Effect of straw checkerboard barriers method on physicochemical properties of soil and dust reduction in lands exposed to wind erosion of “Margh” meadow of Shahrekord

Wind erosion is a serious problem in arid and semi-arid area. In order to control wind erosion , some technical measures should be focused on the soil surface. Straw checkerboard barrier method as a cheap, effective and easy technology plays an important role in trapping dust and reducing wind erosion. Therefore, the objective of this research was to study the effect of straw checkerboard barriers method on physicochemical properties of soil and probable reduction of dust in lands exposed to wind erosion of Shahrekord meadow.

Straw checkerboard barriers were arranged in 1 m × 1 m checkerboard pattern in January, 2018 in a part of the “Margh” meadow of Shahrekord, the capital of Chaharmahal and Bakhtiari province. Rice straw materials were buried in the soil to a depth of 15 cm horizontally and protruded 20 cm above the soil surface. The study was carried out on a 20 × 25 m land area. The same area was also dedicated for control as bare ground. In order to determine the role of this technique on the wind erosion and its control, vertical sediment traps with a circular cross section of PVC pipe (PVC), 5 sediment traps were randomly installed in the bare ground, 5 in the first area of the checkered barrier, 5 in the middle and 5 at the end of the barrier in the direction of the prevailing wind. Sampling began in late July and was performed every 30 days in five stages. The height of the trap was divided into four parts: 0-12, 12-24, 36-24 and 48-36 cm and the amounts of sediments collected in the installed traps were compared with each other. Wind speed and direction were also measured in the mentioned months and the wind rose was drawn subsequently. Data were analyzed in RCBD design with 5 replications. Sediment trap position was considered as the first factor in three levels and trap height class were considered as the second factor. Also, during two consecutive years after the establishment of straw checkerboard barriers, soil properties including aggregate stability, percentage of clay, silt and sand, organic carbon, total nitrogen, available phosphorus were measured.

Results showed that checkerboards reduced the amounts of sediments significantly. This trend was observed in the five sampling month especially for the traps at the end of the barriers. The wind speed in the collision of barriers decreased significantly with lower amounts of energy, resulted to lowest amount of sediment at the end of barriers. Amount of sediments in the first, middle and end area of the checkerboard barriers in July, August, September and October decreased with the height of the trap drawer. But in November the sediments increased till height of 24 cm that may be due to higher rates of winds and particle movements. The highest mean weight diameter of aggregates was observed in border of barriers which may be associated with significant increase in organic carbon in the borders. Organic carbon, total nitrogen and available phosphorus contents were affected by straw checkerboard barriers and increased in the borders. Fine particles of soil included silt and clay were increased inside the squares accounts for unloading of particles and or deposition of them from the air.

The establishment of straw checkerboard barriers reduced the amount of wind sediments significantly compared to the bare ground. On the other hand, effective particle stabilization and dust deposition increased in checkerboards. Also checkerboard improved the physicochemical properties and increase some nutrients might promising for better microclimate for plant establishment and growth, leading to biodiversity and sustainability return.