Sulphur in Crop Productionin Suthern Telangana Zone of Andhra Pradesh

摘要

Studies on sulphur status of soils and crop responses to applied sulphur were carried out on Alfisol and Vertisols of Southern Telangana zone of Andhra Pradesh. In profiles of Alfisol and Vertisols of certain districts, the total S-contents ranged from 98 to 310 ppm and 100 to 387 ppm respectively, showng an increase with increase in depth of soils. The inorganic SO_4~(2-)-S for med 2.5 to 20.0 per cent of total S; the rest being non SO_4~(2-) plus organic S. Among the chemical extractants, 0.15% CaCl_2 was found superior to others while the fungus Aspergillus niger extracted very low contents of available S. Pulse and oilseed rops showed responses to applied S; the magnitude of response being variable showing a dependence on native S status. Sulphur utilization studies were carried out employing tracer techniques. Sunflower showed highest response with S applied as ammonium sulphate shereas residual effects were maximum with gypsum. The crop required application of 40 and 60 kg S ha~(-1) in Vertisol and Alfisol and Alfisol respectively. Among sunflower based cropping ssytems, sunflower-greengram was found to be the best. The sunflower seed yield was maximum when N:S ratio in plant was 10:4. Castor crop showed maximum response with applied S at 40 kg ha~(-1)as ammonium sulphate while sesamum showed response at 60 kg ha~(-1) applied through gypsoum uder field conditions. Sulphur application also improved the quality parameters viz.,crude protein and oil contents of seeds. Antagonism was observed between S and Mo applied to groundnut.