5337 Journal of Applied Sciences Research, 9(8): 5337-5343, 2013 ISSN 1819-544X This is a refereed journal and all articles are professionally screened and reviewed ORIGINAL ARTICLES Corresponding Author: Heba, M.A. Khalil, Soils, Water and Environ. Res. Inst., Ag ric. Res. Center (ARC), Giza, Egypt. E-mail: drhebaabdelaziz@yahoo.com Effect of bio- organic fertilizers on barley plants in a saline soil. Heba, M.A. Khalil, Afifi, M.M.I., El-Akshar, Y.S. and El-Sayed, G.A.M. Soils, Water and Environ. Res. Inst., Ag ric. Res. Center (ARC), Giza, Egypt. ABSTRACT Field experiment was conducted on a farm at South El- Hossinia Res. Farm Station, El-Sharkia Governorate, Agric. Res. Center (ARC), Egypt, during the winter season 2012. The effect of rice straw, humic acid as organic fertilizer and with the inoculation some bacterial strains as biofertilizer (Pseudomonas putida, Bacillus megatherium, Azospirillum brasilense (PGPR)) separately or together in the with or without rice straw on barley plants c.v. Giza 123 grown on a saline soil. Results revealed rice straw treatments enhanced significantly soil organic matter compared with the rest of the transactions under study. Also, all treatments transactions with add of humic acid with PGPR either rice straw or without led to a lower degree of pH and EC of the soil compared with other treatments achieved pH 7.28 to 7.08 and 7.11 to 7.08 while EC was 5.15 to 4.20 and 4.50 to 3.11 dS/m respectively, during period from 50 to 90 day. In addition, PGPR with humic acid (T4 and T8) increased nitrogen content of the soil compared with the rest of the transactions, as well as control. The treatment of spraying mixed of PGPR and humic acid in the presence of rice straw resulted in significant increase for barley crop and N., P. and K. content of the grain and straw comparison with control. Generally, it could be drawn that the use of the treatment of spraying mixed of bacterial strains (PGPR) and humic acid in the presence of rice straw was useful for the barley crop and its cause prevent the deleterious effects of soil salinity stress and enhancement of soil chemical and biological properties. Key words: Barley, biofertilizer, organic fertilizer, Salinity Soil Introduction Increasing soil salinity in Egypt and in many other parts of the world is a serious land degradation issue around the world. Both salinity and sodicity decrease plant productivity and consequently, the contribution of plant biomass carbon to organic carbon content in soil. As a result, salt-affected soils are generally low in organic matter. The addition of organic materials such as farmyard manure, green manure, crop straw or compost is a common practice to alleviate the adverse effects of salinity and sodicity in agro-ecosystems through beneficial physico-chemical changes in salt-affected soils, thereby improving soil productivity (Yadvinder et al. 2005). Salinity and sodicity may alter soil pH and other physicochemical properties, thereby affecting biochemical transformations of added plant and native carbon in soil. Contradictory results of salinity and sodicity stresses on soil biological processes are often reported. For example, many studies reported that salinity decreased and sodicity increased organic carbon mineralization in soil. (Pathak and Rao 1998). In the rhizosphere, the synergism between various bacterial genera, such as between Bacillus, Pseudomonas, and Rhizobium has been demonstrated to promote plant growth and development (Halverson et al., 1993). Mechanisms by which bacteria can promote plant growth include mobilization of nutrients and production of phytohormones (Lugtenberg and Kamilova 2004). The microbial synthesis of plant growth regulators is an important factor in soil fertility. Plant growth -promoting bacteria can prevent the deleterious effects of stressors from the environment (Egamberdieva, 2009). Hasnain and Sabri (1996) reported that inoculation of plants with Pseudomonas sp. stimulated plant growth by reduction of toxic ion uptake and increases in auxin contents. Plant stress can be reduced by 1-aminocyclopropane-carboxylate (ACC) deaminase producing bacteria (Glick et al., 1997). The plant hormone ethylene has previously been found to be an inhibitor of plant root elongation (Abeles et al., 1992), and its production in plants is highly dependent on the endogenous levels of ACC. The ACC deaminase enzyme can cleave the ethylene precursor ACC to α ketobutyrate and ammonium and thereby lower the level of ethylene in developing or stressed plants (Glick et al., 1998). Thus, plant growth-promoting bacteria contain the enzyme ACC deaminase and colonize the seed coat of a developing seedling, and may decrease the ethylene level so that it does not become too high to limit root growth (Hontzeas et al., 2004). Furthermore, by removing ACC, the bacteria reduce the deleterious effect of ethylene, ameliorating plant stress and promoting plant growth (Glick et al., 2007). These bacteria may enhance the survival of some seedlings, especially during the first few days after the seeds are planted. In our previous study,