An African grass comes home for good – Part 2: Biodiversity to the rescue

23 October, 2014 by (comments)

Of all the efforts now underway to incorporate improved Brachiaria grass into Africa’s mixed farming (see part 1 in this blog series), the biggest and most successful was prompted less by its well-known value as livestock feed and more by another important role for the grass that CIAT scientists never imagined. This and other experiences with Brachiaria are summarized in a paper prepared recently by CIAT forage scientist Brigitte Maass, together with eight other scientists working in the region, which she presented in late October at the Sixth All-Africa Conference on Animal Agriculture, held in Nairobi, Kenya.

Hollywood plot

A few years ago, entomologists at the International Centre of Insect Physiology and Ecology (icipe) determined that Brachiaria serves quite well as a “trap” crop, attracting and aiding the destruction of stem borer, a devastating insect pest of maize and other cereals. For this purpose, scientists incorporated the grass into a novel and much-celebrated crop production technology called “push-pull.”

It’s the brainchild of icipe entomologist Zeyaur Khan, who has meticulously refined and tirelessly promoted the practice since he and his team first developed it during the mid-1990s in collaboration with Rothamstead Research in the UK and various African partners. Through a series of studies with more than 60 different grass species, the icipe team selected Brachiaria for use in push-pull, partly because of seed availability but especially because of the grass’s drought tolerance. Brachiaria has thus made the latest edition of the push-pull approach “climate smart,” permitting its extension into drier areas. In the conventional version, Napier grass serves as the trap crop and does well under adequate rainfall.

Kennedy Anyango, an icipe research technician, screening Brachiaria and other grasses for drought tolerance at the Center’s Mbita Point Field Station on the shores of Lake Victoria in western Kenya.

The inner workings of push-pull are extraordinary. Even Hollywood would be hard pressed to invent a plot as elaborate as that of the drama unfolding in push-pull fields. Superficially, all is order and symmetry. Small plots of maize or sorghum are bordered on all sides with two or three rows of Brachiaria grass. Farmers sow a forage legume, Greenleaf Desmodium, between the rows of cereals.

Behind the scenes, Desmodium gives stem borers a push, Khan explains at the Mbita Point field station, through volatile chemicals that repel the insect pest. In a particularly bizarre plot twist, the legume also chemically prompts seed of the parasitic weed Striga (another major crop pest) to germinate but then prevents the weed from latching onto the cereal’s root system, the means by which Striga normally grows and reduces crop yields. In effect, Desmodium drives Striga to suicide. The plot further thickens, when Brachiaria gives stem borers a pull, chemically enticing them to come and lay their eggs, while simultaneously calling in natural enemies to destroy the pests.

Entomologists are by training holistic thinkers, especially the ones who, like Khan, don’t believe in dumping lots of pesticides on crops. It therefore comes as no surprise that these specialists were able to find such an elegant and clever way to incorporate tropical forages into Africa’s mixed farming for pest control and other purposes. Their grasp of the whole production system in which crop pests develop made it possible for them to envision a new and amazingly effective role for agricultural biodiversity.

Obama family ally

At first, the push-pull system sounds pretty strange and complicated. So, what do farmers make of it? Actions speak louder than words, and large numbers of smallholders have adopted the practice in Kenya, Ethiopia, Tanzania, and Uganda. More than 30,000 have taken up climate-smart push and pull on top of the tens of thousands more who had already embraced the conventional version.

In Kenya’s Siaya District, farmer Richard Amolo (right) explains to icipe research technician Dickens Nyagol how more than 20 neighboring farmers have followed his example to adopt the push-pull technology developed by icipe and its partners.

But words are powerful too. And as a result of the thorough manner in which Khan and his team have communicated the practice through networks of district farmer teachers (with the support of the European Union and in close collaboration with Kenya’s Ministry of Agriculture), many smallholders can explain in detail the principles of push-pull and the multiple benefits it offers them. Naturally, they welcome the disappearance of stem borers and Striga from push-pull plots, which farmers establish where continuous cultivation has reduced soil fertility, making crops more susceptible to these pests.

This is what first got the attention of “Mama” Sarah Obama, the step-grandmother of US president Barack Obama. She lives at K’ogelo village in Siaya District, the ancestral homeland of the president’s father. In a conversation with Zeyaur Khan several years ago, Mama Sarah shared her concern about Striga, which she warned “is destroying the livelihoods of the Luo people.” After Khan explained how push-pull drives out Striga, she decided to introduce the approach in a half-hectare maize field at the entrance of her compound, which receives literally busloads of visitors every week. With its pale blue metal sign identifying the push-pull plot as Mama Sarah’s, this must be the most frequently visited agricultural demonstration plot in Kenya, if not all of Africa or even the whole world. Mama Sarah has become a goodwill ambassador for push-pull and is a strong promoter at 93 years old.

Farmers nearby are also enthusiastic about using Brachiaria together with Desmodium as livestock feed. Syprose Aruma Apado, for example, describes how her well-nourished milk cow has more than doubled its production, and she’s not worried about having enough feed for a newborn calf. In the drier setting of Lambwe Valley on the other side of Winam Gulf, Rose Wasenga remarks that Brachiaria hybrid Mulato II is “so soft and sweet,” meaning that it’s easy to cut, not irritating to the skin, and highly palatable for her goats. She adds that the grass rows also curb erosion, pointing for emphasis across her gently sloping field.

Neighboring farmers bring in additional cash by selling bales of Brachiaria and Desmodium for feed. Samuel Sana, whose farm is somewhat larger than average in this area, earned so much that he was able to establish a school for HIV/AIDS orphans, who learn about push-pull and other new techniques.

In recent years, Khan and his team have begun working a lot with farmer groups. “This is more efficient,” says Dickens Nayagol, an icipe research technician, “and better enables farmers to draw on assistance from NGOs like Send a Cow and Heifer International.” Charles Odhiambo leads one such group and actively reaches out to others. “Charles interacts with up to 100 farmers, helping to spread new knowledge far and wide,” says Nayagol. Another local group consisting entirely of women calls itself “Seeing is Believing.”

Mexican seed revolution

Brigitte Maass is pleased with farmers’ largely positive reaction to Mulato II, but precisely because of the enthusiastic response, she’s also a bit worried. “Overselling one outstanding grass can increase the vulnerability of smallholder dairy farming to changing pest and disease pressures and eventually lead to a repeat of the recent disaster with Napier,” says Maass. In fact, icipe entomologists have already sounded the alarm about the damage that shootflies sometimes cause to Mulato II when it’s first getting established.

The Rwanda Agriculture Board (RAB) is testing Brachiaria grass, and producing both seed and hay at its Karama Research Station in Bugesera District.

“To counter these problems, we have to introduce and test a wide range of materials, which can fit different ecological and production niches across the region,” says Maass. For this purpose, Zeyaur Khan at icipe has already obtained new Brachiaria grasses, which are being tested at field stations and in farmers’ fields for the push-pull approach.

Another key player in this effort is Grupo Papalotla, which has supplied seed to icipe for its work on push-pull and is now setting up a production and marketing operation in Kenya. The resulting Mexican seed revolution will help make improved Brachiaria grasses a common and useful feature of agricultural landscapes throughout this part of Africa.

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Filed Under: Africa @en, Crop diversity, Crops @en, Regions, Tropical Forages