Influence of Zn on different fractions of S in soil maintained under field capacity moisture regime

Department of Soil Science and Agricultural Chemistry, Orissa University of Agriculture and Technology,

Bhubaneswar-751 003, Odisha, India

E-mail : saren.bckv@gmail.com

Department of Agricultural Statistics, Department of Agricultural Chemistry and Soil Science,

Bidhan Chandra Krishi Viswavidyalaya, Mohanpur-741 252, Nadia, West Bengal, India

Manuscript received 29 September 2016, accepted 13 December 2016

A laboratory investigation was conducted to study the effect of applied Zn on availability of various fractions of sulphur under field capacity moisture regime. The incubation study was conducted with 100 g soil with four levels of S (0, 5, 15 and 20 mg kg^–1) and Zn (0, 0.5, 1.0 and 2.0 mg kg^–1). Soil was sampled and analyzed at 10, 20, 30 and 60th day of the study period for SO₄-S, adsorbed S, organic S, total S and Zn. It was found that, irrespective of doses of Zn and S fertilizers, sulphate sulphur in soils tended to increase significantly with increase in the period of incubation. Addition of Zn fertilizer increases SO₄^2–-S content in soils. Adsorbed sulphur tended to increase significantly with increase in the period of investigation. However on the other hand, organic sulphur tended to decrease significantly with increase in the period of incubation. The decrease in organic sulphur with time is due to mineralization of this fraction of sulphur which is evidenced by the concomitant increase in sulphate and adsorbed sulphur in soils. Total S content slightly increased with increase in the dose of S addition. The increase in total S with added S fertilizer is due to incorporation of available S to the total sulphur pool in soil. Very little variation is recorded in non-sulphate sulphur in soils treated either with Zn or S fertilizer. Addition of Zn did not influence non-sulphate sulphur content in soils. Addition of sulphur fertilizer increased DTPA-extractable Zn in soils. The increment in available Zn is well marked when higher amount of S is added along with higher dose of Zn fertilizer.