Fertilizer nutrient imbalance to limit food production in Africa

A press release from the International Institute for Applied Systems Analysis: A growing imbalance between phosphorus and nitrogen fertilizer use in Africa could lead to crop yield reductions of nearly 30% by 2050, according to a new study from researchers at the International Institute for Applied Systems Analysis (IIASA).

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.

“This research shows that the imbalance between nitrogen and phosphorus applications has the potential to further limit food production for a growing population in Africa” says Marijn van der Velde, a researcher now at the Joint Research Centre of the European Commission, who led the study while working at IIASA.

...“Farmers with limited money are more likely to buy and have access to cheaper nitrogen-based fertilizers,” says van der Velde. “While this might work in the short term, in the longer term it has a negative effect on crop growth as soil nutrients become more imbalanced.”

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....

An electron shell diagram of phosphorus, created by Pumbaa (original work by Greg Robson), Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.0 UK: England & Wales license