The present investigation was carried out in two consecutive seasons (2022 and 2023) on eight-year-old olive trees “Picual” cv., planted at 4×6m apart around (420 trees / Fed). Trees irrigated with drip irrigation system, at a private orchard. The experiment included 3 rates of Feldspar as source of naturel potassium at 2, 4, and 6 kg/ tree and potassium dissolving bacteria as liquid Bio-fertilizers supplemented (25 ml) at two or three times to investigate the yield and fruit quality of Picual olive trees. Data indicated that the yield of Picual olive trees fertilized with feldspar and liquid Bio-fertilizer increase to 70% over control. Picual olive trees treated with (4 kg Feldspar + 25 ml liquid Bio-fertilizer at three doses) achieved the highest increase in the yield for the both seasons and also gave the highest fruit weight, volume and fruit flesh/stone ratio of olive trees Picual cv. Concerning leaf nitrogen percentage (N%) The highest percentage of N% for the both years was recorded by treatment (6 kg Feldspar + 25 ml liquid Bio-fertilizer at three doses). With respect to leaf phosphor and potassium percentage, it could be seen that most treatments gave more or less results similar to the control.