جستجوی مقالات مرتبط با کلیدواژه « بافت خاک » در نشریات گروه « اکولوژی »

In this research, the effects of Haloxylon aphyllum on physical and chemical charactristics of soil considering the age of the plant was studied. The effects of 2, 5 and 10 years old Haloxylon aphyllum at two depths of 0-30 and 30-60 on physical and chemical properties of soil including total nitrogen, total phosphorus, total potassium, soil organic carbon, soil texture, pH, electrical conductivity and carbon-to-nitrogen ratio of soil were evaluated. In this research, 30 soil samples from underneath of Haloxylon aphyllum (10 samples for each age and 5 samples for each depth) and 30 samples between the plants were taken and their physicochemical and chemical properties were measured in the laboratory. Then, the data were analyzed using ANOVA and Mann-Whitney tests in SPSS software. The results showed that planting of Haloxylon aphyllum and its age at two studty depths have a significant effect on pH, but has no significant effect on EC. There was no significant difference between the soil texture in the experimental area and the control area, but the amount of sand and silt just for biennial shrubs in both soil depths had significant change. The implantation of Haloxylon aphyllum on N and OC at 0-30 depth has a significant effect, but does not affect the depth of 30-60 cm, but the age of the Haloxylon aphyllum in both depths has a significant effect on N and OC content. Vegetative planting in both depths of 0-30 and 30-60 was not significantly affected by P, K and C/N variables, and the age of the plant in both depths was significant on K soil and at 0-30 with P soil. In general, the results of this study showed that the effect of age on the change in chemical properties of soil is significant and with increasing age of the site (the age of Haloxylon aphyllum grafts) this effect is more evident.

Investigating the relationship between diversity, total number of mites and number of adult and immature mites with the type of culture were the main objective of this experiment.

In order to determine the frequency and diversity of Oribatida mites, regular and random sampling of different soil horizons belonging to 21 habitats of Marand region of East Azerbaijan province was performed in the summer of 2014. Sampling was performed by digging soil profiles and sampling from different horizons. After extracting the mites from the soil samples, microscopic slides of them were prepared and identified. Then, the texture type of the studied soils was determined. Finally, after calculating the Shannon-Wiener diversity index, the relationship between diversity, total number of mites and number of adult and immature mites with the type of culture was investigated using MSTAT-C software.

59 species belonging to 44 genera and 28 families were collected and identified, most of which were adults. Among them Epilohmania cylindrica cylindrica and Discoppia (Cylindrappia) cylindrica species have the highest relative abundance. The dominant mite D. (Cylindroppia) cylindrica had the highest percentage in wheat fields. 9 species were collected only from pastures, 11 species only from wheat fields, 4 species only from sunflower fields and 4 species only from gardens. The highest diversity indices were obtained in mixed garden 3, sunflower fields and pastures and the lowest diversity indices were obtained in wheat fields. The diversity and number of adult and immature mites did not show significant differences in different cultures and horizons. The total number of mites did not show a significant difference in different cultures, but different horizons showed a significant difference in the total number of mites at a probability level of 5%. The second horizon had the highest number of mites and the third horizon showed a smaller number. The highest variability was observed in the second horizon and the lowest variability was observed in the third horizon. Among the cultures, sunflower had the highest number of mites. The interaction effect of cultivation and horizon was not significant in any of traits. The highest total number of mites was observed in the second horizon with clay loam texture in which the number of adult mites was more than immature mites. The greatest variability was observed in the first horizon with sandy clay loam texture.

Based on the index of species diversity and frequency of mites obtained, it can be concluded that the types of crops and localities studied are on the same level in terms of contamination or non-contamination with chemicals and heavy metals. The difference in the frequency and variety of oribatid mites in different horizons is due to the sensitivity of these mites to moisture. Moisture in the upper soil horizon at the time of sampling has led to the migration of these mites to the second horizon with higher moisture content.

At the present, erosion is one of the most important of environmental problems in the Iran watersheds. Therefore, determine the sediment and soil erodibility is very important for conservation and management of natural resources. The aim of this study is evaluate the spatial distribution of soil erodibility and relationship with some of the soil properties using geostatistical methods in the Khoor and Biabanak region. For this purpose, 33 soil samples were taken from depths of 0-50 cm along three transects from playa until mountain units to determining the components of sand, clay, silt, organic carbon and organic matter. Values of K factor and SEI were calculated by values of these parameters. Finally, to determine the spatial distribution, interpolation methods were tested and the most suitable method was chosen. The results showed that Radial Basis Function was the most suitable of interpolation method for the spatial distribution of the elements of sand, clay and K factor with RMSE 3.27, 3.22 and 0.0036, respectively. The simple Kriging method was suitable for carbon components and organic material with RMSE 0.34 and 0.59, respectively. For silt, Kriging Ordinary with RMSE 0.88, and for SEI index, Universal Kriging method with RMSE 0.0014 were suitable. According to the results of soil erodibility values, minimum and maximum amount of K factor with 0.025 and 0.07 t h MJ− 1 mm− 1, as well as minimum and maximum values of SEI with 0.03 and 0.07 are extensive in the East, and West and North West area, respectively.