RESPONSE OF RAPESEED (Brassica juncea L.) TO VARIOUS SOURCES AND LEVELS OFSULPHUR IN RED AND LATERITIC SOILS OF WEST BENGAL, INDIA

Field experiments conducted on rapeseed (Brassica juncea L.) during 2000-2001 and 2001-2002 in a typical lateritic soil (Alfisol) of West Bengal, India revealed that sources viz. single superphosphate, phosphogypsum, pyrites and elemental S and levels of sulphur (0, 20, 40, 60 kg S ha-1) have significant influence on grain yield, total biological yield, sulphur concentration in grain and stover, total sulphur uptake, grain protein content, oil content and oil yield. The maximum grain yield (16.39 and 17.15 q ha-1) was recorded with SSP followed by phosphogypsum (16.08 and 16.91 q ha-1) and pyrites (15.23 and 16.12 q ha-1) @ 45 kg S ha-1 during both the years. The lowest yield was observed with elemental S. S concentration in grain and stover of rapeseed increased with increasing levels of S. The highest S uptake (28.51 and 29.13 kg S ha-1) @ 60 kg S ha-1 was noticed with single superphosphate followed by phosphogypsum (25.95 and 28.92 kg S ha-1), pyrites (24.92 and 26.32 kg S ha-1) and elemental S (22.37 and 23.11 kg S ha-1) during both the years. The highest oil yield (6.93 and 7.37 q ha-1) was obtained at the application of 45 kg S ha-1 with single superphosphate followed by phosphogypsum (6.78 and 7.25 q ha-1) and pyrites (6.37 and 6.89 q ha-1) during both the years. However, the decreasing trend of oil content in seeds besides higher oil yield due to higher levels of S application to soil was noticed. Amongst the various sources of S tested, single superphosphate was the best with respect to grain yield, oil yield and protein content, S recovery and crop response followed by phosphogypsum, pyrites and elemental S. However, elemental S also responded well at higher level (i.e. 60 kg S ha-1) under consideration. Sulphur sources also improve the availability of S in soils after the harvest of the crop.