Effect of fertilization on yield and quality of Arabica coffee grown on mountain terraces in southwestern Saudi Arabia

Abstract

Coffee, Coffea arabica L., is the most commercially important species of the genus Coffea. It has been grown on the mountain terraces of southwestern Saudi Arabia for centuries. Orchard productivity is generally low due to reduced fruit set and yield caused by the limited use of fertilizers and recurring droughts. The current study was carried out to determine if the coffee trees grown in typical Jazan coffee gardens would respond positively to increased input of fertilizers. The treatments were either 0, 455, 910, or 1365 g tree−1 year−1 of a complete fertilizer mix. The trees also received 2 kg of compost. The yield, cherry fresh weight, bean dry weight and flower density were measured over two consecutive growing seasons. The yield was not significantly changed by fertilization in the first year but was improved in the second year with the trees that received the full dose of fertilizer giving twice as much fruit as the control trees due to higher flower and fruit densities and cherry mass. The application of fertilizer increased cherry fresh mass in both years and tended to increase bean dry mass. The trees that received one dose or 1.5 dose of fertilizer produced a higher proportion of beans of the larger size. Using fertilizers increased tree yield and improved bean size potentially improving farm-gate prices of the crop. The increase in the estimated value of the crop more than covered the cost of fertilization. More trials are needed to determine the effect of fertilization combined with other cultural practices such as drip irrigation, tree pruning and improved pest control on yield, bean quality and liquor taste.