Effect of sulfur application on soil sulfur (SO4-S) status in different textured soils of Pothwar

The effect of S application on soil sulfur (SO4-S) contents was investigated in different textured soils. The samples from eight soil series viz. Missa, Rajar, Qutbal, Guliana, Tirnaul, Rawal, Rawalpindi and Qazian of Pothwar area were collected and analyzed for physico chemical characteristics. Only two soil series i.e. Missa and Rajar had satisfactory (11-30 mg kg^-1) S contents at upper soil depth while the rest were deficient ( 10 mg kg^-1) in sulphur. The highest SO4-S content (15.2 mg kg^-1) was recorded in Missa soil, bearing clay loam, while lowest (5.4 mg kg^-1) in Qazian soil bearing loamy sand soil texture at upper (0-15 cm) soil depths. The three soils deficient in SO4-S viz. Guliana, Rawal, Qazian, were selected for a pot experiment. Sulfur was applied @ 0, 5 and 15 kg S ha^-1 using gypsum and ammonium sulphate (AS) as sources. The highest biomass (14090 kg ha^-1) was observed with AS @ 15 kg S ha^-1 application. The post harvest soil analysis revealed that the S application significantly increased soil SO4-S contents; the highest 9.49 mg kg^-1 was observed where gypsum @ 30 kg S ha^-1 was applied. The application of gypsum and AS @ 30 kg S ha^-1 increased SO4-S contents by 8.5 and 7.60 % over control, respectively. The highest mean SO4-S contents (6.40 mg kg^-1) were observed in Guliana soil having silt loam texture while lowest (4.64 mg kg^-1) in Qazian soil. The results concluded that well drained, light textured soils in high rainfall areas have low SO4-S content and require S fertilization for optimum crop production.