JWSS - Journal of Water and Soil Science

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Investigation of paleosols plays a great role in paleoecological and paleoclimatological studies. They are also important in soil survey and planning, as they exhibit characteristics different from younger soils. Paleosols are those soils which formed under conditions different from present ones, and are either buried within sedimentary sequences or those which lie on persisting surfaces. Although such soils are widespread in central Iran and Zagros Zone, they have not been studied adequately. Paleosols are identified by different parameters such as morphological, physical, chemical, mineralogical, and micromorphological characteristics. In this study, morphological, physical, and chemical properties of three paleosols from Isfahan and Chaharmahal & Bakhtiary provinces were investigated. The profiles were on different landforms including alluvial fan, dissected old plain, and old lagoonal deposits. Soil profile in Segzi site, on old lagoonal deposits, had a very dark and thick layer at a depth of 45-60 cm containing some macrofossil shells. This shows that this area was covered by brackish water during the early Holocene. In Sepahanshahr profile, presence of strong clay coating and high concentrations of CaCO₃ indicates a wetter environment in the past than the present conditions with a precipitation of only 100 mm. In Emam-Gheis profile, a buried paleosol was identified with strong clay coating and free CaCO₃ horizons that shows more humid conditions. Evidences obtained from the three paleosols studied indicate that effective moisture in central Iran and Zagros regions during Late Pleistocene had been higher than its present levels.

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In order to investigate the effect of vermicompost on physical and chemical properties of soil, an experiment was carried out in split plot based on complete randomized block design in three replications in Sari Agricultural Sciences and Natural Resources University. The physical and chemical properties of soil included bulk density, particle density, total porosity, water holding capacity, field capacity, permanent wilting point, available water capacity, pH, organic carbon and electrical conductivity in soil. Six levels of fertilizer treatments (T1= control, T2= chemical fertilizer, T3= 20 tons vermicompost + 1/2 T2, T4 = 20 tons / hac vermicompost + 1/2 T2 , T5= 40 tons vermicompost + 1/2 T2 and T6= 40 tons / hac vermicompost) and three levels of application years, one year of fertilization (1385), two consecutive years of fertilization (1385 and 1386) and three consecutive years of fertilization (1385, 1386, 1387). The results of the study showed that the application of these treatments in soil were significantly effective in increasing the total porosity, water holding capacity, field capacity, permanent wilting point, available water capacity, organic carbon electrical conductivity and in decreasing the bulk density, particle density and pH compared to control. In Contrast years of consumption of fertilizer did not have any significant effect on the physical properties of the soil except for FC, PWP, AWC, pH, OC and EC. The interaction between years of consumption of fertilizers were significantly different only in particle density and field capacity.

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Usually, dry soil readily absorbs water .However, not all soils display such characteristics. Some soils (hydrophobic soils) show resistance to wetting. Because of the importance of this subject and lack of research, we evaluated the effect of heating on water repellency and some of soil physical and chemical characteristics. So soil was combined with compost and heated at deferent temperatures, 100, 200, 300, 400 and 500 °C for 30 minutes in an oven or muffle furnace. The results showed that control treatment and heated soil at 300 °C had WDPT and MED 45 (s), 17% and 80 (s), 23% respectively. So, little water repellency was present prior to heating the soil. When soil was heated up to 300°C, intense water repellency resulted, but it was abruptly eliminated by increasing the heating. The soil texture was changed from loam to sandy loam at high temperatures (400 & 500 °C) and the sand percentage was increased. Organic matter decreased by increasing the temperature. Amount of pH decreased up to 200 °C and then increased at 500°C because of increasing ash in soils. Diminution of mineral and organic matter caused EC to decline in all the heated soils.

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Dust deposition phenomenon is an important climatic and environmental issue in arid and semi-arid regions. The objective of this study was to examine important characteristics of atmospheric dust in Kerman as one of the major cities in arid areas of our country with high potential of dust production. Dust samples were collected monthly using glass traps installed on the roof of 35 one-story buildings in Kerman for 7 months from April 20 to Nov. 20, 2012. To compare the results of atmospheric dust with those of soil, 60 surface soil samples (0-10 cm) from outside Kerman and 35 soil samples from urban areas were also collected. Some physical and chemical characteristics such as pH, electrical conductivity, organic matter, calcium carbonate equivalent, and  particle size distribution were determined in dust and soil samples. The results of chemical analyses indicated that the amount of these properties is much higher than that in soils. Atmosphere dust particles appear to mainly originate from alkaline and saline soils surrounding the city of Kerman. Dust particle size distribution analysis further confirmed that dust particles have been transferred to Kerman city from medium to long distance areas.  Temporal variability in dust chemical properties indicates that the contribution of anthropogenic and natural sources to urban dust in Kerman has seasonal changes. Based on the results obtained, it is necessary to control dust production outside and inside the city and its distribution in populated areas employing proper management practices.