Document Type : Research Paper
Authors
1 M.Sc. student, Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Iran
2 Associate Professor, Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Iran
3 Assistant Professor, Department of Soil Science, College of Agriculture, Shahid Bahonar University of Kerman, Iran
Abstract
Cyanobacteria play an important role in providing biological soil crusts in sandy soil of desert areas. The aims of the present research are to investigate the possibility of crust formation under three cyanobacteria (Nostoc. sp (N), Phormidium.sp (Ph) and combination of two genus (Ph + N), two polymer treatments [blank (S0) and 0.3 g per 250 g soil (S1)] and two moisture levels [FC (M1) and 80% FC (M2)] in three separated parts. Crust thickness, increase in soil organic carbon and resistance to penetration of crusts after complete coating (60 days) were measured in the first part of the experiment. Then the effects of time (15, 30, 45 and 60 days) on crust thickness and micromorphological investigations of crusts were performed in the second and third parts of the experiment respectively. Results of the study showed that simultaneous application of two genus at FC level with polymer creates the thickest (6.83 mm) and the most resistant crusts (0.27 MPa) to penetration. Both cyanobacteria genus with polymer and FC level caused the highest organic carbon contents (1.89% and 1.66% respectively). Also the thickest crust (6.8 mm) was formed by simultaneous application of two genus during 60 days. Micromorphological observation showed decrease in macro pores in treated samples compared to control and this decrease of pore space size with application of both cyanobacteria genus was higher than each of them alone.
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