Investigating the Impact of Haloxylon Plantations on Soil Chemical Characteristics (Case Study: Critical Center of Wind Erosion in Meybod)

Among the various methods of controlling desertification, the method of using plants that are compatible with this environment is considered the most suitable method. Plants are considered as one of the elements of this measure, but in the revitalization plans of arid and semi-arid areas, it is necessary to check the mutual influence of the cultivated species on the soil of the cultivated areas. The effect that plants have on the soil below them causes physical and chemical changes in the soil. By knowing the ecological needs of these species and comparing them with the existing conditions of new environments; In order to increase the productivity and meet the goals of restoration projects on the one hand and to know the effects of these species on the cultivation environment on the other hand, it is possible to firstly prevent the occurrence of financial losses due to the failure of cultivation due to the incompatibility of the species and secondly to prevent the creation of new stressful conditions in the areas under The effect of the species and finally, by using the obtained results, it is possible to recommend the plant species in the conditions of the environment similar to the study area.

The studied area is a part of Yazd-Ardakan Plain, the total area of ​​the project is 117,600 hectares (267 hectares of the field were selected for sampling). The average annual rainfall is about 64 millimeters, the average temperature is 21 degrees Celsius. The prevailing wind direction is mostly northwest and blows with an average speed of 4.5 meters per second. An area without any type of plant species with the same soil and geomorphological conditions was considered as a control. Sampling was done by random-systematic method under the canopy and in the control area at the soil surface depth (0-30 cm). Out of the 30 samples, 25 of which were collected in the field of tag work and 5 samples were collected as controls. It was harvested weighing about 2 kg. Factors (texture, organic matter, electrical conductivity, acidity, magnesium, calcium, sodium, and potassium) were measured in the laboratory. The results of the experiments were entered into SPSS software, and the normality of the data was first tested. After determining the results of normality, the independent parametric t test was used to analyze the normal data, and the non-parametric Mann-Whitney test was used for the non-normal data.

After entering the SPSS software, the data obtained from the samples were tested for normality with the Kolmogorov Smirnov test and the Shapiro-Wilk test. The purpose of performing the data normality test is that it helps us in using parametric or non-parametric tests for the next steps, the parameters of sand percentage, clay percentage, sodium, calcium and SAR are not normal. So, non-parametric test was used to analyze these parameters. The rest of the investigated parameters followed the normal distribution and parametric test was used for analysis.

The results of the data normality test showed that the parameters of sand percentage, clay percentage, sodium, calcium and SAR parameters do not follow the normal distribution and the parameters of electrical conductivity (EC), acidity (PH), carbon, potassium, silt, magnesium and ESP parameters are normal. using the results of the statistical test, points were given in the following way: in the investigated parameters that had a significant difference between the field and the control, if that parameter caused soil modification, a positive score was given, and if it had a negative effect on the soil A negative score was given. The calculated evaluation score for the cultivated area was +3, which shows that the soil had a better condition than the control area in terms of potassium, organic carbon, and magnesium. and have no witnesses. The parameters of potassium, organic carbon and magnesium have a significant difference at the probability level of 5%, which is distinguished by an arrow in the figure. The results of frequency analysis and independent t-tests and Mann-Whitney for the investigated parameters are explained as follows. Regarding the electrical conductivity, the results indicated that there is no significant difference in the field of tag work with the control. In terms of acidity (PH), the results showed that there is no significant difference between the treated area and the control area, and the soils of both environments are alkaline. However, it is not consistent in most of the researches such as Al-Gadi (2008), Rahimizadeh et al. (2009) who stated the increase in pH under the cultivation area as the result of their research. The results show a significant increase in the potassium element in the soil of the cultivated field compared to the control field. So that the amount of this element has increased from 366 to about 1299 mg, that is, it has increased about 4 times. This difference is statistically significant with a probability of 99%. In general, as mentioned above, the soil was not significantly different from the control field in terms of physical properties. In terms of chemical properties of the soil, only three parameters of organic carbon, potassium and magnesium have increased significantly in the soil, which shows that the soil has been strengthened in terms of these elements. Of course, the presence of these elements in the soil under the plant is due to their absorption from the depth of the soil by the plant roots and storage in the plant leaves. which accumulates at the foot of the plant after falling. Of course, it should not be overlooked that the salinity of the soil at the foot of the plants has increased compared to the control. And in terms of salinity, the soil condition has not improved.