Effect of Soil Application of Gypsum as a Sulphur Source on Yield and Quality of Onion (Allium cepa L.)

Onion (Allium cepa L.) is a sulphur-loving crop, yet sulphur nutrition is often neglected by farmers, leading to sub-optimal yield, quality, and profitability. A diagnostic survey conducted in Fatehabad district of Haryana revealed that farmers primarily relied on diammonium phosphate (DAP) for phosphorus nutrition and used costly foliar sprays for sulphur application. The present study aimed to find a cost-effective sulphur management strategy. On-farm trials were conducted during the Rabi seasons of 2022–23 and 2023–24 in the adopted villages of Fatehabad district. Two treatments were compared: farmer’s practice (DAP @ 108 kg ha⁻¹ without sulphur) and soil application of gypsum @ 5 bags ha⁻¹ along with DAP @ 108 kg ha⁻¹. Results showed that soil application of gypsum significantly improved crop growth, bulb size, pungency, keeping quality, and yield over the farmer’s practice. Onion yield increased by 10.7% and 12.5% during 2022–23 and 2023–24, respectively. Higher net returns (₹328,300 ha⁻¹ and ₹139,500 ha⁻¹) and benefit–cost ratios (4.26 and 3.81) were recorded under gypsum application despite a marginal increase in the cost of cultivation. The study concludes that soil application of gypsum is an economical, effective, and sustainable source of sulphur for onion cultivation and should be preferred over costly foliar sulphur sprays to enhance productivity, profitability, and soil health.