The plant, which cost US$188 million to build, has capacity to produce 350,000 tons per annum of potash.
President Morales celebrated the plant as a triumph for his government's industrialization policy.
"This is a source of pride for Bolivia because this plant is 100% Bolivian owned and paid for with Bolivian money. This has never happened before," the head of state said.
The plant, said Morales, would make Bolivia the world's ninth largest potash producer and the third largest in South America.
Sales of potash to the country's farmers should recoup the investment within five years, the government said. But its ultimate aim is to begin extracting lithium from the brines under the Salar de Uyuni.
With three-times the surface area of Chile's Salar de Atacama, which produces around 40% of the world's lithium, the Salar de Uyuni is estimated to contain 9Mt of the mineral, according to the United States Geological Survey.
State-owned Yacimientos de Litio Bolivianos (YLB) is now advancing construction of plants with capacity to produce 15,000tpa of battery-grade lithium carbonate and 25,000tpa of lithium hydroxide from the end of the next year.
After work will begin on plants to turn the chemicals in lithium cathodes and finally batteries for which the government plans form a joint venture with Germany's ACI System.
"This industry will be a pillar of the economy in the medium term which will provide income, working and cutting-edge technology," predicted Luis Alberto Echazú, Bolivia's deputy minister for energy technologies.
