Growing coffee in the shade: Towards agricultural sustainability in Colombia.

William Andrés Cardona is the winner of a Rudolf Agricola PhD Grant. With this grant, he can evaluate different sustainable indicators in forty coffee farms in the Meta department in central Colombia for his research:

'In Colombia, coffee plantations are often established in mountainous areas at an altitude of about 1200 meters. The Meta department is an exception to this; it is lower and much flatter. Farmers there now cultivate monocultures of coffee plants, but we believe it can be much better with agroforestry. There is a lot of space between the coffee plants where other crops and trees can be planted, which benefits sustainability.'

There is an awful lot of coffee in Brazil!' goes the famous song. Colombia however, is often associated with an infamous product: cocaine. The Colombian government now is trying to change that. Coffee can grow well in many parts of Colombia also, and it offers a good alternative for Colombian farmers. But how do you grow coffee as sustainably as possible? This is being researched by William Andrés Cardona, a PhD student at the University of Groningen, under the guidance of Professor Pablo Tittonell. Cardona: 'Colombia has an agricultural institute that has been researching coffee cultivation for a hundred years. Yet they do not conduct scientific research in Meta because the area is still considered too dangerous and not significant.'

Trees to reduce heat

Cardona's research began in September 2022, and in August 2023, farmers planted coffee plants according to principles developed together with Cardona and Tittonell. Latin America was once known for its 'three sisters agriculture.' Indigenous farmers planted corn, beans, and squash together. Europeans, used to monocultures, found that messy, but this mix worked well for the soil, against pests, and yielded a good harvest without pesticides and fertilizers. Cardona's new system seems to be a modern variation of this. 

Cardona: 'Despite the presence of illegal groups in the region, coffee production offers a good opportunity for legal economic development. However, the agro-ecological conditions in the south of Meta require a different approach to coffee cultivation than in other Colombian regions. Farmers have now, in consultation with us, planted other crops and trees between the coffee plants. Trees can help reduce extreme heat with their shade and increase the yield of food crops. This creates systems that make the depleted soil fertile again by adding organic matter. Meta is known for producing plantains and cassava, which have a growing demand. Avocado cultivation also offers potential for the local market, creating opportunities to sell the additional crops.'

What's the best mix?

While monoculture plantations can increase production in the short term, they are harmful to the environment. The soil quickly loses its fertility, and biodiversity decreases. Moreover, these plantations are vulnerable to climate change. Cardona hopes that his method of crop diversification will increase biodiversity and agricultural productivity and be good for the soil. By growing different plants together, they are more resistant to diseases and there is less need for fertilizers and pesticides. However, the question remains: what is the best mix of plants? 

Cardona: 'We have established plantations with different ground covers and crops, including avocado, plantain, corn, beans, pigeon peas, and cassava. We measure the effects on ecosystem services such as carbon sequestration, soil quality, and food security. We conducted measurements before introducing the new plants and are now monitoring how the soil and plants develop.

Coffee plants only yield after two years, so farmers would not have earned anything until now. By growing other crops between the coffee plants, they earn from the beginning. We are also investigating what the farmers do with those products: do they sell the yield, eat it themselves, or use it to feed animals?

With climate change in mind, we are also looking for alternative crops for areas becoming less suitable for coffee. Ultimately, we expect to gain a lot of knowledge that will make coffee cultivation more sustainable and environmentally friendly, and also ensure farmers a good yield.'