Africa will be self-sufficient in fertiliser within 40 months, Nigerian billionaire Aliko Dangote said on Friday, on the basis of a planned expansion of his $2.5 billion plant on the outskirts of Lagos.

Africa currently imports over 6 million metric tons of fertiliser annually as it struggles to produce enough food in often challenging growing conditions.

The benefits of increasing domestic production would include reduced foreign exchange expenditure, which has been a major economic burden in Nigeria because of the weakness of the local currency.

"In the next 40 months, Africa will not import fertiliser from anywhere. We have a very aggressive trajectory right now. We want to put Dangote to be the highest producer of urea, bigger and higher than Qatar - give me 40 months," Dangote said at the annual Afreximbank meeting in Abuja.

Dangote runs Africa's largest granulated urea complex, which has annual capacity of 3 million tons, 37% of which it exports to the United States. It will need to double current output to achieve his ambition. Dangote has said he is not worried about the impact of Trump tariffs.

Analysts say the market outlook for fertiliser is bullish, but there are also challenges and the kind of expansion Dangote seeks requires infrastructure to be built.

"Any new fertiliser plant or expansion project faces cost overrun risks to the producer," Seth Goldstein, senior equity analyst at Morningstar Research, said.

Mikolah Judson, an analyst at global risk consultancy, Control Risk, cited the need for "transport infrastructure and port capacity," saying "bottlenecks routinely delay various import and export projects in Nigeria".

Dangote has a track record for delivering big projects. He also owns the Dangote Petroleum Refinery, Africa's largest, although its launch was repeatedly delayed and it exceeded its initial budget.

He has said he intends to list the 650,000 barrels-per-day refinery next year and on Friday he also confirmed plans to list his fertiliser plant on the local stock exchange this year.

(Reporting by Isaac Anyaogu; editing by Barbara Lewis)