Nelvia2014-02-032014-02-032014-02-030825-0585wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/5454The peat soiL taken from Rimbo Panjang, Kampar Riau with saprik. The research is conducted experimentty and uses factorial complete random design which contain of 2 factors: application of oil palm bunch ash ln 4 levels (0, 300, 600 dan 900 kg/ha) and K fertilizer in also 4 levels: (0, 36, 72 dan 108kg K2 O/ha). Result of theresearch indicates that oil palm bunch ash can substitute K around 36 Kg k2 o/ha. The applied of 300 kg/ha of oil palm bunch ash without K fertilizer can increase height of plant, but it does not influence an amount and weigth of leaves even though K dosage (K fertilizer and oil palm bunch ash) is increased. The applied of 600 kg/ha of oil palm bunch ash can increase melon fruit diameter and weight about 13,11% and 32,57% if it is compared to control.enpeat soilK fertilizeroil palm bunch ashUR-Scientific Work Lecturer