Roughly, five types of coffee production systems can be distinguished (Moguel, 1996, in Courville, forthcoming):
1)Traditional rustic coffee system: coffee production under forest trees by substitution of plants growing on the floor of a (sub)-tropical forest with coffee. There is a minimal impact on the original forest ecosystem;
2)Traditional polyculture system ('coffee garden'): involving the manipulation of the native forest ecosystem. This is a subsistence system where the strata composition is based on dynamic use and multi-species (native and non-native) composition of the shade. The system is linked to other crops associated with coffee.
3)Commercial polyculture system: the original forest canopy trees are replaced by a commercially useful set of shade trees. The main strategy is to obtain two or more products from the same plot. The associated species provide shade for the coffee trees as well as an extra product. Corn, macademia, Valencia orange, red cedar, pepper and avocado are commonly used intercrops.
4)Shaded monoculture system: One indigeous shade species is planted as a canopy to protect the monospecific coffee plantation underneath;
5)Open sun monoculture system: involving the use of sun tolerant coffee cultivars that do not require shade. This coffee production system is typified by improved varieties, high densities, high inputs of chemical fertilizers and pesticides, high financial investments,the use of machinery, intensive use of labour and the highest yields.
During the last 30-40 years, substantial transformation of coffee systems in Central America, particularly in Costa Rica has taken place. Many multi-strata traditional coffee systems (rustic coffee under shade of forest species) have been converted to highly intensified coffee monoculture: dwarf coffee planted at very high densities (5,000 to 10,000 trees/ha), little or no shade, and frequently treated with herbicides and other phytosanitary products.
Elements in the coffee production
Any coffee production system involves the following elements:
1.Managing the coffee farming system = planting and renovation of the coffee plots through
- Establishing coffee nurseries: propagation generally takes place by seed from ripe cherries of selected trees.
- Transplanting seedlings
- Fertilisation: the most important nutrients for coffee are nitrogen, phosphate, poash, calcium, magnesium plus a number of minor elements (zinc, iron, manganese, copper, sulphur and boron)
- Weed control
- Disease control: one of the most common diseases is leaf rust (Hemileia vastatrix).
- Pest control: the coffee cherry borer (Hypothenemus hampei) is one of the most serious coffee pests. The beetles breed in dry berries left on the tree or that fell on the ground at the end of the harvest season.
- Shade regulation
- Pruning and stumping
- Selection of preferred ground cover plant species
- Establishing live or dead barriers to reduce erosion
Only ripe red coffee berries should be picked. Harvesting is mainly done by hand but occasionally mechanical harvesting may take place. Harvesting is a labour intensive process that involves recruiting large numbers of people, including the family, friends and hired labour. As the berries do not ripen all at the same time, the harvest season may last for up to four months over a number of pickings.
3. Wet and dry processing
Wet processing closely follows the harvesting. At the wet processing site the coffee cherries are dumped in the water where the poor quality floating berries will be separated from the rest. Depulping is done either by hand or mechanically depending on the size of the processing site. The cherry pulp is rich in nutrients and is often put back into the coffee plot in the form of compost. After depulping the coffee will undergo a fermentation process, in order to get rid of the remaining slimy mucilage layer. After a standard set of time, the coffee beans are washed and then dried. The drying process can take place in the sun or in large electric or fossil fuel dryers. When completely dry, the parchment coffee, so called due to the parchment like shell around each individual bean, is discarded from stones, sticks and other waste particles before it is sent to the dry processing plant. Here it will be transformed through a mechanical process into green coffee.
4. Grading and packing
The green bean is put through a number of processes that help to sort it according to weight, size, shape and colour. In this way different export and domestic grades are achieved. Finally the green beans are put into jute bags of 60 kilograms and shipped to importing countries in quantities of 250 bags.
Pesticide use within coffee production
Industrial coffee production often employs chemicals that present serious health and ecological concerns. The roasting process reduces detectable levels of pesticide residues on bean samples. Sampling of imported green coffee beans conducted by the U.S. Food and Drug Administration (FDA) in the late 1970s and early 1980's revealed frequent detections of DDT, BHC and other pesticides banned in the U.S. Other tests using detection methods many times more precise than the FDA procedures revealed multiple pesticide residues on all samples of green beans.
Negative environmental effects
Modernisation of coffee culture resulted in:
- Important gains in productivity;
- Decreased plantation longevity;
- Los of soil fertility following the elimination of shade trees. The reduced quantity of litter covering the soil does not impede erosion. The excessive use of nitrogen fertilizers causes a progressive soil acidification.
- Negative long-term environmental impact at local level.
At regional level intensive coffee cultivation also has negative long term environmental effects such as loss of floral and faunal diversity, and contamination of groundwater by agrochemicals such as nitrates and pesticides.
Side effects of the wet and dry processing
Large quantities of water are used in the washing process after fermentation. The wastewater has a very high organic content that, historically, was dumped back in the river. Nowadays a number of new technologies such as semi-washed or dry processing have been developed to reduce the water used and the pollution caused in this proces.
Dry processing is an energy intensive process and takes place at large plants.
Light distribution, microclimate and soil fertility are mainly influenced by shade trees.