Abstract

An experiment was conducted on the research farm of Faculty of Agriculture and Food Sciences, Ibb University, Yemen, in 2014-2016 to identify the effect of four levels of potassium fertilizer (48% of potassium sulphate) on Arabica apple coffee, namely T1 (0), T2 (50), T3 (60), and T4 (70) g/tree. Then, 2 kg/tree of an organic fertilizer, and 50g/tree of phosphorous fertilizer were added. The experiment was carried out by using a complete random pieces design (RCBD) with four replicates where each replicate contained 4 trees. Next, the field received a drip irrigation along periods separated by 7 to 12 days.

The findings of the study showed that in June of the first year 2014-2015, there were statistically significant differences at the level (P ≤ 0.05) in lengths between the third treatment and other treatments. In May, there were statistically significant differences in branches between the second treatment and other treatments, showing no significant differences between lengths and branches in the other months. In the second year 2015-2016, there were no statistically significant differences in lengths and branches in July, September, October and February, while there were in branches in August and December between the second and first treatments. In November, January, March, April and May, there were statistically significant differences between the three treatments, and the first treatment (control). In June, there were statistically significant differences between the second and fourth treatments, and the first one. Concerning productivity of trees in the first year, there were statistically significant differences at the level (P ≤ 0.05) between T2, T3 and T4, and the control one. Finally, in the second year, there were statistically significant differences between both T3 and T4, and both second and control treatments, showing that the T4 scored the top rank in productivity (1189 g/tree).