User:Raf Aerts/Notebook/Open Coffee/2008/09/02
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Field notes on traditional coffee management (agobado)
Coffee plants form vertical, orthotropic shoots, and horizontal, plagiotropic shoots. Coffea arabica berries are produced at the end of the plagiotropic shoots, whereas C. robusta forms berries on mature material of plagiotropic twigs. Rejuvenation of shoots at the level of individual shrubs and shrubs at the level of the stand are therefore the two fundamental principles of Arabica coffee shrub management.
Old coffee plants (7–10 years old) are either replaced, or coppiced. A shrub will typically remain unproductive for 2–3 years after complete stumping, but nonetheless, it forms the basis of the local coffee pruning or agobado system, which aims to maximize the number of fruiting shoots on each coffee shrub. The agobado system consists of an ingenious sucker bending system. After stumping, 3–4 suckers are allowed to grow (the rest of the sprouts is removed). When the suckers are ~2 m tall, they are bent towards the ground (giving each sucker a starting angle of 45°). On these bent suckers, secondary orthotropic (vertical) shoots will develop and these, in turn, will produce tertiary, plagiotropic (horizontal) and thus fruiting shoots (Fig. 1). By bending the suckers, the production of berries is delayed from secondary to tertiary shoots, hereby increasing the number and the cumulative length of productive shoots and thus, yield. Normal yield is about 1 ton ha-1 year-1; higher yields can be obtained by reducing the shade (coffee leaves become brighter), but these plants will loose productivity sooner.
Fig. 1 (link to high resolution version Media:coffea.tif)