Mele Kyari, general manager of NNPC, which runs joint venture companies with Shell and TotalEnergies Nigeria said during the signing ceremony that Dangote's plants supplied 65% of Nigeria's domestic fertiliser requirements.

"It's government's drive to ensure that we become self sufficient in the production of fertiliser in our country, and specifically for this year, it's zero import of fertiliser into our country," Kyari said.

Nigeria's central bank bars the use of its foreign exchange for fertiliser imports as part of controls aimed at boosting domestic production.

Aliko Dangote, CEO of Dangote Group and Africa's richest man, said the new gas supply deal would enable his company to generate more than $1.8 billion in export earnings.

"Apart from Egypt, no ... other African country now has our capacity. We will meet the domestic market and then we will be able to export at least $1.8 billion in terms of foreign exchange coming into the country," he said.

According to the World Bank, Nigeria consumed around 20 kg of fertiliser per hectare of arable land in 2018, compared with 73 kg in South Africa and 393 kg in China.

(Reporting by Camillus Eboh and MacDonald Dzirutwe, Editing by Cynthia Osterman)