Sri Lanka, Nov. 7 -- A tea bush planted today may take five years to produce a crop, a decade to generate meaningful returns and more than 20 years to repay the investment. Yet Sri Lanka'smregional plantation companies have only 19 years remaining on their leases. This is the contradiction at the heart of the country's plantation economy: an industry whose future depends on long-term investment is operating within a policy framework that makes such investment increasingly difficult to justify.

The stakes extend well beyond the estates. According to the World Bank, Sri Lanka's wider agrifood system accounts for roughly one-sixth of national output, supports over 40% of employment and contributes nearly 30% of goods exports. Within planta...