No abstract

Two field experiments were carried out on a sandy soil at Ismailia Agricultural Research Station located at 30º 35´ 41.901˝ N for Latitude and 32º 16´ 45.834˝ E for Longitude, Egypt, during two winter seasons of 2013/14 and 2014/15, to study the effect of inoculation with diazotrophs (Herbaspirillum sp., Azorhizobium caulinodans and Azospirillum brasilense) applied as a single treatment and\or as a mixture treatments under different levels of nitrogen, i.e., zero, 25, 50, 75 and 100 kg N/fed on the growth, yield and some yield components of wheat crop. Obtained results showed that there were significant increases in all wheat vegetative growth characters, yield and some yield components due to inoculation with any tested diaztotrophs. However, using mixture strains followed by Azospirillum brasilense surpassed other inoculated treatments or uninoculated one. Generally, all the inoculated treatments were the superior to in enhancing all wheat growth parameters, wheat yield and its components in the order of mixture> Azospirillum brasilense> Herbaspirillum sp.> Azorhizobium caulinodans> uninoculated.All wheat growth characters yield and its components increased significantly along with increasing N-fertilizer level. Due to the interaction between inoculation and N-fertilizer levels, the splendid results of wheat growth parameters, yield and its components were for wheat plants inoculated with the bacterial mixture inoculum followed by Azospirillum brasilense in combination with 50 kg N/fed, which showed significantly a positive response and gave values nearly similar to or higher than those given by the use of full N-fertilizer level (100 kg N/fed). It is of worth to note that inoculation with diazotrophs having excellent potential to be used with non-legumes not only because of their N 2 -fixing proficiency but also to their ability to acts as PGPR. The triple diazotrophs treatment may be acting as a good practice for sustaining wheat grain yield and reduce the reliance on chemical fertilizers in agriculture, to minimize the environmental pollution and to have safe healthy food.