What drives the roughly six-year cycle in white sugar prices?

What drives the roughly six-year cycle in white sugar prices?
Roughly 90% of sugar comes from southern cane and about 10% from northern beet, so the price cycle largely mirrors the cane planting cycle of three to four years. Cane is a perennial ratoon crop: once planted, it can be harvested for several years without replanting, so farmers do not switch crops quickly when prices fall. That biological rigidity delays supply response, amplifying swings. China produces about 10 million tons against demand of 14 to 15 million, leaving a 4 to 5 million ton gap filled by imports, mainly from Brazil and India. Export restrictions in those origins tighten the domestic balance and can push futures sharply higher.