Results of Crop Improvement and Management Research for 2019/2020 Part II

Abstract

An experiment was conducted to determine the coffee cycle change period in medium and higher agro-ecologies of Jimma and Gera Agricultural Research Center with the objective of identifying coffee tree exhaustion period and indicator parameters to implement the first cycle change period of coffee cultivars. The experiment was super imposed on compact and open varieties with four tree management treatments, which are single stem topped, multiple stem topped, multiple stem un-topped and free growth training and pruning practices, using randomized complete block design with three replications on trees that stayed in the field for fifteen years. In addition to yield this experiment evaluated the raw and cup quality. Results of this study revealed that coffee yield response oscillated for both compact and open varieties at both locations after giving one or two optimum crop across all coffee tree management practices. The overall average crop yield for the last 12 cropping years for all tree management practice were in between 1450 kg/ha to 2450 kg/ha. Four indicator parameters, dead, non-bearing, bearing and new branches are identified to evaluate the coffee tree productive center. Results of evaluation of exhaustion of coffee tree productive center revealed that dead branch part reached at 61% to 75%, the non-bearing branch 3% to 6%, the bearing portion 17% to 28% and the new and future potential branch part 2% to 4% after fifteen years. There is a significant variation on some of the quality parameters among varieties and coffee tree management practices, the raw quality of coffee showed maximum amount of coffee beans under screen no. 16 which is about 55% of the sample coffee bean was medium size. Fewer amounts of coffee beans found from screen no. 20 which is the very large bean size accounted for 1.55% of the total sample. Therefore, coffee trees became exhausted after15 years at medium and higher altitude agro-ecologies like Jimma and Gera, and coffee tree can be more productive only for 12 cropping years if all nursery and field level management practice are intensively applied. As the coffee tree gets older the size of the beans became smaller due to the exhaustion of the source to the sink relationship. In general, when the coffee tree became unproductive up to 70% cycle change is crucial.