Maximizing Use Efficiency of Mineral Fertilizers Using K Fulvate and Azotobacter chroococcum DSM 2286 and Their Effect on Wheat Production and Nutrients Uptake.

Increasing the yield of wheat (Triticum aestivum L.) is an important national goal to meet the everincreasing food needs of the Egyptian population. Wheat is one of the three major kinds of cereal crops (along with maize and rice). Also, it is a main source of energy, renewable resources for food, feed and industrial raw materials, the source of protein and fiber in the human diet, and staple food crops for more than a third of the world's population (Ramadoss et al., 2013) grown as a spring and winter crop. Zaman et al. (2010) found that, the use of synthetic fertilizers is closely related to crop yield. It is evident that only half of the applied nitrogen fertilizers are taken by the crops and the second half are lostfrom the agricultural field through surface runoff and leaching of nitrate as well as volatilization of ammonia and emission of NO x gases (Gogoi and Baruah, 2012). For these reasons, great attention needs to be paid to finding a new type of fertilizer that, ideally, can be low cost with high nitrogen utilization efficiency (Chander, 2012). D two successive growing winter seasons (2016/2017and 2017/2018) at the experimental farm of Meet Ghamr, Dakahlia Governorate, Egypt. A field experiment was carried out to maximizing use efficiency of mineral fertilizers (N, P and K) by application of potassium fulvate (KF) and bio-fertilization (Azotobacter chroococcum DSM 2286) on growth, yield and some chemical compositionsof wheat plant (Triticum aestivum L.) variety Giza 171. The layout of the experiment was a splitplot design, with the main plots arranged in a randomized complete blocks design, with three replicates. This experiment includes three main treatments and four sub-main treatments. Where the three levels of mineral fertilization “NPK” (60, 80 and 100% of the recommended mineral fertilization) were assigned in the main plots. On the other hand, the application of potassium fulvate and biofertilization were assigned in the sub-main plots. After 75 days from sowing, fresh and dry matter yields, chlorophyll (a, b and a+b), carotenoids in leaves, dehydrogenase activity in rhizospheric soil and the N, P, K, Fe, Mn and Zn in shoots of wheat plants were determined. As well as at harvest stage, weight of 1000 grain (g), yields of straw and grains (ton ha), and their content of N, P, K, Fe, Mn and Zn were determined. The obtained results indicated that, the application of KF and Azotobacter chroococcum alone or in a combination resulted in a significant increase in all studied parameters compared to the control. Under 80 % of the recommended mineral fertilization (N, P and K), the dual application of KF + Azotobacter chroococcum showed a significant augmentation in all studied parameters compared to the control under 60, 80 and 100 % of the recommended mineral fertilization. Therefore, it considered as a more beneficial treatment in the cultivation of wheat plants (Giza 171 variety) at Nile Delta due to it resulted in a high yield, quality and reducing the environmental pollution as a result from reducing the additions of the mineral fertilizer with the organic and the biofertilization one.