Garlic, Allium sativum, is known for its health benefits. Besides antioxidants and flavonoids which are helpful to combat stress, garlic contains organosulphur compounds, such as allicin, that give garlic its typical pungent flavour.
Besides allicin, there are other sulphur compounds, such as allyl methyl thiosulfinate and allyl trans-1-propenyl thiosulfinate, with similar bioactivity.
Can sulphur application improve the biochemical quality of garlic? What is the optimum sulphur fertiliser dose per hectare to increase garlic productivity?
To answer these questions, A Thangasamy and team from two ICAR national research institutes conducted a series of experiments at the Directorate of Onion and Garlic Research, Pune.
On tenth November, they planted 800 garlic plants in twelve square metre plots. They had six such plots where they applied sulphur in the form of bentonite at different rates, starting from nil and increasing it by 15 kilograms per hectare in different plots. All plots were otherwise given the same treatment in terms of fertilisers, weeding and other practices. And the crop was harvested in the last week of March for measurements and analysis.
After three years of experiments, the scientists observed that sulphur application of up to 30 kilograms per hectare increased garlic yield considerably. With further increase in sulphur dose, the biochemical quality increased but not the garlic bulb yield.
Total protein content increased with sulphur application of up to 60 kilograms per hectare, while antioxidant activity increased only till up to 45 kilograms of sulphur per hectare.
Allicin and other major sulphur containing compounds with bioactivity increased with sulphur application. Sulphur fertilisation also helps the plants cope with stresses such as high temperature.
The researchers recommend an optimal dose of 45 kilograms of sulphur per hectare to enhance the quality and productivity of garlic in sulphur-deficient soils and 30 for normal soils. Farmers can now get their fields’ soil tested and apply sulphur to their garlic crops based on the recommendations for getting higher yield with better quality.
STEAMindiaReports: Delicious and spicy science news stories
Free for Indian media to use
* This report was written in a workshop on science writing organised by Current Science