Inorganic Fertilizers Requirement of Coffee (Coffea arabica L)--) Review

Arabica coffee (coffea Arabica L), is indigenous still grows wild in the forests of south-western Ethiopia, which remains an important source of genetic resources for the world coffee industry. It is one of the stimulating crops widely drunk in the world next to tea , contributes to more than 50-60% of the Ethiopia’s foreign earning and with 44% of all production consumed domestically. In Ethiopia, most soils are exposed to nutrient leaching over a long period resulting in low organic matter content and require careful management to support good crop yields. However, 85% of Ethiopian farmers don’t use organic fertilizers while the rest add it at levels significantly below the recommended rate. The bulk of coffee soils in the south western region are classified at nitosoils, which are highly weathered and originate from volcanic rock. These soils are deep and well drained having a PH of 5-6, and have medium to high contents of most of the essential elements except nitrogen and phosphorous. The importance of proper coffee nutrition cannot be over emphasized because nutrition affects bean size and bean quality, both of which determine the value of the coffee produced. It is worth remembering that for optimum growth and productivity, the coffee plant requires adequate nutrients. Nutrients are applied to replenish those that are lost through tissue formation, yields, leaching and those that form compounds where they cannot be easily extracted by roots. This calls for application of fertilizers so as to apply the necessary nutrients in the required .amounts. When fertilizing coffee trees, two distinct aspects should be considered: The compensation of the actual deficiencies, the necessary inputs to replace depletion caused by the coffee trees themselves and by lixiviation. Fertilization should also provide for the needs of the various microorganisms which play an active part in the quality of the topsoil. Replacing mineral depletion in the topsoil and neutralizing the effects of toxic elements are basic prerequisites to ensure production & Coffee quality in the coffee plantation. Therefore the objective of this paper is to review various investigations of coffee inorganic nutrient requirement & its influence on growth, yield and quality. A balanced fertilization of all major and minor nutrients will result in two important functions, namely production of good crops and also production of fresh cropping wood frame work for the succeeding year. Coffee plants have high N and K requirements Coffee has a very high demand for nutrients and takes up huge quantities from the soil. It has been estimated that a hectare of fast- growing highly-yielding coffee takes up an annual total of about 135kg N, 34kg P2O5, and 145kg k2O. Laves need the major part of the uptake - more than the flowers or fruits. The results reported show significant coffee yield increment with increasing level of nitrogen. Significant yield improvement was reported in response to the interaction between nitrogen and phosphorus fertilizers. Several studies have been reported that Phosphorus is known to be one of the most recognized limiting factors for coffee production in most soils of south-western Ethiopia..The study indicated that the highest available P content in the soil was found 80 days after application at a distance of 45cm from the trunk and 15cm depth. Results from some trials involving potassium fertilizer also indicate positive crop responses to potassium application. Fertilizer application & recommendation depends on various factors including: type of production system , soil fertility status and soil reaction, type of coffee variety, age of the coffee tree and plant population. Too much & little fertilizer in the plant will reduce cup quality. Younger leaves have higher alkaloid contents than older leaves & statistically similar to the control treatment, omission of K encourages the greatest increase (12%) of caffeine contents in leaves. The nutrient status of most soils is expected to change after a long period, varieties released and new for users might have different response or requirement to mineral nutrition. Therefore, fertilizer recommendations have been carried out should be updated ted Keywords: Coffee, Inorganic fertilizer, N, P , K application