Effect of Blue-Green Algae in Soils with Different Texture: (b) on Microbial Communities of Soils

Abstract

Applicability of cyanobacteria strains (Nostoc lichenoides, Nostoc indistinguendun, Nostoc favosum) and their mixture for effect on microbial communities of soil under four levels of inorganic nitrogen (0, 20, 40 and 60% N) was used with recommended doses of nitrogen (70 kg N fed -1 ). This experiment was carried out in two types of soil texture (sandy and clay loam) to enumerate the number of viable bacteria, azotobacter, actinomycetes, and fungi. Results indicated that the cyanobacterial strains varied significantly and pronounced an increase in all microbes. So, the sandy soil count was lower than clay loam soil. The treatment with Nostoc favosum recorded the highest total counts of bacteria (270.9 ×10 6 CFU/g dry soil) compared to those found by the other strains of tested cyanobacteria. The addition of cyanobacteria to the sandy soil increased the number of Azotobacter, and the best number of azotobacter in the mixture was (52.3×10 3 CFU/g dry soil) compared to uninoculated (20.5×10 3 CFU/g dry soil). However, inoculating two soil types with the mixture of cyanobacterial strains gave the highest Actinomycetes counts compared with individual strain. Also, the treatment of types soil with the mixture of cyanobacterial strains gave the highest counts of fungi compared with any other inoculated. The inoculation with other cyanobacteria strains and their mixture increased the soil microbial population including, total counts of bacteria, Azotobacter, Actinomycetes, and fungi.