Small changes, big results: increasing crop yields in Africa with micronutrients


Adding a few extra ingredients to fertiliser is a possible solution to increasing yields for main grains like maize in Sub-Saharan Africa, according to a recently published article.

Most crop farmers are used to enriching soil with fertilisers containing N, P and K (nitrogen, phosphorus and potassium) or so-called macronutriets, to enhance crop health and ultimately increase yields.

But a recently published article on crop nutrition in Sub-Saharan Africa (SSA) found that applying secondary nutrients, like sulphur (S), and micronutrients like copper, molybdenum, iron and boron – in addition to normal fertiliser – could increase grain yields with up to 25%.

“Coupling the ongoing efforts towards the African green revolution with the supply of S and micronutrients in most fertilisers, is vital for enhanced agricultural productivity.”

The topic is well-studied globally, but according to the paper there are still various knowledge gaps in Africa. The paper recommends that more research is done to look into the conditions surrounding application, as well as the difference between and within different crops.

“Addressing such secondary and micronutrient deficiencies is critical to resolving the recurrent food insecurity challenge facing SSA that is heightened by a burgeoning population and climate change.”


The scientists from Kenya and Zambia conducted a meta-analysis on data from field trials to analyse the change in yields with sulphur and micronutrient application. Their research focused on maize, rice, wheat, sorghum, cowpea and soybean because of their data availability and the importance of the crops in SSA.

The researchers found varying results in the yield increases for different grains. Maize, wheat and rice showed positive yield responses to applied S or micronutrients. A lower response was observed in sorghum, cowpea and soybean.

“However there are strong indications from some studies of the effects of the deficiencies in secondary nutrients and micronutrients limiting crop productivity in SSA, especially under continuous cropping without crop replenishment.”


The researchers, however, noted that the application of the secondary and micronutrients should be calculated carefully, since over-application resulted in negative growth results.

“Understanding the conditions under which different responses occur and designing fertiliser solutions to address the limitations, are critical in maintaining and or increasing crop productivity.”


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