On the hillside where Cecilia Mwai Kimanzi farms, bean plants nudge their way up through the moist, reddish-brown soil. In some regions of Kenya and many other African countries, rich topsoil like this is in short supply, having been washed away by the rains.
But things are different here. Most farms are terraced. Runoff soil and water, trapped by the ridges, nourishes the crops. As a result, bean and corn production has more than doubled on terraced farms in Kenya.
``When the farm was not being terraced, I was getting less crops,'' Mrs. Kimanzi said recently while supervising several women and children weeding the farm she and her husband own here. ``But now there is progress,'' she says.
The word on terracing has gotten around, and now more than half the 1.5 million farms in Kenya that could benefit from terraces have them, thanks to an all-out Kenyan effort and international aid.
Kenya is leading efforts in Africa to reduce soil erosion in semi-arid farming regions. ``Successes in soil conservation are few and far between,'' writes Paul Harrison in his recent book, The Greening of Africa. ``Perhaps the most outstanding program in Africa has been Kenya's.''
The keys to this success, according to Kenyan and international experts, is twofold: simple, cheap methods, that can be carried out primarily by the farmers using hand tools; and strong government promotion of soil conservation efforts.
Literally hundreds of thousands of Kenyan farmers have dug terraces on their hilly fields, using hand tools provided by foreign assistance. Those who could afford it, like the Kimanzies, hired paid labor for the strenuous work. But many other farmers pooled their efforts, working together to dig the terraces.
``We found you can't work alone,'' says Minza Mwikyawikya, an elderly Kenyan still farming near here. He helped form a group that has dug terraces, built low dams to trap drinking water, and planted trees. ``We found it's a good thing to unite together.''
All this effort comes of necessity, says Maurcie Mbegera, a Kenyan government soil conservation official. ``The problem is, the high potential [growth] areas supporting the rest of Kenya in food production are getting over-pressed with population,'' he says. Farmers are spreading out to farm and pasture lands once considered not good enough for farming. In many regions, they are moving onto hilly slopes susceptible to severe erosion.
But Kenyan President Daniel arap Moi has made fighting soil erosion a priority. He personally participates from time to time in conservation projects. And he has set up a presidential commission to coordinate work on behalf of forestation and soil conservation.
Kenyan extension agents fan out across the country to teach farmers to teach other farmers terracing techniques, taking their cue from President Moi and local politicians.
One Sunday, even church leaders were ``preaching in the church on soil conservation,'' says Arne Eriksson, a soil conservation specialist in Kenya with the Swedish International Development Authority (SIDA).
Terracing is not new to Kenya. The British colonial administration ``forced'' farmers to build terraces, according to soil conservation experts here.
After independence in 1963, terracing was largely abandoned. The practice had a bad name by being so closely associated with forced labor and colonial rule. But in the early 1970's, Kenya sought the help of the Swedish government in reviving the practise - this time without force.
Beginning in 1974, SIDA began assisting Kenya on this - and still does. Under a grant program, SIDA today provides experts and about $2.3 million a year. The US also has provided some assistance.
One of the techniques the Swedes and Kenyans developed is a terrace called fanya-juu, (Swahili for ``do up.'') It is based on methods once used by the Kamba people, who live in this region about two hours southeast of Nairobi, the capital.
A trench is dug along the contour of the hillside. The soil and rocks from the trench are thrown on the uphill side of the trench, forming a ridge. Gradually, the trapped soil tends to level off the terrace, even as it provides added nutrients and moisture to crops.
The ridge can be planted in grass to be hand cut for cattle. Even the trench can be used, for planting banana or some other fruit tree, which also serves to hold topsoil.
Terraces are most effectively used as part of a package of improved farming techniques, says Leroy Scherer, an American specialist who has trained farmers in this area in soil conservation. Other techniques, says Mr. Scherer, include crop rotation and planting legumes and some trees in fields, which deposit nitrogen (a natural fertilizer) into the soil.