures used, the CaCl₂, 16 mM P and acetate buffer methods were equally suitable as an index of plant available sulphur. HI reducible S. carbon bonded S and arylsulphatase activity were not suitable for using as an indicator of plant available sulphur. Of the 20 soils tried, 15 gave marked response to sulphur fertilization. The critical levels of soil sulphur determined by these methods could provide sufficient sulphur in these humid tropical soils and ensure 0.175% sulphur in rice plant at 40 days after planting.