Spray tank additives were used with glyphosate (IPA) through multi mixtures to increase its biological performance against intractable weeds in olive orchard. In addition to assessed the role of its combination on amino acids metabolism and soil microorganisms under greenhouse conditions. Cynodon dactylon, Mesmbrayanthemum crystallinum and Solanum elaeagnifolium are the dominant weed species respectively in olive orchard at north Sinai, El Arish, Egypt. Total weed frequency was affected greatly by glyphosate at micro rate 2.0 kg active ingredient ha^-1 plus additives as compared with glyphosate at full rate 2.2 kg ai ha^-1 without additives. An equal reduction in tyrosine aromatic amino acid was recorded after treated nutsedge leaves with glyphosate at full rate and glyphosate at micro rate with its additive mixture by 100%, also using additives increasing the level of reduction of phenylalanine acid when applying T₄ (Glyphosate at 2.0 ai ha^{-1 +} glue + dioleate)_, T₅  (Glyphosate at 2.0 ai ha^-1 + glue + glycerin)andT6 ₍Glyphosate at 2.0 ai ha^{-1 +} glue +glycerin + dioleate) decreased phenylalanine acid reached, 85.05, 85.05and 89.655%, respectively as compared with the control (3 weak after treatment). Application of glyphosate at 2.2 kg ai ha^-1 alone or at 2.0 kg ai ha^-1 with some mixtures additives slightly affected total count of bacteria and spore forming fungi at 10 days after treatment (DAT) and caused slightly observed temporary effect in bacteria count at zero time to 10 days as compared with control. Adding glycerin as non ionic surfactant to glyphosate in the spray tank with other  additives caused observed effect on total microbial count compared with others additive did not contain glycerin.  The best control regime obtained when glyphosate at micro rate mixed with  glue + dioleate (T₄) was applying  at  C.dactylon andC.rotundus and other annual weeds which have slightly  effect on soil microorganisms  was count, However the combination of glyphosate at micro rate +glue +glycerin + monoleate (T₇) was more suitable to intractable weedssuch as S. elaeagnifolium and M.crystallinum with slightly effect on soil microorganism, Therefore, the improvement in glyphosate bio efficacy depends on additive types and weed species.