Review of Arabica Coffee Management Research in Ethiopia

Abstract

Coffee seeds with moisture content grater than 40% when stored in moisture vapor barrier containers, viz. glass jar and polythene bag had retained their viability and vigor for a longer period. However, sowing coffee seeds immediately after harvesting and processing was found to be the best option for higher germination rate and better seedling growth. Pre-germination is the primary cause of multiple and crooked tap roots and eventual tree death in the field. Forest soil or a mixture of top soils (TS), compost and sand (S) in 3 : 1: 0 and 2 : 1 : 1 ratios or blends of organic manure and TS in 1 : 4, 2 : 4 and 3 : 4 ratios resulted vigorous seedling growth. Applying 750 mg P or a combination of 2.31 g lime and 250 mg P pot^-1 (2.5 kg sieved TS) ensured production of quality seedlings. Sowing coffee seeds at a depth of 1 cm with the grooved side placed down and embryo tip up had improved germination. Seedbeds covered with 3 - 5 cm thick mulch after seed sowing and watered at 2 days interval until hypocotyl emergence had higher germination percentage. After emergence, with the removal of mulch, nursery beds provided with 50% over head shade and irrigated twice a week until seedlings attained 2 to 4 pairs of leaves and then after at  a week interval produced vigorous seedlings. Sowing clean coffee seeds after soaking in cold water for 24 hours hastened germination and seedling growth. Soft wood single node cuttings with one pair of leaves and blends of TS, S, and manure in 2 : 2 : 1 ratio was recommended for vegetative propagation of hybrid coffee. Rrejuvenation practices, viz. topping, agobiado and eskeletamento increase forest coffee yield by 43.2, 40.4 and 38.0% over clean stumping and 12.5, 8.4 and 4.7% over control (not rejuvenated trees), respectively. Earlier stumping immediately after harvesting tends to promote yield. Coffee trees stumped at 50 cm height had slightly higher yield than the conventional 30 cm stump. Tied ridge gave respective yield advantage of 19.0 and 23.6% over untied ridge and traditional flat land field. Maintaining 3 - 4 bearing heads per tree or stump and adjusting plant population to 4000 - 5000, 5000 - 6000 and 7000 - 8000 trees ha^-1 had maximized productivity of forest coffee at Tepi, Jima and Metu and Agaro, respectively. On the other hand, forest coffee stands did not respond to mineral fertilizer application and weed management. Deeper and wider hole size and transplanting July/August increased field survival rate of coffee seedlings. Tractor and oxen cultivation, planting coffee seedlings 10 cm deeper than the collar level and ball root transplanting mehod had significantly improved early growth performance and survival rate of of the plants. Millettia ferruginea, Albizia spp. and Acacia abyssinica, Erythrina abyssinca, Calpurnea subdecondra and Cordia africana shade trees promoted coffee yield especially when strip planted with coffee trees. Based on the canopy architecture three distinct morphological classes (open, intermediate and compact) Araabica coffee types are identified. High density planting increased coffee yield especially in the open sun fields; however its efficiency has been found to vary depending on the canopy nature of coffee plant and agro-ecological condition of the area. The use of locally available and cheap organic fertilizer sources such as coffee husk and manure as complements to mineral fertilizer was found to be very important for sustainable soil fertility amendment and promotion of organic coffee production. Intercropping did not significantly affect growth and development of coffee trees when planted in proper combinations. Among coffee cultivars, the compact types were more suitable for intercropping than the intermediate and open coffee type to sustain crop yields. Moreover, higher yield advantage was obtained from intercropped plots as compared to sole stands. This was particularly noticed for annual crops at early stage and with lower coffee population and decreased with increasing years of coffee production. Similarly, the gross monetary benefits were greater due to intercropping coffee with potato, turmeric and ginge than for sole coffee plots. In general intercropping coffee with locally adapted and compatible cash and food crops is agronomically beneficial and economically feasible in south and southwest Ethiopia.

Keywords: Arabica coffee, coffee seed,  forest coffee, intercropping, plantation coffee