LAUSR

A laboratory investigation was conducted with seven levels of sulphur alone and along with organic manure to study changes in different fractions in the post-harvest soil after Mustard crop. The added Sulphur was dominantly transformed into organic-sulphur in soils and it constituted 40.5-53.1 per cent of the total sulphur present in post-harvest soils. Application of organic manures were able to restrict the leaching loss of S to a great extent. All the fractions of S were in a dynamic equilibrium as evident from correlation studies. All the forms of sulphur except non-sulphate-S were found to be significantly correlated with most of the plant parameters of mustard like S-concentration in seed and straw, S-uptake by seed and straw, total sulphur uptake and available S-content in post-harvest soil, the higher correlation coefficient values being in case of sulphate -S, total water soluble-S and heat soluble-S. Similar correlation was obtained in case of rice crop also. In addition, the rice grain and straw yields also significantly correlated with different S pools. The stepdown multiple regression indicated the importance of sulphate-S, total water soluble-S and organic-S in explaining the variation in mustard and rice yield and yield parameters satisfactorily.