* Farmers bringing in faster-growing, drought-resistant crops
* More need to store water, switch to hardy crops
* Africa specially vulnerable to climate change
By Alister Doyle
OSLO, Sept 7 (Reuters) - African farmers are finding new ways to cope with droughts, erosion and other ravages of climate change but need to develop even more techniques to thrive in an increasingly uncertain environment, scientists said on Friday.
Smallholders have started to plant more drought-resistant and faster-growing crops to keep the harvests coming in, according to a survey of 700 households in Kenya, Ethiopia, Uganda and Tanzania.
"The good news is that a lot of farmers are making changes," said Patti Kristjanson, who heads a programme on climate change, agriculture and food security at the World Agroforestry Centre in Nairobi and led the study.
"So it's not all doom and gloom ... but much more needs to be done," she told Reuters.
Farmers, backed by researchers and international donors, needed to find better ways to store rain water, increase the use of manure and bring in hardier crops like sweet potatoes, she said.
In the past decade, 55 percent of households surveyed said they had taken up faster-growing crop varieties, mainly of maize, and 56 percent had adopted at least one drought-tolerant variety, according to the findings in the journal Food Security.
Fifty percent of the households were planting trees on their farms - helping to combat erosion, increase water and soil quality and bring in new crops like nuts.
Half of the farmers had introduced inter-cropping - planting alternate rows of, for instance of beans and maize, in the same field and then swapping the rows next season. Beans fix nitrogen in the soil, helping reduce the need for fertilisers.
But Friday's study found just a quarter of farmers were using manure or compost - avoiding the use of more expensive fertilisers. And only 10 percent were storing water, it added.
The study said that global warming, leading to erosion, less reliable rainfall and changes in the length of growing seasons, was adding to other stresses for farmers worldwide such as price spikes and a rising population.
Kristjanson said the study showed encouraging signs of many farmers' willingness to adapt.
But faster change may be needed because Africa is especially vulnerable to climate change, according to the U.N. panel of climate scientists which blames heat-trapping emissions of greenhouse gases from burning fossil fuels.
In Africa, up to 220 million people could be exposed to greater stress on water supplies by 2020 and yields from rain-fed agriculture in some countries could be cut by up to 50 percent by 2020, according to a 2007 U.N. report. (Reporting By Alister Doyle; Editing by Andrew Heavens)
African Farmers Face Climate Change Threats, More Needs To Be Done, Study Says