Soil mechanical properties and wind erosion following conversion of desert to irrigated croplands in central Iran

Abstract Conversion of the virgin desert to agricultural lands can obviously alter some soil properties; however, little is known about how this conversion impacts soil mechanical properties and wind erosion. The present study therefore aimed at assessing the impacts of agricultural exploitation on aggregate stability, mechanical properties and wind erosion of desert soils in Abarkooh plain, central Iran. To do so, three land uses were assessed: (1) wheat (Triticum aestivum L.), (2) pistachio (Pistacia vera L.), and (3) the adjacent virgin desert soils. Ten sites including three land uses were selected. At the time of soil sampling, the vane shear test was performed. Then, the composite soil samples (0–20 cm depth) were taken for laboratory analyses. Soil organic carbon, bulk density, mean weight diameter, wind erosion rate, wind erodible fraction, shear strength value, cohesion (c), and angle of internal friction (φ) were measured. The results showed that soil organic carbon content in the croplands was greater than that of desert. Nevertheless, according to findings, soil gravel, electrical conductivity, and bulk density decreased with cultivation. Compared to the desert (0.21 mm), wheat (1.71 mm) and pistachio (1.34 mm) fields had a higher dry mean weight diameter of soil. The wind erosion rate in the desert (1.48 g m−2 s−1) was 16.4 and 13.5 times greater than those of wheat and pistachio fields, respectively. Also, the wind erodible fraction in the desert was significantly higher (85%) compared to the cultivated soils (52–58%). The value of φ was greater in wheat‒cropped soil (41.05°) than in the desert (36.90°). The c values (21.39–22.46 kPa), vane shear strength (14.36–14.78 kPa) and shear strength values (22.14–23.49 kPa) in the croplands were 5.2–5.4, 5.0–5.1, and 4.9–5.2 times greater than those of desert, respectively. These results revealed that sustainable use of irrigated desert lands could be an appropriate method which significantly improves soil mechanical resistance against wind erosion.