Coffee Growing Conditions: Soil and Temperature

Coffee harvester

The following recommendations are based on the results of a decade’s research and development trials undertaken as part of a coffee research and development program that has been conducted with the co-operation of  Australian coffee growers.

The research team included horticulturists, plant nutritionists, agronomists, chemists, entomologists, physiologists, economists and engineers.

The researchers have developed production, harvesting and processing systems designed specifically for machine harvesting Arabica coffee in Australia. The requirements for establishing a machine-harvested coffee plantation in Australia are quite different to the site and infrastructure requirements of traditional hand-harvested plantations in other coffee growing countries.

The research program supported early pioneering beliefs that high quality coffee could be produced economically in Australia with machine harvesting.

An intensive system of production based on machine – harvesting does require:

  • Careful consideration of site and climate
  • A much larger capital outlay
  • Greater establishment and capital costs
  • Specific fertiliser and irrigation schedules
  • A more complex harvesting strategy and processing system
  • Machine-harvested coffee requires larger areas of level ground
  • As well, the climatic requirements during flowering and cherry ripening are more critical

While this article and a number of other Informed Farmers ‘Coffee’ articles do concentrate on the special requirements for machine-harvesting coffee, conventional coffee producers should also find aspects of the new technologies interesting and useful.

Terraced coffee plants in Vietnam

Note: To optimise yields under a machine-harvesting regime, plantation management has to be very good. Sub-optimal fertilising and irrigation can lead to substantial declines in tree yields and can lead to dieback of the trees.

Soil:

  • Overseas, most coffee is planted on deep volcanic or laterite (red, chocolate or brown) soils.
  • There are few examples of coffee being grown on sandy,shallow soils.
  • Ideally, soils should be naturally fertile, high in organic matter and at least one metre deep. Soil drainage is the most important factor as coffee does not tolerate waterlogging. Queensland and New South Wales experiences have supported these requirements.
  • Winston and O’Farrell (1993) indicated that poor soil fertility associated with sandy soils contributed to lower yields on some sites. Certainly it has been grower experience that nutritional management on sandy, shallow soils is very difficult. Poor growth associated with poor internal soil drainage has been only partly corrected with artificial drainage.

Temperature:

Consistent moisture is needed during bean "filling" or growth

Coffee evolved as a rainforest understorey tree and is poorly adapted to temperature extremes;

  • Coffee plants favour temperatures between 15°C and 25°C and as a consequence thrive in elevated tropical areas.
  • Mild temperatures during winter and spring are very important for extending cherry life, improving the synchronisation of maturity, greatly assisting mechanical harvesting and favouring floral initiation and development.
  • Extremes of heat and cold injure or kill coffee trees. Photosynthesis in coffee is slowed at temperatures greater than 25°C with tree damage at temperatures above 30°C. Cherry development is impeded above 30°C.
  • Coffee trees are killed by frost and injured below 3°C, while temperatures below 7°C restrict growth (Willson,1985). Winston and O’Farrell (1993) identified that high temperatures limited coffee production in some areas of North Queensland. Low yields at Southedge Research Station near Mareeba, were attributed to temperature extremes during periods of rapid plant growth. Coffee is highly susceptible to frost and even short periods below 0°C will defoliate the tree. Overhead irrigation has been used to protect coffee from frost on small plantations. To be successful the irrigation system must be capable of irrigating the whole plantation at one time. This has not been practicable on the larger farms required for machine-harvesting.

There are more Informed Farmers articles listed under ‘Coffee’ that likewise relate to the site, environmental, financial and managerial requirements for the successful development of a machine-harvested coffee plantation.

Source: Terry Campbell, Senior Extention Horticulturist, QLD Dept of Primary Industries, Mareeba.