This Is What a Climate-smart Farm Looks Like 

How One Kenyan Farmer Went From ‘Nothing’ to the Envy of the Neighborhood

Purity Gacaga’s small dairy farm in Embu, Kenya, is a model of climate change adaptation. (Tim McDonnell)
Purity Gacaga’s small dairy farm in Embu, Kenya, is a model of climate change adaptation. All photos by Tim McDonnell.

The highway from Nairobi to Purity Gacaga’s dairy farm runs through the croplands of central Kenya: hundreds of square miles of maize and vegetables, interrupted halfway along by the country’s largest rice plantation sprawling toward the horizon like a glassy green sea. The rice is industrially irrigated, hence the green; in contrast, the maize and vegetable plots are rainfed, and with this year’s rainy season weeks late, the hills are brown, dusty, and denuded.

The highway leads to Embu, a hub of a half-million farmers and traders, where the produce of this region is gathered to be sent south to Nairobi or north to the pastoral drylands. Purity’s farm is a bumpy 15-minute drive out of town and, compared to the farms leading up to it, is scarcely recognizable as a farm. It looks more like a miniature rain forest: four acres of dense trees and shrubs nestled in a valley that in the early morning captures a low-slung mist. It’s only when you get closer, under the tree cover, that you see the dazzling array of tomatoes, coffee, kale, and napier grass, and the hand-built corral that houses three cows and a motley herd of goats.

Purity’s homestead is an anomaly that emerged over the last few decades through a combination of luck, foresight, scientific curiosity, and a willingness to gamble on experimental approaches to farming. Once as barren and degraded as the farms alongside the Nairobi highway, it’s now the highly productive envy of the neighborhood. It’s also living proof of the efficacy of agroforestry: the strategic use of trees on farms to improve soil health and insulate crops from drought. The practice has lingered for years outside the mainstream of Kenyan agriculture, but some scientists see it as a low-tech, low-cost, readily available weapon for farmers against climate change.

Temperatures in Kenya are steadily climbing, up nearly 2 degrees Fahrenheit since the 1960s on average. And while total rainfall has increased marginally during that period, the distribution is increasingly unpredictable—mistimed rainy seasons and stretches of drought punctuated by downpours. With less than one percent of the country’s cropland under irrigation, the brown fields en route to Embu are now the rule, not the exception.

That’s a bad sign given that one-fifth of the Kenyan population is already considered food insecure by the United Nations Food and Agriculture Organization, and the population is growing at a rate twice the global average. And there are broader implications for the economy: Agriculture is by the far the country’s biggest employer, the primary income source for some 11 million people, mostly on small farms like Purity’s.

In other words, small-scale farmers here need all the help they can get. There are countless solutions on the table, from drought-resistant seeds to hyper-local crop insurance to daily market information delivered via SMS to farmers’ cellphones. But trees might offer the lowest-hanging fruit.

“For small-scale farmers on the edge, it’s starkly obvious that trees are the future of agriculture.”

“Anything with deep roots is going to be much more resilient,” said Dennis Garrity, a senior agronomist at the World Agroforestry Centre in Nairobi. “For small-scale farmers on the edge, it’s starkly obvious that trees are the future of agriculture.”

Purity’s farm wasn’t always what Garrity calls “just short of heaven for agroforestry.” When Purity inherited this plot of land as a young bride in the late 1970s, it was mostly bare dirt with patches of couchgrass, a fast-growing weed that’s notoriously hard to remove. With her husband often gone looking for work, Purity had to learn how to be a farmer solo, by trial and error.

“I started with nothing. I was just a primitive farmer,” she recalls. “But I decided I should do all that I can to work hard to get something for myself and sustain my family.”

She started with a few pigs, but they were expensive to feed and didn’t turn a profit fast enough. So she slaughtered them, sold the meat, and bought a few sheep. They took care of the couchgrass, but then chowed through every other plant in sight, and eventually she sold them as well. Things started to turn around when, with the help of a loan from her neighbors, she rustled up the cash to buy a heifer. It bore a bull, which she sold, and also produced milk that made for steadier income than her previous livestock had been able to offer.

One of Purity's cows. (Tim McDonnell)

One of Purity’s cows. After a few years of false starts with pigs and sheep, Purity has found dairy farming to be profitable and sustainable.

But feed for the cow continued to be an onerous expense, and by this time Purity was eagerly looking for ways to grow more crops for subsistence (she eventually raised 11 children here) and to slow the steady erosion of her field into a neighboring ravine. Taking a tip from some local government agriculture advisers, in 1980 her husband planted the farm’s first sapling, a macadamia that now towers behind the cow stables.

Purity, meanwhile, went looking around the area for calliandra, a leafy shrub in the pea family that she had heard could prevent erosion and make good fodder for the cow. She picked a different plant by accident, and was disappointed by the results. But she didn’t give up, and in the early 1980s signed on to a pilot project with the government and some scientific research groups that aimed to experiment with agroforestry techniques on local farms.

“She became a farmer research agent, willing to risk a bit of her land to test different systems,” said Jonathan Muriuki, an agronomist who joined the project a few years later and has remained friends with Purity. “And what we’ve seen in the last few decades is a massive transformation.”

Muriuki estimates that Purity’s farm now supports more than 100 species of trees and shrubs (including calliandra, which grows in strategic patches alongside crops), and that at least 45 percent of the land is shaded. 

Purity has transformed, too: Where she once had never heard the word “agroforestry,” this farmer who never attended high school now rattles off the scientific names of plants like a biology professor: “These nitrogen-fixing shrubs, like tephrosia, crotalaria, and desmodium, they make the soil biodiverse by putting nitrogen into the soil, so you can make the soil fertile even without using manure or fertilizer.”

Aside from restoring soil nutrients, trees can provide other important services to climate-vulnerable farmers. They prevent soil erosion, help the soil store more rainfall, and shade crops from direct exposure to the sun. They provide alternate means of earning income, should crops fail: Trees can be trimmed for fuelwood or construction materials, or produce fruits of their own (Purity’s farm, in addition to macadamias, has several large avocado trees). Perhaps most importantly for farmers with livestock, trees provide free fodder that’s often more nutritious than store-bought dairy meal. And the nutrient-rich manure from the animals can be recycled back onto the trees and crops, instead of store-bought fertilizer.

I think you have seen my animals, they look healthy,” Purity says. “You see, instead of going to buy dairy meal, you have enough fodder trees in the farm to just harvest, every morning and every evening. [If] you go and buy dairy meal, and if you count the transport, and time wasted there, you save money. And you get enough milk, at a good quality.”

Garrity and other leading scientists and environmentalists in Kenya are trying to replicate Purity’s success on hundreds of thousands of other small farms. The Environment Ministry recently committed to restore 12.6 million acres of degraded forests, watersheds, and other important landscapes by 2030, largely by growing trees on cropland. That plan promises to make farmers more resilient to climate change without needing to invest in high-tech, expensive seeds or equipment. But Garrity cautions that it will require a sea change in how farmers envision the modern farm, which has always been associated with Western-style mono-cropping without a tree in sight.

The farm one scientist calls "just short of heaven for agroforestry.” (Tim McDonnell)
The farm one scientist calls “just short of heaven for agroforestry.”

“We’re turning the whole science around,” he said. “More and more we’re turning the corner in terms of realizing that Western agriculture just doesn’t make sense here,” especially in the context of climate change.

There’s also the challenge of thinking ahead. Big trees like Purity’s avocados can take more than a decade to mature, and even shrubs like calliandra require farmers to plan further in advance—and wait longer for a return on investment—than they may be accustomed to. And without the support from government agencies and NGOs that Purity has benefited from, neighboring farmers who may be inspired by Purity’s success wouldn’t be able to give their farms the complete agroforestry makeover overnight. In that respect, her farm is like a preview of what much of central Kenya could look like in the future, if more farmers start to follow her lead now.

Purity’s children are all grown and most have moved off the farm, a few with their own small businesses in Embu and children of their own. But Purity still wakes up at 5 o’clock every morning to milk the cows and goats. She packages the milk in plastic soda bottles, then hops the matatu (a minibus) into town to make the rounds to a regular series of customers who pay about 60 cents (U.S.) for a litre of cow milk or 45 cents for a half-litre of goat milk. Add to that the money she earns selling coffee and other cash crops, and Purity has one of the neighborhood’s highest incomes. She keeps a well-swept house, adorned with pictures of Jesus and the pope, with a television blaring the local news.

She attributes her success to the trees. She regularly travels the region to preach the agroforestry gospel to other dairy farmers, and even joined a delegation from the European Commission to the UN climate summit in Paris last December. She’s keenly aware of the high stakes for her fellow farmers.

“If we remain without making farmers aware about climate change, there will be either famine or poverty,” she says. “If we don’t have enough trees to make it better for the crops that we grow on the farm, we find that the land will remain barren, and nothing will grow there. For some time, we shall suffer.”

Tim McDonnell is a Fulbright-National Geographic Storytelling Fellow who is spending the next several months reporting on the impacts of climate change to food security in Kenya, Uganda, and Nigeria. You can follow his journey here, on the Plate blog, and on Twitter @timmcdonnell and Instagram @timothy.m.mcdonnell.


  1. Torsten Mandal
    December 4, 2016, 5:21 am

    With improved methods(!), the time needed for benefits of Calliandra calothyrsus can be reduced to 5-6 months from direct seeding in the field, and actually in within the same season for soil- and water-conservation. Making establishment easy, reliable and cheap reduces the challenges of any delay in benefits. I developed such methods in Kenya in collaboration with ICRAF, KEFRI and what is now University of Copenhagen, and published about them. In line with my advice, ICRAF changed to recommending somehow simpler and cheaper establishment methods for calliandra and similar trees, and it helped much, but the best guidelines I strongly recommend my publications and advice e.g. as freelance consultant. Some of these publicaion are with Dr. N E Nielsen.