New research from a national survey of Nigerian farmland shows soil organic carbon is the strongest predictor of plant-available phosphorus, ahead of soil texture, iron and aluminum oxides, and acidity. Researchers analyzed 554 samples from 390 sites across seven agroecological zones and found organic matter helps release phosphorus, but the effect plateaus and is modified by clay and oxide content. That helps explain why fertilizer recommendations that work in one Nigerian field can fail in another. The study suggests soil management should match the local constraint. Sandy, low-carbon soils in the drier north need organic matter to build nutrient retention, while clay-rich, oxide-heavy, or more acidic soils need organic inputs paired with appropriate phosphorus fertilization and, where acidity is high, liming. For anyone tracking soil carbon, regenerative agriculture, or food security in sub-Saharan Africa, this is a useful evidence base for targeting interventions instead of applying a one-size-fits-all approach.
