Influence of watering frequency on seedling growth of arabica coffee

Low rate of survival and poor performance of young trees in most newly established coffee stands in Ethiopia may be attributed to the use of poor quality seedlings with undesirable shoot and root growth for field planting. Inadequate or excessive water supply during the nursery period is one of the major factors which account for such undesirable growth of coffee seedlings. This experiment was, therefore, conducted in a conventional coffee nursery at Jima-Melko Research Center to determine the optimum frequency of watering that help produce vigorous and high quality seedlings for transplanting. The design was randomized complete block with three replications. Five-month-old coffee seedlings of cultivar 7454 were subjected to seven watering frequencies, which were applied to replenish to the field capacity of the rooting medium at four-, eight-, 12-, 16-, 20-, 24- and 28-day intervals, and to a check plot (dry treatment) receiving no water until the stage of field transplanting. Results of the experiment indicated that differences among the plots were highly significant for almost all shoot and root growth parameters. Maximum values for stem, branch, leaf and root extension growth, total dry matter yield, and relative water content of the seedlings resulted from more frequent irrigations (applied at four-day intervals, followed by watering every eight days), and the values were lowest for unirrigated or less frequently watered plots. The root to shoot ratio, which is commonly used as an index of subsequent growth and productivity, however, linearly decreased with increase in watering frequency. It was concluded that the performance of coffee seedlings could be improved by applying sufficient amount of water but less frequently, probably at 12- to 20-day intervals under optimum nursery management regimes, expecially after the stage of two to four pairs of true leaves. However, more frequent watering could be advantageous at the early stages of growth.