JWSS - Journal of Water and Soil Science

One of the reasons for soil salinization is the accumulation of salts in it by transmission through water and wind. In order to investigate the phenomenon of transfer of salts with dust in the arid regions of the north of Yazd- Ardakan plain, field samples were taken using 32 MDCO sediments traps with uniform dispersion in an area of 20,000 hectares at some stage in 4 seasons of 2017. After washing the sediment collector with a liter of distilled water in the field and transferring the samples to the laboratory, for the quantitative analysis of saline dust, similar to measuring the Water Electrical Conductivity (EC_w), the Total Soluble Solids (TDS) were additionally measured through evaporation technique. The form and distribution of the dust particle size were additionally investigated using a Scanning Electron Microscope (SEM) tool. Within the qualitative examine of salts, effective cations and anions in salinity including Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺, C1^-, HCO^-₃ and SO^-₄ were measured The results confirmed that, in general, the fallout was 11.1 g.m^-2 of soluble material with dust particles (13.28%) in the course of only 12 months. Particles with a diameter of 5 to 10 microns were the most frequent. Considering the high correlation between C1^- and Na⁺ in the spring, autumn and winter, due to the high correlation between Ca⁺⁺ and SO^-₄ in summer dust, sodium chloride (NaCl) and gypsum (CaSO₄) 2H₂O)), the most abundant composition of dust- containing salts could be expected in these seasons. By determining the percentage of solutes in the fallout dust, it was observed that the impact of the amount of the deposited salt from dust was slight and insignificant in the short time period; with the assumption of no change in the rate of subsidence, it was anticipated that it would explain the poor salinity in non- saline mass soils for up to 10 cm in 72 years. In general, the capability of airborne salt in increasing the soil salinity in the study area can be in long- term periods. Therefore, it is recommended to investigate other environmental effects of this phenomenon in order to identify its hazards.

The purpose of this research was to investigate the trend of annual changes in Yazd station's meteorological parameters including minimum and maximum average daily temperature and average daily precipitation (1961-2005), as well as the predicted annual mean of these parameters in the three upcoming thirty years of the 2040s, 2070s and 2100s, by the SDSM model, under RCP2.6, RCP4.5, RCP8.5, A2, and B2 scenarios. Accordingly, by using the coefficient of determination and the MAE, R², RMSE indicators, we evaluated the data generated by the SDSM model in comparison with the observed data in the base period. The lowest value of R² based on the calibration and validation of the mean values of observed and simulated SRES was obtained for precipitation (86 and 80%). In terms of the R² evaluation index, the accuracy of the small-scaled results of the minimum and maximum average temperature values was more than that of the average precipitation; however, in terms of the MAE and RMSE evaluation indicators, the accuracy of the small-scaled results of the average precipitation was higher than that of the minimum and maximum average temperature values. Subsequently, HadCM3 large-scale climatological data was used to predict the future periods (2010-2100). The results indicated that the temperature was raised in all months and seasons and the precipitation was decreasing in most of them, thereby confirming that the climate was changing in the studied region.