Wind erosion is a natural phenomenon that has been increasing due to anthropogenic activities. Wind erosion has detrimental consequences on the environment, and its prevention is a critical issue in many arid regions of the world. The topic of this study was an artificial formation of biocrusts to diminish wind erosion by inoculation of the aeolian sand by two filamentous cyanobacteria of Nostoc punctiforme and Microcoleus vaginatus. The erodibility of the sand was examined in a wind–tunnel equipped with a sand particle counter (SPC). The erosion rate, number of emitted particles, and flux of eroded mass from the surface of the sand were measured as indicators of the erodibility at five wind velocities of 6, 10, 15, 20, and 25 m/s. Results suggested that biocrust of M. vaginatus had thicker interparticle bonding and more resistance than biocrust of N. punctiforme against wind erosion; however, both of cyanobacterial crust reduced the erodibility indicators by two to three orders of magnitude.

No abstract

No abstract

Crusts play a crucial role in the reduction or control of wind erosion. In this regard, the resilience and durability of crusts are of prime importance. Crusts have high resilience and durability against wind flow shear stresses; however, they are prone to abrasion induced by saltating particles. Therefore, estimating crust durability in abrasion rupture has practical importance. In this study, a cyanocrust and a biocemented sand crust were subjected to a controlled flux of saltating particles for different sandblasting periods to provide a framework for predicting crust rupture. The velocity and pre-and post-collision energy of the saltating particles were measured using high-speed photography. The changes in the strength of the crusts after different periods of sandblasting were determined using a scratch test. The results suggested that the average strength of the cyanocrust and biocemented sand crust became 0.25 and 0.7 of their corresponding initial values after 30 min of sandblasting. Also, the average stiffness of the cyanocrust and biocemented sand crust decreased to 0.5 and 0.9 of their initial values, respectively. Furthermore, the amount of impact energy absorbed by the crusts increased by the deterioration of the crusts. Compiling the results of the wind tunnel experiment and scratch tests yielded an exponential equation which can be used to estimate crust durability in a given condition of saltation. Based on this equation, the cyanocrust and biocemented sand crust will break down entirely after 23 and 449 min, respectively, at a wind velocity of 6.8 m/s and a saltation flux of 1 g/s/m.

No abstract