A Critical Review on Sulphur Application in Rapeseed-mustard to Enhancing Productivity and Oil Quality

Abstract

Sulfur (S) plays a vital role in determining the seed yield, oil content, quality, and resistance to various stresses in rapeseed-mustard. It is essential for chlorophyll formation, oil synthesis, seed protein, amino acids, enzymes, and glucosinolate in these plants. Sulphur also boosts mustard seed production. However, due to modern agricultural practices, including multiple cropping, the use of sulfur-free fertilizers, and limited organic manure application, soil sulfur levels are depleting rapidly in India. Indian soils typically contain between 10 to 6319 mg kg-1 of sulfur, with most agricultural soils averaging 30 to 300 mg kg-1. Adding sulfur increases mustard oil content by enhancing the activity of an enzyme called acetyl-CoA carboxylase, which is essential for oil synthesis. Sulfur also mitigates the harmful effects of heavy metal toxicity, especially from cadmium. Sulfur interacts with other nutrients in both positive and negative ways. Recommendations for sulfur fertilization in different mustard growing regions have been made based on various research programs. To maximize sulfur use efficiency, it's crucial to apply the correct amount based on soil tests and in balance with other limiting nutrients. Timing of sulfur application is also important; it's best applied at the beginning but can also be top-dressed 20-40 days after planting for optimal yield. Research suggests that mustard responds well to foliar spraying of thiourea during flowering and basal placement before sowing. This paper reviews the strategies to improve sulfur utilization through advancements in application rates, methods, and sulfur sources on rapeseed-mustard.