Dry and water-stable aggregates in different cultivation systems of arid region soils

Soil aggregate stability has been known as one of the most important soil properties which is influenced by cultivation system. This study investigates the effect of different cultivation systems on aggregate stability indices in two statuses of dry (DSA > 0.25 mm) and wet (WSA > 0.25 mm). The study was done in six cultivation systems consisting wheat, barley, maize, alfalfa, fallow, and plowed farms. The results showed that aggregate stability indices affected significantly by the type of cultivation system. In contrast, no meaningful effect of soil depth (0-10 and 10-20 cm) on selected soil properties was observed. In addition, soil primary particles as well as organic carbon differed significantly between the cultivation systems. Wheat and alfalfa farms consisted of larger aggregates, while water-stable aggregate for wheat found to be in a greater degree. Moreover, wheat and barley showed the highest contents of organic carbon. The results of WSA > 0.25 mm indicated that the correlation coefficients for sand, silt, clay, and organic carbon contents were -0.67, 0.74, 0.12, and 0.70, respectively. Compared to the DSA > 0.25 mm, the effect of soil organic carbon on the WSA > 0.25 mm was arisen while the influence of clay fraction reduced.