Intercropping with macadamia protects coffee and boosts yield

The study also shows that combining these two crops is a powerful survival strategy in an era of climate change and raises farm incomes.

By José Tadeu Arantes  |  Agência FAPESP – Brazil is by far the world’s largest coffee producer, with production estimated at 49.7 million 60 kg bags in 2016. Consolidated data for 2015 show Brazil producing 43.2 million bags, Vietnam 27.5 million, Colombia 13.5 million, Indonesia 11 million, and Ethiopia 6.4 million. Brazil’s coffee groves total 2.26 million hectares in area, with 290,000 owners and more than 8 million workers.

This vast agroindustrial segment has its Achilles heel, however: coffee is the only crop grown on over 90% of the properties concerned. In recent decades, the negative effects of monocropping have become familiar to specialists. These effects include soil erosion, loss of biodiversity and high production costs associated with the use of fertilizers and pesticides.

Intercropping is a successful alternative. A research project supported by FAPESP focused specifically on intercropping of coffee and macadamia: “Intercropped growth of Arabica coffee (Coffea arabica L.) and macadamia nut (Macadamia integrifolia Maiden & Betche) cultivars”.

The researchers involved in the project, Rogério Peres Soratto from São Paulo State University’s Botucatu School of Agricultural Sciences (FCA-UNESP), and his former PhD supervisee Marcos José Perdoná, now with the São Paulo State Agribusiness Technology Agency (APTA), recently published an article in the American Society of Agronomy’s Agronomy Journal entitled “Arabica coffee-macadamia intercropping: a suitable macadamia cultivar to allow mechanization practices and maximize profitability”.

The publication, also supported by FAPESP, was widely reported by specialized online media in the US, as can be seen on the websites of the Soil Science Society of America, the Crop Science Society of America, and the American Society of Agronomy, among others.

“From the environmental standpoint, intercropping contributes to soil conservation and fertility, promotes biodiversity, and helps defend crops against some weed species. In economic terms, it optimizes land and manpower use during the year, increasing producers’ income and protecting them from the effects of adverse weather and market fluctuations,” Soratto told Agência FAPESP. “In short, it makes the system much more sustainable. In addition, it raises the yields of both crops and supports mechanized coffee harvesting.”

Another very important benefit of intercropping, which the researchers had already emphasized in a previous article, is a reduction in the vulnerability of coffee crops to global climate change. Rising average temperatures tend to make some areas no longer suitable for coffee growing, forcing geographic reconfigurations and resulting in serious economic and social losses.

“C. arabica is an evergreen shrub that originally developed in the shade of taller trees. High temperatures and water shortages damage it severely and lower its reproductive performance,” Soratto said. “Intercropping coffee with macadamia nut trees mitigates these effects and protects coffee groves from other climate-related risks, such as withering from exposure to sunlight, frost and wind.”

The experiment, conducted by Soratto and Perdoná in the Dois Córregos region of São Paulo State, showed that intercropping increased Arabica coffee output by 10% without irrigation, i.e., when watered only by rainfall. Drip irrigation enhanced growth in intercropped plantations, raising coffee and macadamia yields by 60% and 133%, respectively.

Furthermore, intercropping enables farmers to harvest two crops instead of one, significantly enhancing their commercial performance and helping them survive the adverse conditions caused by price drops. 

Macadamia is an evergreen woody nut tree that prefers subtropical climates and is native to Australia. Its nuts fetch high market prices, both shelled and whole. Its economic potential has not yet been extensively developed in Brazil. 

In the experiment, the two crops were planted at the same time, coffee plants in rows 3.5 m apart and with 70 cm between plants, and macadamia trees in rows 10.5 m apart and with 4.9 m between trees, interspersed so that each row of macadamia with coffee was separated from the next by two rows of coffee [see photo above].

“We evaluated the development of both crops for eight years after planting,” Soratto said. “Coffee plants are usually considered to produce profitably for between 15 and 20 years, but this limit is determined much more by crop management than by aging. There are well-managed plantations that remain productive for far longer.”

Demanding consumers

Although Brazilian coffee is sometimes considered inferior to coffee from other countries such as Colombia, for example, there are currently small-scale brands in Brazil that certainly rival the best brands of other countries in terms of quality. The number of more demanding consumers is also growing; although still in the minority, these coffee lovers appreciate characteristics such as flavor, body, aroma, acidity, bitter and sweet tones, and aftertaste or finish.

Intercropping might ultimately help improve coffee quality further, adding specific tones to flavor and aroma due to proximity with macadamia. However, the study did not cover this aspect, focusing instead on sustainability and yield. 

“We didn’t evaluate beverage quality because that would have required a different kind of study with a large amount of fine-grained detail,” Soratto said. “Shade-grown coffee is known to produce better-quality beans, since they ripen more slowly and more completely. But any slips in harvesting, drying or roasting can impair their quality. First-class beans can be spoiled by mistimed harvesting or inadequate post-harvest management.”

In a new project supported by FAPESP, the researchers are now studying how to insert macadamia into existing coffee plantations and the feasibility of totally mechanized coffee harvesting in these systems.

Another experiment is ongoing to study macadamia pruning management, since there comes a time when coffee plants become too shaded due to the nut trees’ growth. Coffee plants rarely exceed 4 m in height, whereas macadamia trees can reach 25 m. Managing both at the same time requires specific procedures after several years of intercropping.