BULAKAN, Bulacan—In the waning heat of the day, 57-year-old Reneboy Ybañez would begin raking salt from clay-lined salt ponds in Barangay San Nicolas in Bulakan town. By 3 p. m., most of the seawater in the ponds had evaporated, leaving salt crystals that he and the other workers would harvest. Reneboy and his wife May,...