Effect of sulphur fertilization on yield, sulphur content and uptake by onion¹

Yield, content and uptake of sulphur at successive stages of growth in onion (cv. Faridpuri) were studied on Albaquept soil with 0, 15, 30, 45, 60, 75 and 90 kg S/ha application (each year) during the winter seasons of 1995–96, 1996–97 and 1997–98. Sulphur content, uptake and yield of onion significantly responded to the application of sulphur fertilizer. Sulphur content in leaves at 45 days after transplanting (DAT) and in bulbs at 110 DAT was highest; its content in leaves decreased with advancement in crop age. Uptake of sulphur elements into the leaves increased up to 75 DAT while bulbs uptake continued to increase up to 110 DAT across the treatments. Increasing the levels of sulphur up to 45 kg/ha increased the sulphur content, uptake throughout the season and also produced the highest bulb yield. Zero kg S/ha produced the lowest bulb yield as well as sulphur uptake by the plant.