Climate change to push Ethiopian coffee farming uphill

This article was republished from SciDev.Net.

By Baraka Rateng’

Relocating coffee areas, along with forestation and forest conservation, to higher altitudes to cope with climate change could increase Ethiopia‘s coffee farming area fourfold, a study predicts.

The study, published in Nature last month (19 June), suggests that moving Ethiopian coffee fields to higher ground because of climate change could increase resilience by substantially increasing the country’s suitable production area.

Justin Moat, spatial analyst at the UK’s Royal Botanic Gardens Kew, and lead author of the study, says that currently coffee farming is mainly confined to altitudes between 1200 and 2200 metres.

“A critical factor in the suitability of coffee farming is the interaction between rainfall and temperature.”

Justin Moat

“In general, coffee’s niche will move uphill to keep to optimal temperature,“ he tells SciDev.Net. “Much work would be needed to achieve this if planning starts now.”

According to Moat, up to 60 per cent of the country‘s current production area could become unsuitable before the end of the century.

Ethiopia, he says, is the world’s 5th largest coffee producer. The crop provides a quarter of export earnings, and approximately 15 million Ethiopians engage in coffee farming and production.

The study‘s results were based on computer modelling and simulations. “We determined coffee-preferred climate (niche) using a huge amount of data collected on the ground, including historic observations, overlaid on climate maps,” explains Moat.

They projected this niche into the future using climate models and scenarios, which revealed that all the models were in general agreement. They then combined this with satellite imagery to come up with the present-day forest coffee area, and the area projected in the future.

Higher altitudes are forecast to become more suitable for coffee while lower altitudes are projected to become less suitable, according to the study.

“A critical factor in the suitability of coffee farming is the interaction between rainfall and temperature; higher temperatures could be tolerated if there was an increase in rainfall,” Moat notes.

He adds that regardless of interventions, one of the country‘s best known coffee-growing regions — Harar, in eastern Ethiopia — is likely to disappear before the end of the century.

Shem Wandiga, a professor of chemistry at the University of Nairobi’s Institute for Climate Change Adaptation, Kenya, says that although the study cannot predict with full certainty, it holds important messages for policymakers.

“Start planning to expand coffee growing areas to higher elevation, he suggests. “The expansion should be coupled with forestation of the areas.“

Copyright: Panos

Researchers and policymakers should also map out the human, social and ecological conditions that may allow such expansion, according to Wandiga. Also, farmers should slowly substitute coffee with other plants that may bring income.

William Ndegwa, Kitui County director at the Kenya Meteorological Department, says the model used in the research is a powerful tool for linking climate variables with biological parameters.

“This is a very interesting [study] with deep insights into the characteristics of the impacts of climate change on crop production,” he notes.

This piece was produced by SciDev.Net’s Sub-Saharan Africa-English desk.

 

This article was originally published on SciDev.Net. Read the original article.

Fighting Fusarium wilt to beat the bananapocalypse

Dr. Sarah Schmidt (@BananarootsBlog), Researcher and Science Communicator at The Sainsbury Laboratory Science. Sarah got hooked on both banana research and science writing when she joined a banana Fusarium wilt field trip in Indonesia as a Fusarium expert. She began blogging at https://bananaroots.wordpress.com and just filmed her first science video. She speaks at public events like the Pint of Science and Norwich Science Festival.

 

Every morning I slice a banana onto my breakfast cereal.

And I am not alone.

Every person in the UK eats, on average, 100 bananas per year.

Bananas are rich in fiber, vitamins, and minerals like potassium and magnesium. Their high carbohydrate and potassium content makes them a favorite snack for professional sports players; the sugar provides energy and the potassium protects the players from muscle fatigue. Every year, around 5000 kg of bananas are consumed by tennis players at Wimbledon.

But bananas are not only delicious snacks and handy energy kicks. For around 100 million people in Sub-Saharan Africa, bananas are staple crops vital for food security. Staple crops are those foods that constitute the dominant portion of a standard diet and supply the major daily calorie intake. In the UK, the staple crop is wheat. We eat wheat-based products for breakfast (toast, cereals), lunch (sandwich), and dinner (pasta, pizza, beer).

In Uganda, bananas are staple crops. Every Ugandan eats 240 kg bananas per year. That is around 7–8 bananas per day. Ugandans do not only eat the sweet dessert banana that we know; in the East African countries such as Kenya, Burundi, Rwanda, and Uganda, the East African Highland banana, called Matooke, is the preferred banana for cooking. Highland bananas are large and starchy, and are harvested green. They can be cooked, fried, boiled, or even brewed into beer, so have very similar uses wheat in the UK.

In West Africa and many Middle and South American countries, another cooking banana, the plantain, is cooked and fried as a staple crop.

In terms of production, the sweet dessert banana we buy in supermarkets is still the most popular. This banana variety is called Cavendish and makes up 47% of the world’s banana production, followed by Highland bananas (24%) and plantains (17%). Last year, I visited Uganda and I managed to combine the top three banana cultivars in one dish: cooked and mashed Matooke, a fried plantain and a local sweet dessert banana!

 

Three types of banana in a single dish in Uganda.

Another important banana cultivar is the sweet dessert banana cultivar Gros Michel, which constitutes 12% of the global production. Gros Michel used to be the most popular banana cultivar worldwide until an epidemic of Fusarium wilt disease devastated the banana export plantations in the so-called “banana republics” in Middle America (Panama, Honduras, Guatemala, Costa Rica) in the 1950s.

Fusarium wilt disease is caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (FOC). The fungus infects the roots of the banana plants and grows up through the water-conducting, vascular system of the plant. Eventually, this blocks the water transport of the plant and the banana plants start wilting before they can set fruits.

Fusarium Wilt symptoms

Fusarium Wilt symptoms

The Fusarium wilt epidemic in Middle America marked the rise of the Cavendish, the only cultivar that could be grown on soils infested with FOC. The fact that they are also the highest yielding banana cultivar quickly made Cavendish the most popular banana variety, both for export and for local consumption.

Currently, Fusarium wilt is once again the biggest threat to worldwide banana production. In the 1990s, a new race of Fusarium wilt – called Tropical Race 4 (TR4) – occurred in Cavendish plantations in Indonesia and Malaysia. Since then, TR4 has spread to the neighboring countries (Taiwan, the Philippines, China, and Australia), but also to distant locations such as Pakistan, Oman, Jordan, and Mozambique.

Current presence of Fusarium wilt Tropical Race 4. Affected countries are colored in red.

In Mozambique, the losses incurred by TR4 amounted to USD 7.5 million within just two years. Other countries suffer even more; TR4 causes annual economic losses of around USD 14 million in Malaysia, USD 121 million in Indonesia, and in Taiwan the annual losses amount to a whopping USD 253 million.

TR4 is not only diminishing harvests. It also raises the price of production, because producers have to implement expensive preventative measures and treatments of affected plantations. These preventive measures and treatments are part of the discussion at The World Banana Forum (WBF). The WBF is a permanent platform for all stakeholders of the banana supply chain, and is housed by the United Nation’s Food and Agricultural Organization (FAO). In December 2013, the WBF created a special taskforce to deal with the threat posed by TR4.

Despite its massive impact on banana production, we know very little about the pathogen that is causing Fusarium wilt disease. We don’t know how it spreads, why the new TR4 is so aggressive, or how we can stop it.

Fusarium Wilt symptom

Fusarium Wilt symptoms in the discolored banana corm.

Breeding bananas is incredibly tedious, because edible cultivars are sterile and do not produce seeds. I am therefore exploring other ways to engineer resistance in banana against Fusarium wilt. As a scientist in the 2Blades group at The Sainsbury Laboratory, I am investigating how we can transfer resistance genes from other crop species into banana and, more recently, I have been investigating bacteria that are able to inhibit the growth and sporulation of F. oxysporum. These biologicals would be a fast and cost-effective way of preventing or even curing Fusarium wilt disease.

 

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