World scientists are meeting in the Kenyan capital Nairobi on Tuesday to discuss Africa's food security challenges and how best to manage the continent's soils for increased food and crop productivity.

Participants at a five-day Integrated Soil Fertility Management Solution (ISFM) conference are expected to tackle fertility depletion as one of the major constraints to food security and income generation in sub-Saharan Africa.

The participants said nutrient depleted soils and poor soil fertility are major obstacles that farmers continuously face every day in Africa.

"In addition, the farmers lack access to fertilizers and improved seeds. This happens against the backdrop of a diverse number of solutions and resources applied by a wide range of institutions, in efforts that are directed at solving the problems, " they said.

"This conference assembles the strengths of several organizations and collaborative research projects committed to designing, funding and delivering practical solutions to food insecurity and agriculture resource degradation in Sub-Saharan Africa," said Dr. Kenton Dashiell the Co-Chair of the conference.

According to scientist Dashiell, over the next 40 years the population of sub-Saharan Africa is set to increase by 700 million inhabitants.

This translates into a massive increase in the need for food, feed, fiber and fuel, in a region where many countries already import significant amounts of food.

Whilst it is likely that there will continue to be some further expansion in the area cultivated, there are many competing claims on land for urban development and for wilderness. Given current crop yield levels there is great potential to increase agricultural production through intensification of production on land already under cultivation.

Dr. Saidou Koala, the co-chair of the conference, said the significance of the week-long conference is underpinned by the fact that it offers the platform through which the African continent embarks its exploration of options for sustainable intensification and diversification of farming systems.

The meeting will further seek to incorporate scientific knowledge with practical understanding of how biological, organic and mineral fertilizers are best integrated in the management of agricultural soils and crops by small-scale farmers in Africa.

"A particular focus of this conference deals with the comparison and scaling up of candidate breakthrough technologies, monitoring and evaluation of their impacts within rural settings and along agricultural value chains and strategies that increase capacities in Integrated Soil Fertility Management," added Koala.

ISFM conference theme is guided by the 2006 African heads of states meeting in Abuja Nigeria agreement that each country in sub- Saharan Africa works towards making their farmers use at least 50 kg of fertilizers from the then average of 8 kg per hectare, in a bid address the food shortages on the continent and make the continent self-sufficient in food production.

Among the topics being discussed are break-through technologies including the use of soil biota to curb crop diseases, use of soil biota to increase soil fertility, use of integrated soil fertility management, including the use of mineral fertilizers, use of organic fertilizers, use of improved higher yielding seeds, use of legumes as green manures among others.

Also being discussed are the roles of marketing and markets in stimulating food production, use of ICT to reach millions of farmers and policy instruments to radically change the continents food production scenario and thereby bridge food security gaps.

"We will discuss how best to manage the soils of Africa for increased food and crop productivity. Some of the papers to be presented will benchmark the current status of fertilizer use while others will provide information on solutions while others will discuss constraints," quipped Dr. Peter Okoth who is the scientist responsible for communication in the Conference Organizing Committee.

With the ever growing population on the continent, farmers continue to grow crops on the same land year after year. Under such continuous use, soil fertility declines if nutrients mined from the soil in the crop products are not returned to the soil.

To deal with this problem mineral fertilizers are essential. But as fertilizers are more expensive in Africa than anywhere else, most farmers use none at all. In response, many countries have subsidized fertilizers, yet often ignoring supportive agricultural practices, institutions and policies.

The scientists say increasing the productivity of smallholder farmers requires a good understanding of yield gaps (that is differences between actual, obtainable, potential yield under prevailing economic conditions) as well as bio-physical and socio- economic factors constraints that hinder the closing of exploitable gaps.

African farmers therefore need improved seeds, fertilizers and better technologies to prevent further degradation of their lands and enable them to maximize output from their farms. This will in turn curb food insecurity in the continent.

Other interventions include - advancing plant-microbe interactions in crop nutrition, enhancing biological nitrogen fixation in African farming systems and building capacity in Integrated Soil Fertility Management.

Other interventions include breakthroughs in inoculation, exploring options for sustainable intensification and diversification of farming systems, soil biota in ecosystems management, bio-prospecting tools, strain selection and delivery, identifying bottlenecks and opportunities for implementation of integrated soil fertility management.

According to Okoth, a Policy Discussion Forum will also be part of the conference where policy makers from different countries and scientists will engage in a Panel discussion to suggest policy recommendations that are aimed at providing some suggested direction on how the African governments as well as Donors could contribute to alleviating the problem of food on the continent.

However, experts said improving the natural resource base without addressing issues of health, nutrition and income generation is often the reason for a lack of adoption of improved technologies and other farming practices.