Neglecting the health of Africa's soil will lock the continent into a cycle of food insecurity for generations to come, a report has warned.
The publication by the Montpellier Panel said the problem needed to be given a higher priority by aid donors.
It added that soil degradation was also hampering economic development, costing the continent's farmers billions of dollars in lost income.
The study has been published ahead of the 2015 international year of soils.
The Montpellier Panel - made up of agricultural, trade and ecology experts from Europe and Africa - warned that land degradation reduced soil fertility, leading to lower crop yields and increased greenhouse gas emissions.
"In Africa, the impacts are substantial where 65% of arable land, 30% of grazing land and 20% of forests are already damaged," it observed.
Panel chairman Sir Prof Gordon Conway, from Imperial College London, told BBC News: "We spend a lot of time talking about crops and we spend a lot of time talking about livestock. We have big debates about all kinds of agriculture, yet we tend to ignore that it all depends on soils."
He added that recent measurements had shown that soil degradation levels across the continent were very high.
"Serious land degradation [accounts for] about a quarter of land area of sub-Saharan Africa - it is a vast area," he said.
"There are about 180 million people who are living on land that is in some way or another degraded. It is really very severe."
The problem threatened food production in a region that was already experiencing very low crop yields, he explained.
"The average yield in sub-Saharan Africa is about one tonne per hectare. In India, it is about two-and-a-half tonnes, while in China it is more than three tonnes per hectare.
"So in Africa, we have the combination of land degradation, poor yields and a growing population."
Sir Gordon described the issue as a "crisis of land degradation and soil management", adding: "We have got to do something about it".
The panel made a number of recommendations, including:
- Strengthening political support for land management
- Increase financial support for investment in land and soil management
- Attribute a value to land degradation
- Create incentives, especially sure land rights
- Build on existing knowledge and resources
The report said the panel's members believed that soil was the "cornerstone of food security and agricultural development and its care, restoration, enhancement and conservation should intuitively become a major global priority".
Sir Gordon added: "Africa already imports US $40bn worth of food each year, it is an enormous amount. If we do not produce more food in Africa, that will get worse and worse, and the continent will suffer as a result.
"Secondly, if we do not pay attention to land degradation in Africa then the land itself will continue to degrade and that will further reduce the yields we are getting at the moment.
"We know what you have to do to improve the quality of soil, but the big challenge is providing the funds and making sure that there are incentives for farmers.
"Farmers will not invest in their land unless they have land tenure. In many cases, they cannot afford to invest in their land so there needs to be public money available.
"In South-East Asia, the great irrigation schemes that have provided much of the food security in the region were publicly funded."