New Delhi, March 9 -- Manu Yaw Fofie was born into the cocoa farming business, but the land bequeathed to him has become more of a burden than a blessing. A sharp fall in cocoa prices over the past year has left beans rotting in some West African warehouses, while global chocolate makers scramble for supplies and consumers seek their fix.

With less money coming in, the 52-year-old Fofie in Ghana has taken the desperate step of giving part of his land to illegal sand miners, a lucrative practice driven by high construction demand since sand is used in concrete.

The cost is severe, however: the sand mining makes the land infertile.

Aware of the danger, Fofie said he had been left with little choice. He said annual cocoa bean yields has b...