Why maize yields will decline despite rains

Wednesday March 16 2011

By GATONYE GATHURA [email protected]

Maize production will continue to decline even with good rains, according to scientists.

They warn that the crop is not as heat tolerant as previously thought, with harvests showing a steady decline since 1999.

The scientists analysed climate data and maize output from a research site in Kiboko in Eastern Province between 1999 and 2007 and concluded that output would continue to decline, with some areas experiencing total crop failure.

Kiboko was only one of the more than 20,000 maize research sites in sub-Saharan Africa where researchers from the International Maize and Wheat Improvement Centre and Stanford University carried out studies concluding that maize was a crop in peril.

The study, to be published later this week in journal Nature Climate Change, says climate warming of one degree Celsius could result into a production decline of 20 per cent, with entire regions becoming totally unsuitable for the crop.

According to the Environment ministry, Kenya has been experiencing rising temperatures since the 1960s.

The Agriculture ministry is promoting alternative crops to enhance food security.

It has distributed planting material for sweet potatoes, cassava, pigeon peas, common beans, cow peas, green grams, dolichos, lablab, chick peas, sorghum and millet.

“The changes being blamed on global warming are passing a message to farmers that they have no option but to discard this attitude that only maize need to be grown come rain or sunshine,” says Dr Charles Kariuki, the director of Kenya Agricultural Research Institute’s Katumani Centre.

The study also rules out water as the only determinant in maize production. “The pronounced effect of heat on maize was surprising because we assumed maize to be among the more heat-tolerant crops,” said Marianne Banziger, co-author of the study and deputy director-general for research at the maize centre.

The researchers demonstrate that when this “normal” climate change is accompanied with drought, which is expected to happen more frequently in Kenya, it will make it almost impossible to meet the country’s maize