Two field tests done in 2013 and 2014 on two kenaf varieties: Fuhong-952 and 4383 at Universiti Putra Malaysia which was to investigate the fertilizers effect of the protein content in the cell wall of the fibers. Potassium as muriate of potash at the rate of 0, 100 and 150 kg/ha, was added to the plants which was in two different stages of plant age, in each stage added halve dose at planting day and after planting by three weeks. Boron and zinc were also added to the plants, while the second time of potassium application (0, 1.0, 1.5 and 0, 5.0 kg/ha, of borax and zinc chloride), respectively. Besides that, during the second field test FH-952 was selected with applying the highest level of potassium 150 kg/ha, additionally other levels of zinc were added to display its impact of quality properties. The best result of protein content was achieved for FH-952 when potassium was added at the high level, nevertheless 4383 was when potassium, boron and zinc were applied at the rate of 150, 1.0 and 5.0 kg/ha, respectively. During the second experiment zinc performances caused to achieve tough fibers which was possible for using as biocomposite materials.