The Role of Cyanobacteria Isolated from Khabr National Park Biocrust in Modification of Some Soil Characteristics and its Effect on Secale Montanum Growth

Khabr National Park is one of the valuable natural resources in Iran, and its cyanobacterial population has not been studied yet. Cyanobacteria are the most important nitrogen-fixing bacteria in all aquatic and terrestrial environments, playing a vital role in arid and semi-arid ecosystems. The present study aimed to determine the role of different cyanobacterial species isolated from the grazed and not grazed areas in two cold and warm steppes of Khabr National Park on some soil properties and the effect of the selected cyanobacteria on Secale montanum growth.

In the present study, cyanobacteria were isolated from a harsh terrestrial ecosystem and cultured on a BG11 medium. Next, the expression of the nifH gene was assayed in all nitrogen fixing isolates using the Real Time-PCR. Then, the best nitrogen-fixing cyanobacteria (Nodularia. sp.) was selected and its activity was investigated in pot experiments alone and in combination with chemical fertilizer. Three different soils in terms of physical and chemical properties were analyzed.

The results indicated that the treated soils with Nodularia sp. as a biofertilizer can significantly increase nitrogen content of both agricultural soil and mixed soil. Consequently, Nodularia sp. has the ability to promote some characteristics of the studied soil through improving TN, SOC, SOM, and enzyme activities.

It can be concluded that the selected cyanobacterium increase soil stability in terms of mechanical fracture and resistance to desiccation and improve soil structure, which is very important, especially in arid and desert soil.