Soil Organic Carbon Sequestration in Finger Millet Production in Sub-Saharan Africa: A Review of Concepts and Practices

Abstract

Soil has the capacity to sequester about 50-66% of the 42-78 Giga tons of carbon lost per year. However, the capacity of the soil to sequester carbon is dependent on soil texture and structure, rainfall, temperature, farming systems, and soil management practices. Management practices to enhance soil carbon sequestration include; cover cropping, nutrient management, woodland regeneration, no-till farming, manure, and sludge application, water conservation, and harvesting, efficient irrigation, and agroforestry, among others. These practices have however been applied in un-integrated manner, this has led to continuous loss of soil carbon; consequently, there has been a decline in crop yield especially cereals due to climate- change, soil degradation, pest, and disease burden, among other factors. Yet an increase in soil carbon by one in a degraded soil could increase cereal yield by up to 40 kg ha-1, for example, increase wheat yield by up to 20-40 kg ha-1 and Maize up to 10-20 kg ha-1 as well as reducing fossil fuel emission by 0.4-1.2 Giga tons of carbon per year. This review paper, therefore, looks at current ways of sequestering carbon and how these approaches can be improved and integrated to enhance soil carbon sequestration in cereal-legume cropping systems. There is a need to increase the production of cereals due to the increasing demand for cereals in sub-Saharan Africa and it is projected that, by 2050, the demand is expected to triple due to global population increase which is expected to outmatch production due to low soil carbon sequestration and soil fertility.