Banana systems in Rwanda. Photo by IITA

What happens when banana and coffee are grown together? Farmers earn more, say IITA scientists and partners.

Growing coffee and banana forms the economic base for most of the small-scale farmers in much of Uganda and the surrounding highlands of Rwanda, Burundi, northwest Tanzania, and eastern Democratic Republic of Congo.

Banana is an important food staple in Uganda produced all year round; farmers sell surplus yield on a daily basis. Coffee, on the other hand, is a pure cash crop, cultivated on over half a million coffee farms, 98% owned by smallholders. It is a major foreign exchange earner for the Great Lakes countries. In Uganda, for example, it generates some 20% of the country’s foreign exchange revenues. Robusta coffee is dominant below 1400 meters altitude, Arabica at higher altitudes.

In some densely populated areas, banana-coffee intercropping is practiced, but it is not common. Some countries even recommend that coffee be grown as a sole crop. Some farmers, however, report on the advantages of growing coffee under bananas, such as providing shade, mulch, nutrients, and moisture. For instance, farmers use coffee husks to replenish nutrients in banana and coffee fields, although this is discouraged by Robusta coffee growers to prevent the spread of coffee wilt disease. Meanwhile, some researchers also cite advantages such as reduced erosion in the highlands.

The crops complement one another in terms of socioeconomic benefits to growers and farm families. Bananas provide permanent food and income security, doubling as a primary food and cash crop, and providing a modest but continuous cash flow throughout the year. Coffee gives a cash boom twice a year, helping farmers acquire funds for more expensive items such as infrastructure, farm inputs, transport equipment, and large social events.

Drying coffee beans in Uganda. Photo by IITA

So how effective is intercropping? R4D Review editors asked IITA agronomist Piet van Asten who works on banana-based systems in IITA-Uganda.

“Despite farmers’ beliefs and practices, perceived benefits, and some positive indications, there are no official recommendations or advice about intercropping,” he said. “There has been no research about this until now.”

“Banana and coffee intercropping is much more profitable than either banana or coffee monocropping,” reports van Asten and the team of scientists who conducted a diagnostic survey in seven districts in Uganda.

IITA collaborated with the Agricultural Productivity Enhancement Program (APEP-USAID) to study some 150 APEP demo plots of banana and coffee monocrop and intercrop fields, and 150 farmer control fields in the major banana-coffee growing areas from southwest to east Uganda. The demo plots were farmers’ fields where APEP extension officers provided fertilizer and stimulated the adoption of best crop management practices, such as mulching, pruning (coffee), or desuckering (bananas).

Information on resource use, including external inputs, labor, land, and farmgate prices were obtained through structured farmer interviews in 2006-2007; data on crop production, soil fertility, pest and disease pressure, and management practices were quantified through field visits.

“Study results were beyond our expectations,” van Asten pointed out. “In the Arabica-growing area around Mt. Elgon, coffee yields were similar in monocropped and intercropped coffee—even when the demo plots were fertilized. The number of coffee trees per hectare decreased slightly when intercropped, but yields per tree were higher.”

In the Robusta-growing areas, intercropping reduced coffee yields slightly (by 13%) when the fields were not fertilized, but when they were fertilized coffee yields were the same in monocropped and intercropped fields. In general, banana yields suffered when intercropped with Robusta coffee but not from intercropping with Arabica coffee, (Table 1).

Because the coffee yields were not affected, the additional banana production increased the revenue of banana-coffee intercropped fields by 50-60% compared to monocropped coffee fields (Table 2). These figures show that banana-coffee intercropping is much more profitable than sole planting of either crop, van Asten and IITA and APEP colleagues concluded.

“For instance, in the Arabica coffee-growing region around Mt. Elgon, annual returns per hectare averaged US$4,441 for intercrop, $1,728 for banana monocrop, and $2,364 for coffee monocrop. In Robusta-growing areas in South and Southwest Uganda, annual returns per hectare averaged $1,827 (intercropping), $1,177 (banana monocrop), and $1,286 (coffee monocrop). These results are for the nondemo plots,” he said.

Why did this happen? Coffee plants are shade loving and bananas are taller, so there is not much light competition. Potassium is an important nutrient for both crops, and the intercropped coffee seemed, on average, to be less potassium deficient than sole coffee. This may be due to the very high biomass turnover in the banana system. The mulch may reduce the need for soil tillage, thereby keeping the shallow banana and coffee rooting systems intact. The high biomass turnover may also bring nutrients into forms more easily available for the plants. “There could be other reasons, but the findings thus far at least indicate that the intercrop system does have some strong advantages,” van Asten said.

“More research is needed. We have to understand how this works so we can apply the findings to other banana and coffee-growing areas.”

“We also need to come up with recommendations to help farmers exploit this opportunity to improve productivity and revenues, without purchasing additional inputs or increasing the area under cultivation. Land pressure and lack of credit or capital are two major constraints for African smallholder farmers.”