Sub-Saharan Africa's second biggest economy lures agricultural investors as it seeks to diversify its hydrocarbon dependent economy

Nigeria has attracted billions of dollars of inflows in the agriculture sector over the last two years, as it looks to diversify its economy away from oil and gas dependence and to meet food security targets. It is now seeking investors for new agricultural processing zones, the country's minister of agriculture Akinwumi Adesina says.

"In the last 18 months we've been able to generate $8bn of private sector investment commitments and as of this month we have letters of intent from 28 local and international companies for $3.3bn," he told This is Africa as he prepared to attend a summit on hunger and nutrition in London last weekend.

Nigeria has unveiled six new 'Staple Crop Processing Zones' offering land, infrastructure and tax incentives to private investors, and will add a further eight before 2015.

Amongst the groups targeting Nigeria is Cargill, the world's biggest agricultural trader by volume, which is investing an undisclosed sum in the Kogi state zone. It will focus on the processing of starch and sweeteners from local cassava.

Unilever, the consumer goods giant, also intends to set up a plant to process hundreds of thousands of tonnes of cassava roots into sorbitol, a key component in toothpaste. "We are looking at Nigeria because we have a factory there that produces toothpaste and a growing market, but we currently import sorbitol from China to make it," a spokesperson for the company confirmed. "Our intention is to produce sorbitol that is globally competitive not simply an import substitute for Chinese sorbitol."

Other players include Aliko Dangote, Africa's richest man, who is spending around $2bn on what will be the continent's biggest fertiliser plant. In the palm oil sector, the Industrial Development Group - a company engaged in the startup of industrial enterprises in developing markets - and PZ Wilmar - a joint venture between the London-listed PZ Cussons and Singapore's Wilmar International - are plugging a cumulative $1bn into separate production and processing programmes.

Separately, the seed company Syngenta will set up an office in Nigeria in June.

In the 1960s, agriculture contributed over 60 percent of Nigeria's GDP and 70 percent of exports, but that dominance evaporated with the oil boom of the 1970s and the country now spends around $11bn a year on food imports. The processing zones are seen as a way of developing much-needed value-added businesses.

"Currently, we are number two in the world in citrus production after China, but we don't produce orange juice. We are the largest in Africa in the production of pineapples and tomatoes, but we don't process them. We are allowing our products to rot away because we are not processing them," Adesina explains. "Agriculture is not a development activity, it is a business, so we must add value to every single thing that we produce."