Garlic's pungent odor may be great for warding off vampires, but it is also an indication of its healthfulness. Allicin is one of the main sulfur compounds in garlic that is responsible not only for its bite, but also for its reputed health benefits. Allicin is produced when the compound alliin in raw garlic mixes with the enzyme alliinase after garlic is chopped or crushed.
New research has shown that the type and amounts of fertilizer applied to garlic can significantly alter the amount of alliin that it develops. As described in the November-December 2010 issue of HortIdeas, field trials done in Germany showed that the concentration of alliin went up proportionally with an increase in sulfur fertilization and went down slightly as nitrogen fertilization increased. Researchers concluded that sulfur added to soils that were low in this nutrient would increase the concentration of alliin in garlic. They also suggested that keeping nitrogen fertilization moderate would increase alliin levels, in addition to making garlic less susceptible to fungal infection.