OpenLandContracts.org, based at Columbia University in New York and backed by the World Bank, lists details of 69 deals so far involving palm oil plantations, sugar cane, biofuels, soybeans, tea and other crops in eight countries.

Organizers expect to have some 100 entries by year's end.

The database could lead more companies and countries to make the details of land deals public, said Kaitlin Cordes, head of land and agriculture at Columbia's Center on Sustainable Investment.

"There is such a lack of transparency around these deals," Cordes told the Thomson Reuters Foundation. "Making contracts transparent can help individuals, communities and civil society monitor whether governments and investors are fulfilling their responsibilities."

Large land deals, which can pit international investors against small-scale farmers, can be controversial when signed in secret without local input.

If firms do not have to disclose details of their deals, they have less incentive to incorporate social investments such as environmental management, training and jobs for local people, she said.

The site, which launched earlier this month, so far shows deals in Liberia, Ethiopia, Democratic Republic of Congo, Sierra Leone, Cambodia, Cameroon, South Sudan and East Timor.

Reporting by Chris Arsenault, Editing by Ellen Wulfhorst of the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking, corruption and climate change. Visit: www.trust.org