1 Radiotracer Laboratory, ANGRAU, ARS, Rajendranagar, Hyderabad-500 030, A.P.
2AICRP on micronutrients, ANGRAU, ARS, Rajendranagar, Hyderabad-500 030, A.P.
3AICRP on fodder crops, ANGRAU, ARS, Rajendranagar, Hyderabad-500 030, A.P.
4AICRP on Castor, Regional ARS, Palem-Mahaboobnagar, A.P.
An investigation was carried out to find the effect of split application of S on yield and use efficiency by soybean using S-35 radioisotope on marginal S status soil. Irrespective of the level, sulphur application in two equal splits as basal and at 30 DAS made a significant dent on seed yield of soybean compared to its one time application either at sowing or at 30 DAS. The mean seed yield of Soybean was highest (1643 kg/ha) when S was applied in two splits (1/2 as basal + ½ at 30 DAS) followed by full dose as basal (1513 kg/ha) and at 30 DAS (1395 kg/ha). It was found that a minimum of 30 kg S/ha is needed to obtain good yields of soybean although higher level of its application had beneficial effect on the crop, albeit, to an extent of 4–5% for increase of sulphur to 40 kg/ha. Sulphur application in two equal splits as basal and at 30 DAS has increased the S use efficiency in soybean seeds by 128.6 and 150.7% compared to single time application either as basal or at 30 DAS, respectively. Though the utilization of applied S by soybean was found to be higher at 30 kg S/ha level (16.8%) compared to 40 kg S/ha(14.60%) the difference was not much.
Soybean, S nutrition S requirement and S use efficiency
