This investigation was carried out at the experimental farm, Faculty of Agriculture, Zagazig University through the growing summer season of 2019. This study was conducted to evaluate the effect of inorganic, organic and bio-fertilization on plant growth and NPK content by successive four cuts of sudan grass plants grown in clayey soils. The most important findings could be summarized as follows: Generally, in most cases, adding any organic sources i.e., chicken manure (CM) or rabbit manure (RM) or Quail manure (QM) or farmyard manure (FYM) at the rate of 0.5% with50 % RD (NPK) plus inoculated by microbien (Mic.) gave the highest significant values of four cuts and accumulative fresh weight as well as N, P and K percentage of sudan grass grown in clay soil compared with control treatment. As a general view, the fresh weight and N percentage of sudan grass grown in clay soil was increased from 1^st cut to 2^nd one then decreased in 3^rd cut followed by last one using the control treatment or 100% RD (NPK) with or without microbien inoculated or 50% RD (NPK) with CM, QM, RM and FYM with microbien inoculated. The same trend was noticed for P% using the microbien inoculated with 50 % RD (NPK) or 50% RD (NPK) alone or control treatment.  Also, the fresh weight of sudan grass was increased from 1st cut to 2nd one followed by 3rd cut then decreased in last one by adding the treatment of 50% RD (NPK) with QM or CM. Similar trend was obtained for N% by adding the 100% RD (NPK) with or without microbien inoculated or 50% RD (NPK) with Mic. The same trend was noticed for P% by adding 50% RD (NPK) plus 0.5% of any organic wastes with or without microbien inoculated. Similar trend was obtained for K% by adding 50% RD (NPK) plus 0.5% of any organic wastes with microbien inoculated compared with control treatment. In general, it could be stated that to increase forage production and its quality of sudan grass, mineral with organic and bio-fertilizer can be used at rate of 50% NPK mineral fertilizers with any organic wastes plus bio- fertilizer (microbien)under the same soil conditions.