Underuse of phosphorus-based fertilizers in Africa currently contributes to a growing yield gap — the difference between how much crops could produce in ideal circumstances compared to actual yields. This phosphorus-specific yield gap currently lies at around 10% for subsistence farmers, but will grow to 27% by 2050 if current trends continue, according to a study published today in the journal Global Change Biology.
As farmers use fertilizers for their crops, nutrients such as nitrogen and phosphorus build up in the soil, providing a reserve of nutrients that plants need to grow. But fertilizer use remains very low in Africa, and to increase crop production, it is widely recognized that farmers must increase their fertilizer use. And while nitrogen-based fertilizer usage has begun to increase in Africa in the last 10 years, the application of phosphorus to cropland has not kept pace, leading to a growing imbalance between nitrogen and phosphorus levels in soil. The new study shows that increases in nitrogen and phosphorus inputs must happen in a way that provides crops with the balanced nutrient input they need.