In Africa, agriculture employs about two-thirds of the continent's workforce and contributes an average of 30 to 60 percent of countries’ Gross Domestic Product (GDP).
However, the soils are subjected to severe hardships (massive export of nutrients by crops, exposure of soils during harvesting, inadequate use of chemical fertilizers and pesticides, heavy erosion, monocultures, etc.). They are not as healthy and productive as they should be. Rather, these unsustainable agricultural practices lead to the degradation of agricultural land with 56% being subject to acidity.
In Liberia, more than 70 percent of people rely on agriculture for their livelihoods – the acidity found in 75 percent of soil diminishes the capacity to improve food security and increase efficiency in agricultural value chains, putting farmer livelihoods and the health of the national economy at risk.
It is now essential to rehabilitate these acidic soils in order to improve the health of agricultural land. This rehabilitation is also necessary for developing agricultural systems that are resilient to climate change.
Few farmers, especially smallholders, know the state of their soil's fertility, especially if acidity is present. Yet, small-scale tests are simple to carry out: the pH paper strips give the farmer instant feedback. Once these tests have been carried out, applying agricultural lime and adopting good agricultural practices have proven to be very effective solutions to fighting soil acidity, with convincing results.
Liming, developed in Europe since antiquity, is beginning to generate real interest in Africa. Ethiopia, Kenya, Tanzania, and Rwanda have launched strategic plans for acid soil rehabilitation/restoration, which are supported by substantial public investment. These are often accompanied by growing - albeit still modest - private investment from the lime industry.
This manual is intended for agricultural technicians, and anyone interested in soil acidity remediation, as well as in the testing and application of agricultural lime.
