A field experiment was performed in a newly reclaimed salt affected soils area of Gelbana village No 7, Sahl El-Tina, North Sinai Governorate, Egypt, during the summer season of 2013, to assess the effectiveness of cyanobacteria as a biological soil conditioner combined with different nitrogen forms and rates to improve and enhance maize production under saline soil. Three N-mineral forms namely N1: urea (46% N), N2: ammonium nitrate (33.5%N) or N3: ammonium sulfate (20.6%N), were added at a rate of 100% or 75% from the recommended dose (RD) (120 kg N/fed) as soil application in presence or absence of cyanobacteria. Maize (Zea mays L., Th. 321 cv.) as a moderately salt-sensitive plant was used as an indicator to identify the response to applied treatments in a split - split plot design.
Results revealed that cyanobacteria application recorded significant increases of plant growth, biological yield and yield components of maize. Under the experiment condition, the results clearly indicated that the applied ammonium sulfate was more effective compared to the other used forms on above mention traits. Moreover, the highest value of N use efficiency (NUE) (79.8%) was recorded in the presence of cyanobacteria combined with ammonium sulfate at a rate of 75 % RD. These results were explained that cyanobacteria could supplement up to 20% of RD of mineral nitrogen fertilizer for maize cultivation in saline soils, this percentage was different from one N form to another. Thus, cyanobacteria currently seem to be offering a potentially environmental friendly alternative to the use of mineral fertilizers, and they succeeded to minimize the amount of applied mineral fertilizer and reduce the production costs and environmental pollution. Furthermore, cyanobacteria application practices as a bio-fertilizer and a soil bio-conditioner alleviated of salt hazards, which improved and enhanced some soil properties reflected positively on maize yield production.