Solomon, Dawit and Lehmann, Johannes and Fraser, James Angus and Leach, Melissa and Amanor, Kojo and Frausin Bustamante, Victoria and Kristiansen, Søren and Millimouno, Dominique and Fairhead, James (2016) Indigenous African soil enrichment as climate-smart sustainable agriculture alternative. Frontiers in Ecology and the Environment, 14 (2). pp. 71-76. ISSN 1540-9295
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Abstract
We report on an ancient-yet-extant indigenous soil management system in West Africa wherein targeted waste deposition transforms highly-weathered, nutrient- and carbon-poor tropical soils into enduringly fertile, carbon-rich black soils. These “African Dark Earths (AfDE)”, store 200-300% more organic carbon with 2-26 times greater pyrogenic carbon (PyC) that persists much longer in soil than other organic carbon, and therefore important for long-term soil fertility and carbon storage. Compared to strongly acidic (pH 4.3-5.3) adjacent soils (AS), AfDE exhibit higher pH (5.6-6.4) ideal for plant growth, 1.4-3.6 times higher plant nutrient retention and exchange capacity, and 1.3-2.2 and 5-270 times more plant-available nitrogen and phosphorus, respectively. Despite limited areas, AfDE make disproportionately high contributions (24%) to total farm household income. 14C radiocarbon ages of pyrogenic carbon (PyC) indicate recent development (115-692 years BP). AfDE are an appropriate “climate-smart” agricultural alternative to conventional agriculture to tackle the “trilemma of soil degradation and food security and climate change challenges” in resource-poor, highly food-insecure regions of the world.