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How understanding microbes can help farmers manage Africa’s soil crisis

Tens of millions of smallholder farmers across sub-Saharan Africa have a stake in improving the health of the soil their cattle graze on. Reuters/Goran Tomasevic

To harness the potential of soil microbes Africa must move quickly. As soil degrades, so too does microbial life.

Understanding the microbial diversity of Africa’s soils is important for another reason as well. At least some portion of this diversity is indigenous to particular soils, crops and ecosystems developed over thousands of years of farming.

At a time when multinational corporations are investing to identify, develop and patent soil microbial uses and inventions, Africa needs to understand the value of microbes.

The commercial value of its diversity should be realised.

At the same time, many of the agronomic products developed are based on soil microbes. This will benefit farmers elsewhere who face similar challenges, whether arid soils or crop diseases.

Root-based evidence

At an Auburn University laboratory, we have demonstrated that soil microbes can help corn and cotton plants withstand insect damage and water stress. Research has been directed at basic and applied aspects of using beneficial bacteria as microbial innoculants to promote plant growth and provide biological disease control. This enables plants to grow better, with bigger roots.

Research points to the possibilities:

  • In Mexico, results from a three-year field trial showed that application of beneficial microbes could help restore eroded soils in the southern Sonoran desert.

  • In Egypt, researchers showed that enriched populations of beneficial microbes enable pepper plants to survive and grow in the desert.

  • In Colombia, farmers have used soil microbes to increase the yield of cassava plants by 20%. And in India, microbes were used to enhance drought tolerance in rice.

Creative solutions

Africa’s soil crisis calls for quick and creative action. In addition to a citizen soil knowledge initiative, we need to use all the techniques already available to protect and restore soil, particularly through applying integrated soil fertility management.

This is the approach widely promoted by organisations such as the Alliance for a Green Revolution in Africa.

The alliance invests in agriculture as a way in which to help tackle poverty. It combines farming methods and materials available to farmers to improve soil health, whether manure, fertilisers or crop residue left in the field.

Promotion of integrated soil fertility management can go hand in hand with engaging farmers in citizen science networks. It will connect them to agricultural universities, research institutions and agricultural enterprises.

Citizen science enlists people who care about the issue and involves them in the process of inquiry and discovery of new knowledge. The National Aeronautics and Space Administration (NASA), for example, is using citizen science to map global soil moisture.

Citizens collect, weigh, dry, and reweigh soil samples to determine soil moisture content. They add this data to a central information hub on the internet. Participants get feedback about the quality of their soils and how best to care for them.

There are tens of millions of smallholder farmers across sub-Saharan Africa. They all have a stake in soil health.

Given the opportunity through a citizen science initiative, they could revolutionise understanding of African soils. This would increase the continent’s ability to use the soil microbes that are essential for agriculture and life.

Sowing the citizen science seeds

Farmers must be encouraged and supported through a broad-based citizen science initiative. NASA’s work is a good example of citizen science having the desired effect.

Such a campaign on African farms must be coordinated with agricultural universities, research institutes and agricultural enterprises.

A citizen science initiative to identify and analyse soil microbes could combine the use of simple field lab testing of soils and mailing duplicate soil samples to national or regional laboratories for deeper analysis.

Clearly, much would need to be hammered out for the network, including the designation of laboratories; staffing and funding; principles for the sharing and use of data; and communication of findings back and forth between citizens and scientists.

But this is crucial. Africa’s future food security depends on how we protect and restore its soils today. The problem is so extensive that doing so will take every tool at our disposal, and the support of every ally.

As an African soil scientist, I know that there is an army of biological allies in the soil itself – soil microbes. There are more microbes in teaspoon of soil than there are people on earth. They are all constantly at work.

Microbes enable soils to cycle nutrients and water and to maintain a healthy structure. They also promote plant growth, even under stressful conditions. Soil microbes offer new tools for the revitalisation of degraded soils, and for strengthening the resilience of crops subjected to increasing levels of environmental and climatic stress, diseases and pests.

Soil is the base of our food, income and economy.

But across 65% of African farmland, soil is in trouble. Most of it is depleted. What gives the soil life, threatens its very existence. Soil lacks life-giving nutrients, organic matter and rich microbial communities.

The solution should start with farmers. A comprehensive knowledge of soils, especially their little-known but crucial microbial life, must be developed.

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