The Jamaican coffee phenology scenario

By Gustland McCook, Regional Advisory Officier Coffee Industry Board

In Jamaica coffee is traded mostly in the form of fruits, that is to say, the farmer, after harvesting his coffee, sells it to a processor in the form of ripe cherry coffee. On receival at the wet mill the product is classified, sorted and processed.

The phenology profile of the Jamaican coffee is determined by the micro-climate of the various altitude ranges. As a result the maturity and eventual harvesting cycle is influenced by the climatic environment of those altitude ranges. The result is that the level of uniformity in maturation of the coffee fruit varies according to the influence of the local climatic conditions. It is therefore very common to see fruits at different stage of development on a single branch.

The harvesting process is habitually done with the main selection criteria of fruit colour being the indicator of maturity. As approximately 95 percent of Jamaica’s coffee is Typica the standard colour at maturity is red. However, with the variability in climatic conditions it is sometimes necessary for the harvesters to return to the field a minimum of 12 times for the completion of harvesting.

Altitude
Coffee that is cultivated at very high altitude experiences lower temperatures than that cultivated at lower altitude. In the coffee growing regions of Jamaica the lowest temperatures are normally recorded from December to February. In some years March may also experience low temperatures. In these said areas the hottest months are normally April May, June, July and August, with the rest of the months all experiencing slightly lower temperatures (Met Office 30 year average; 1951-1980).

Temperature
Most of the coffee producing areas of the country have temperatures measuring between 18 to 21°C, which is optimum for coffee cultivation. At temperatures above 24°C, which are mostly on the plains, photosynthetic activity tends to decrease, while at temperatures in the mid thirties(30°C) photosynthesis is almost non existent. For this reason the Jamaican coffee plantations are well managed with appropriate and regulated shade, where this is necessary. The issue of shade management within the Jamaican coffee culture is a critical one. The tropics experience intense solar radiation as the solar rays are very perpendicular to the earth. In the hours of maximum radiation physiological activity is decreased as the leaves close their stomata.

Flowering
In the Jamaican coffee zones the flower process takes place within the warmer months according to the elevation. Within the boundaries of the lowest elevations the major flowering occurs between mid February and Mid March. Within these areas there is a favourable balance of approximately 26/23 °C day/night which, along with the appropriate rainfall, is adequate to stimulate the process. At the mid range elevation a day/night temperature balance of 24/19 °C along with the appropriate rainfall is satisfactory to influence the flowering process. This takes place within the months of April to May. At the high range elevation level the appropriate balance of 22/15 °C along with the appropriate rainfall stimulate the flowering process between the months of August and September.

Fruit development-Phase 1
After the flowering process the first phase is fruit development, which could occur between four and seven weeks after flowering. This is facilitated by a general dry period for most areas, although May and June are regarded as months for high rainfall. This is the period of fruit development in which little growth and weight development occur.

Fruit development-Phase 2
The second phase of development sees rapid development in dry weight and volume.
A high supply of water is essential during this period as this is the time when the bean size expands and become hardened. Therefore, the bean size acquired is dependent on the amount of rainfall experience during this period. Because most areas within the Jamaican coffee zones experience high rainfall for most of this period it partially explains the generally large bean size of our product.

Jamaica’s coffee is carefully hand picked when fully mature. The cherry ripe coffee is then delivered to the wet mill within 24 hours where it is processed, dried (mostly by sun), cured, sorted, packaged and shipped in a manner that preserve the intrinsic qualities obtained from the rich Jamaican environment.

Дата добавления: 2015-10-26