Fertiliser can offset heat for African farmers
[NAIROBI] African smallholders in dry areas can overcome climate change and even double crop yields if they invest in fertiliser use and harvest rainwater, researchers have found.
Farmers in arid and semi-arid areas usually protect themselves from climate-related losses by investing as little as possible in farm inputs such as fertilisers.
But in doing so they fail to grab opportunities for large yields in the good seasons, researchers from the International Crop Research Institute for Semi-Arid Tropics (ICRISAT) have found.
They entered parameters for crop growth — such as rainfall, soil type and crop type in a particular region — into a computer program, the Agricultural Production System Stimulator, to model the impact of increased temperatures on crop production across Africa.
They found that climate change need not negatively affect crop production. Provided rainfall is unaffected, farmers who effectively use fertilisers and use mulch to trap water in the soil for longer could double yields, even with temperatures increases of up to three degrees Celsius.
The model for Makindu in eastern Kenya found that if farmers used waste from maize crops as a mulch and used a technique called tied ridging, in which soil is sculpted to direct water towards crops, higher crop yields were possible at three degrees Celsius.
ICRISAT suggests farmers use approximately 20 kilograms of nitrogen per hectare — compared to the current average of five kilograms — and rotate cash crops with leguminous crops such as groundnuts and beans.
"[The model] is a powerful tool in determining how climate change will influence crops' growth and yield," said Karuturi Rao, a senior researcher at ICRISAT.
Peter Cooper, ICRISAT's principal scientist for East and Southern Africa, said the research shows that climate change does not have to be a disaster for a farmer who is prepared for it. Using these technologies, African farmers can still prosper, he said.
Cooper urged policymakers in Africa to take food production more seriously and prioritise agriculture — putting policies in place to ensure reduced fertiliser costs, for example.
"More should be done to support small-scale farmers so that they can improve their crop yields. It is a good thing that governments are now beginning to cast an eye on agriculture, but they should do more — what they are doing is not enough."