Direct and residual effects of sulphur in cotton-wheat cropping system in sandy loam soil

摘要

A field study on the direct and residual effects of applied sulphur 30kg/ha as elemental sulphur on cotton - wheat cropping system were evaluated in two consecutive years, viz .1998-99 and 1999-2000, at Central Institute for Cotton Research, Regional Station, Sirsa. An increase of seed cotton yield by 10 % and wheat grain by 11% with the addition of 30kg S/ha over no sulphur was found in the first year (1998-99). Significant effect of residual S on wheat yield and significant increase in yields of both crops were observed by cumulative S in the second year. Pooled data indicates that seed cotton yield was increased from 14.9 to 17.1q/ha (16%) while wheat grain yield increased from 22.4 to 26.4 q /ha (18%). Higher magnitude of increase in wheat grain yield (20%) was observed due to cumulative effect of S, in which a total of 120kg S/ha was received in four seasons in same plot. With an increase in sulphur supply, the S content in cotton seed and wheat grain increased progressively. The S concentration of leaf of cotton and wheat increased from 0.21 to 0.50% and 0.13 to 0.19% respectively, by the addition of S 30 kg /ha as cumulative. At the end of second year, S build up from 7.5 to 9.6 mg/kg soil was noticed due to cumulative effect of S. Higher economic return was received by direct and residual sulphur in both the crops and least benefit was received in the plot where S was applied once to the crop.