"The mulch insulates the soil, keeps weeds at bay, and protects the plants against extreme temperatures," explains Francis Mureithi, a tall farmer, as he scoops up manure from a compost pit.

Farmers in the region used to grow their crops using chemical fertilisers that were expensive and left behind chemical residue, Mureithi told the Thomson Reuters Foundation.

However, some are experimenting with organic farming as a cheaper and more drought-resistent way to grow crops ranging from nuts to coffee and maize.

Since 2010, the Kenya Organic Agriculture Network (KOAN) and experts from Kenya's Egerton University have been training rural communities on organic farming, as part of a project funded by macadamiafans GmbH, a German-Kenya company that promotes organic farming and new markets for Kenya.

The aim was to create a new sustainable market system around the nuts, from cultivating them to processing and exporting them.

Macadamia are good at tolerating drought, said Rhoda Jerop Birech, a professor from Egerton University, because "their leaves lose little water regardless of the temperature and sunshine".

As part of the effort, the farmers earn an ecological certification for their products – a process which takes three years and involves visits from field officers who check that the soil is free of chemicals and the nuts are of high quality.

Birech said over 2,000 farmers have now been trained. And John Konji, a field officer for macadamiafans, said nearly all of those who have stuck with the programme have gone on to win certification.

No middlemen

Mureithi, one of the first eight farmers to be trained in 2010, said macadamia farmers traditionally sold their produce to brokers, who would act as an intermediary between the farmers and nut processing companies. "But they were taking advantage of us and stealing money from us," he charged.

Now, instead of selling their produce to middlemen, the farmers have learned to process the nuts themselves, from drying to shelling them and sealing them in packaging.

The nuts are then shipped to Germany, where students from a partner school in Göttingen sell the produce in an attempt to learn about social entrepreneurship.

Farmers say the new methods of growing nuts have had big benefits for them.

"I used to lose 70 percent of my produce in times of drought, compared to only 20 percent now, thanks to the mulch that keeps the soil moist," said Stephen Karanja, one farmer.

Charles Mwangi, another farmer, said his harvest has tripled, to 3,000 kg of nuts a year, after changing his farming practices. He now sells his nuts at Ksh 100 (about $1) per kilo, compared to Ksh 20 previously, he said. "This has allowed me to not only feed my family but also send my three children to university."

Mary Wanja added that organic farming has allowed her to halve her farming costs by saving the money she used to spend on chemicals. "It also more healthy as consumers now eat produce that is chemical-free."

Anthony Ngondi, head of macadamiafans in Kenya, said the changes should help ensure farmers are more resilient in the face of more extreme weather associated with climate change. "Organic farming has given local communities a reliable source of income by ensuring their crops can withstand drought."

Source: Reporting by Caroline Wambui; editing by Zoe Tabary and Laurie Goering of the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, climate change, women's rights, trafficking and property rights. Visit: http://news.trust.org/climate

Photo: Farmers take part in training on organic farming techniques in macadamia production in Githure, in central Kenya. TRF/Caroline Wambui