Available sulphur and response to its application by raya (Brassica juncea) and residual effect on summer Moong (Phaseolus Mungo) in alluvial soils of Punjab

Available sulphur content of 2500 surface soil samples collected from 25 villages varied from 0.04 to 504 (2003) and 7.9 to 383 (2004) mg S kg⁻¹. About 2, 3 and 95%samples in 2003 and 11, 18 and 71% samples in 2004 were deficient, medium and high, respectively. Field experiments were conducted on deficient or nearly deficient soils, to evaluate the response of raya to direct application of sulphur and residual effect of applied sulphur on moong crop at five locations in different villages, of Punjab during 2003 - 04 and 2004 - 05. The raya grain yield increased significantly with the application of sulphur at all the five locations. The per cent increase in grain yield of raya varied from 49.8 to 66.8 in 2003 and from 25.3 to 43.3 in the second year. The residual effect of sulphur on grain yield of moong was small. The sulphur uptake varied from 14.1 to 71.1 (2003) and 16.9 to 60.5 kg ha⁻¹ (2004) in raya and from 4.0 to 10.0 (2003), 2.9 to 10.8 kg ha⁻¹ (2004) in moong with different levels of sulphur application. On an average oil content and oil yield of raya varied from 36.6 to 37.9% and 387 to 568 kg ha⁻¹. The contribution from underground water (4 irrigation) varied from 12 to 27 kg S ha⁻¹ at different locations. The benefit to cost ratio of application of sulphur to raya varied from 9.2: 1.0 to 18.9: 1.0 and to moong crop from 1.2: 1.0 to 3.8: 1.0 at different levels of sulphur application. There was not much change in sulphur status of the soil after the harvest of the crops.