Dar es Salaam –
11 December 2012. Growing coffee and banana together not only
generates more income for small-holder farmers, compared to growing
either crop alone, but it can also help coffee production to better
cope with the effects of climate change, a recent study has shown.
The study, which sought to understand the potential impact of climate
change on coffee-based livelihoods in the East African highlands,
found that the areas suitable for growing Arabica coffee will
drastically decrease in the future leading to losses in the region
that may exceed US$100 million annually. This is not only a threat to
the countries’ foreign revenue, but it also puts at risk the
livelihoods of millions of small-holder farmers depending on the crop.
The researchers from the International Institute of Tropical
Agriculture (IITA) in collaboration with those from the
Colombian-based International Center for Tropical Agriculture (CIAT),
used climate models and climate analogues to predict the impact of
climate change on coffee production. The researchers walked down the
slopes of Rwenzori Mountains, in Uganda, where the lower one goes, the
temperatures get progressively warmer and drought stress becomes a
more serious problem—similar to walking into a “future climate”.
The approach illustrated that areas below 1300 m may well become
completely unsuitable for Arabica coffee production. In areas between
1300-1700 m, coffee will be severely affected if current farming
practices that use traditional varieties and make limited use of water
conservation and shade technologies remain unchanged.
In Uganda, coffee is the most important export crop generating
approximately 20% of the foreign exchange earnings. One-third of the
coffee export value is from Arabica coffee, which requires a
particularly cool tropical climate that is only found at higher
altitudes, generally above 1400 m. Arabica is therefore very sensitive
to a rise in temperature induced by climate change. Coffee is also
among the top three commodity exports in Ethiopia, Rwanda, Burundi,
and Tanzania.
Shade provided by shade trees or banana can help coffee to cope with
the warmer climate and with drought shocks. Research has shown that
shade can reduce the temperature in the understory plants by up to 2º
C or more. Past research by IITA also showed that growing coffee and
banana together increased the farmers’ income – the coffee yield
remained the same despite creating room for the banana and the farmer
gained additional income from selling the banana. This study
strengthens the case for growing coffee and banana together as it
provides both short- and long- term benefits to farmers.
“Strategies to help farmers cope with climate change will often be
more successful if farmers are also able to see the immediate benefit
of their investment. By growing banana and coffee, in a year’s time,
the farmers will be earning extra money from selling banana,” says Dr
Piet van Asten, an agronomist with IITA based in Uganda and one of the
researchers. “And if coffee fails, then bananas will still provide the
farmer with food and income. It is a perfect win-win situation for
both crops and the farmers.”
The researchers also interviewed farmers in the region who said the
climate was already changing—the droughts were becoming longer,
rainfall was becoming more erratic, and the rainy seasons were
becoming shorter. This negatively affected the flowering of coffee and
reduced the sizes of the berries.
The farmers had also observed that pests and diseases such as leaf
miners, coffee berry borers, mealy bugs, and leaf rust were on the
rise. However, the study found that leaf rust incidences were 50%
lower in coffee that was shaded by banana compared to the unshaded
plants.
The findings are supported by another study by Alessandro Craparo from
the University of Witwatersrand with support from IITA, CIAT, and
CGIAR Consortium Program on Climate Change and Agricultural Food
Security (CCAFS) and the Tanzania Coffee Research Institute (TaCRI)
that is looking at the influence and impact of climate change
variability on Arabica coffee in the Mt Kilimanjaro area. It found
that every minimum temperature increase of 1º C would lead to a yield
loss of almost 100 kg/ha, representing 20% of the current yield.
The only drawback to adding shade to coffee is that it demands more
nutrients and farmers will have to invest in maintaining the soil
fertility.
“The downside of adding shade or shade crops to a coffee system is
that it increases competition among the different plants for water,
nutrients, and light. This competition needs to be managed by using
good agronomic practices such as integrating fertilizers and organic
nutrient inputs, appropriate plant density and canopy management, and
good soil and water conservation practices to adapt successfully to
climate change,” Dr Van Asten said.
The studies on impact of climate change on coffee systems in Uganda
received support from Climate Change, Agriculture and Food Security
(CCAFS), the Consortium for Improving Agriculture-based Livelihoods in
Central Africa (CIALCA) project, Oxfam, USAID, Wageningen University
(WUR), and a wide range of coffee sector partners in the region.