Sand transport is the main manifestation of sand damage in the arid and semiarid regions globally. It is a huge challenge to stabilize mobile sandy and change them into stable productive ecosystems. The establishment of simulated shrubs is one of the most effective measures to solve the above difficulties as a novel sand-barrier. To clarify simulated shrubs’ role in the process of ecological restoration. It will be greatly helpful to incorporate the shelter device proposed in the present work into landscape models for aeolian soil transport, to optimize the parameters associated with the sand-barrier characteristics for aeolian soil stabilization at the field scale. A series of wind tunnel experiments were conducted to analyze the variations of soil grain-size of simulated shrubs with different spatial configurations, row spaces, and net wind speeds. Further, the soil grain-size parameters were calculated by the classic method proposed by Folk and Ward to clarify the change of soil particles resulted from the blocking effects. The average grain-size content of simulated shrubs with different spatial configurations, row spaces, and net wind speeds was dominated by medium sand and fine sand, and the total percentage was more than 90%. Moreover, the sand deposition of simulated shrubs with different spatial configurations increased with the improvement of wind speeds. The average sand deposition of spindle-shaped simulated shrubs in 17.5 × 17.5 cm and broom-shaped simulated shrubs in 17.5 × 26.25 cm under different net wind speeds was the least. The effects of row spaces on average grain-size parameters increased with the improvement of net wind speeds. By calculating the correct characteristics of specific shelter devices proposed in the present work, all of these findings suggest that the application of simulated shrubs will be an important component to further extend ecological engineering projects in arid and semiarid regions.

Wind erosion has gained increasing attention as one of the most serious global ecological and environmental threats. Windbreaks are effective at decreasing wind erosion by reducing wind speed to protect crops, livestock, and farmsteads, while providing wildlife habitats. Synthetic shrubs can act as novel windbreaks; however, there is limited knowledge on how their design affects wind speed. This study determined the protective effects (airflow field and sheltering efficiency) based on the design of synthetic shrubs in a wind tunnel. Broom-shaped synthetic shrubs weakened the wind speeds mainly at the middle and upper parts of the shrubs (5–14 cm), while for hemisphere-shaped shrubs this effect was greatest near their bases (below 4 cm) and least in the middle and upper parts (7–14 cm). Spindle-shaped synthetic shrubs provided the best reduction effect in wind range and strength. Moreover, the wind speed reduction ratio decreased with improved wind speeds and ranged from 26.25 cm (between the second and third rows) to 52.5 cm (after the third row). These results provide strong evidence that synthetic shrubs should be considered to decrease wind speed and prevent wind erosion.

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Wind erosion is a huge challenge for ecologists to stabilize sand dunes and to change them into stable productive ecosystems. In order to better understand its role in the process of ecological restoration, the sediment grain-size characteristics of compound sand barrier were evaluated through field experimental observation. The results indicated that the compound sand barrier was mainly composed of extremely fine sand and fine sand, and the fine sand and extremely fine sand in the inner side were higher than the east and west sides of the compound sand barrier. Due to the blocking effect of compound sand barrier, the Sorting Coefficient became better, the Skewness belonged to the positive deviation and the Kurtosis presented leptokurtosis distribution. Moreover, while the cumulative frequency distribution curve in the inner side became steeper, the slope increased and reached the top of the curve ahead of time. The effect of wind environment and vegetation coverage on the surface sediments showed that the average annual wind velocity and vegetation coverage was negatively correlated with the average grain-size, but positively correlated with the Sorting Coefficient. There was a significant correlation among the annual wind speed, vegetation coverage, average grain-size and Sorting Coefficient, which indicated that vegetation coverage and wind environment was the key factor leading to the difference of surface sediments in this area. Collectively, the establishment of compound sand barrier is one of the most effective methods of sand-fixing with engineering measure in the arid desert regions. Therefore, given the complexities of agricultural systems, stubble retention and black film covered during harvesting and incorporation of the stubble into soil in the next spring appears to be the best choice in the dry northern China where farmlands suffer serious wind erosion. China is one of the countries most affected by desertification. Since the early 1950s, more than 70 serious sandstorms have occurred, which have caused huge losses to human life and property, and seriously threatened the living environment of the local people. Sandy desert land cover a 1.49 million km 2 of China, 15.5% of the total area 1,2. Due to sand transport and dune burial on arid desert regions, pipeline corridors, power transmission lines, transportation routes and people exploitation have been damaged. So far, wind erosion is still one of the most serious problems in many agricultural lands 3,4 and it is currently recognized as a major source of environment degradation 5. Consequently, a series of ecological engineering constructions and projects to stabilize sand dunes along highways or railways in desert regions were begun in the 1950s 6,7. The establishment of sand barriers on deserted land has been one of the most popular restoration techniques. It has been widely used in habitat recovery and protection before and after the construction, such as pipeline corridors, transmission lines and transport routes in arid desert areas, as well as...

A better understanding of the distribution of the airflow field and wind velocity around the simulated shrubs is essential to provide optimized design and maximize the windproof efficiency of the wind barriers. In this study, a profiling set of Pitot Tubes were used to measure the airflow field and wind velocity of simulated shrubs by wind tunnel simulation. The effects of form configurations and row spaces of simulated shrubs on windproof effectiveness were in-depth analyzed. We come to the following results: The weakening strength to wind velocities of hemisphere-shaped and broom-shaped shrubs at 26.25 cm was mainly concentrated below 2 cm near the basal and 6-14 cm in the middle-upper part, while the spindle-shaped shrubs were at 0.2-14 cm above the canopy, which meant the windproof effect of spindle-shaped shrubs was better than that of hemisphere-shaped and broom-shaped. With the improvement of row spaces, the weakening height to wind velocities of the hemisphere-shaped shrubs at 35 cm was concentrated below 2 cm except for the 6-14 cm at 26.25 cm. The designed windbreaks with Nitraria tangutorum, which reduced the wind velocity among the windbreaks more effectively compared to behind the windbreaks. In the wind control system of Ulan Buh Desert, the hemisphere-shaped windbreak should be applied as near-surface barriers, and the windbreaks of broom-shaped and spindle-shaped can be used as shelterbelts above the near-surface. These analytical findings can offer theoretical guidelines on how to arrange the wind barriers for preventing wind erosion in the most convenient and efficient ways.