جستجوی مقالات مرتبط با کلیدواژه "سدیمی" در نشریات گروه "آب و خاک"

Due to the insufficient suitable agricultural land and the large extent of saline-sodic soil across the world, the reclamation of the salt affected soils is necessary. Studies indicate that the addition of biochars to the soils improves their qualities, increases crop yield, and reduces salinity stresses. In the present study, the effects of adding various biochars on some chemical characteristics, including the concentration of soluble cations and anions of saline-sodic soil with clay-loam texture, which was taken from the Kafoun region in Mazandaran province, were investigated. Several kinds of simple and acidic biochars were produced from agricultural residues (rice straw) and wood factory waste (dicer) at 300 ° C and added to saline-sodic soil in three levels 0, (2.5, and 5%). The results showed that the rice straw biochar reduced the soil pH more than the biochar obtained from dicer. It was also understood that dicer biochar reduced the amount of soil EC, SAR, soluble sodium, potassium, calcium, and chloride. However, the rice straw biochar, acidic rice straw biochar, and acidic dicer biochar increased the amounts of those criteria and elements. Ultimately, it can be concluded that only the dicer biochar should be added to saline- sodic soil, in the absence of leaching and drainage.

Soil micromorphology is a branch of soil science which studies undisturbed soil samples using microscopic methods and the image analysis technique can promote speed, accuracy and ability of micromorphic studies. Soil pores due to their effect on the most of processes and properties of soils and also on interaction between soil, water and plant, have spacial importance. In this study, soil pores type and total porosity of saline-sodic soils were studied using micromorphic and Image Analysis techniques in a transect composed of eight soil profiles in the west of Urmia Lake. According to microscopic observations, pore types in these soils were vughs, channels and planar voids but Voids size and frequency in different horizons of each profile and all eight profiles were different. Average values of vughs, channels and planar voids in each thin section were about 45- 50%, 35-45% and 5-25%, respectively. Comparison between thin section description and Image Analysis showed that frequency and the range of size of pores in Image Analysis technique was greater than that of thin section description. The differences of measured total porosity between Image Analysis and thin section description in profiles 1 to 4 were 10.7, 7.83, 6.7 and 9 percent respectively. The reason of this difference is that, in thin section description technique, some of voids are too small, so they cannot be seen and are not measurable, whereas, in Image Analysis technique the measurement of size and frequency of voids were based on the number of pixels and this leads to greater values in Image analysis technique.

The salinity of water and soil is called white death in many countries, because of its importance. Generally, the quantity of leaching water, energy consumption and time usage of soil remediation procedure are important factors which affect suitable method of soil reclamation. Electrokinetic (EK) is a physical method for salt extraction such as chemical, Organic and inorganic compounds. In this study, the horizontal placement of electrodes along with leaching procedure was used in Electrokinetic remediation of a saline-alkaline soil. For this purpose, two aluminum and reticular electrodes was placed above and under the soil column as anode and cathode, respectively. The soil columns heights were 10, 20, 30 and 45 cm. Then leaching water (30 mm) every day and totally Equivalent to Four times pore water was entered to soil and properties of drain water was measured. Although, leaching procedure without applying electrokinetic technique was done as control treatment. The results showed that Electrical Conductivity (EC) of drain water and current rate was changed sinusoidal in EK. Although, PH and temperature of drain water was changed between 6.8 to 9 and 23 to 35 centigrade, respectively. Leaching of cations increased in EK technique significantly (p

In order to comparision of the micromorphic properties of saline-sodic and nonsaline-nonsodic soils in the west of Urmia Lake, four soil profiles (2profile in saline-sodic soils and 2profiles in nonsaline-nonsodic soils) were investigated. These profiles were described and sampled using standard methods. soil samples were used for physico chemical analysis and undisturbed and oriented samples were used for thin section preparation. Thin sections were studied using polarizing microscope in PPL and XPL lights. Thin sections studies showed that saline-sodic soils are structure less (apedal), and their voids are mostly vughs and channel and as a result, their, nonsaline-nonsodic soils are pedal with compound packing voids, vughs and planar voids and as a result, The b.fabric in these to group of soils is crystallitic. In saline sodic soils pedofeatures are illuvial clay coatings, salt accumulations including coatings and infillings of halite in channel and vughs. These pedofeatures were not seen in nonsaline-nonsodic soils. Organic coatings were seen as black colored films on peds and in some cases mixed with groundmass of saline-sodic soils.Calcium carbonate accumulations as nodules and coatings and nodules and coatings of iron and Mn oxides were seen in both saline-sodic and nonsaline-nonsodic soils.

Micromorphology is the branch of soil science that is concerned with the description, interpretation and, to an increasing extent, the measurement of components, features and fabrics in soils at microscopic level. The advantage of micromorphology is that, in micromorphological studies the soils are studied in their natural and undisturbed form and so, one can follow the processes that take place in a low rate. In this research, in order to study the micromorphic properties of saline-sodic soils in the west of Urmia Lake, four soil profiles were studied. The profiles were described and classified using standard methods. Disturbed soil samples were used for physic-chemical analysis and thin sections were prepared from undisturbed and oriented samples and were studied using polarizing microscope. According to the results, the most of studied soils were apedal and their voids were mainly vughs and channels. These soils were vughy, channel and massive microstructure and their b-fabric were mainly crystallitic. The micromorphic pedofeatures in these soils were illuvial clay coatings, accumulations salts as discontinues coatings of cubic and suhedral halite crystals on voids and aggregates, continues halite coatings and halite infillings in vughs and channels, calcium carbonate accumulations as typic nodules, infillings and coatings, redoximorphic accumulations as nodules in the groundmass and coatings on voids and skeletal grains, and finally, organic coatings as black films on peds and in some cases mixed with groundmass of the soil.

The reclamation of salt-affected soils which occur on 831×106 ha can be effective in increasing agricultural production. Cultivation of plant species which are resistant to salinity can improve the soil by increasing the solubility of calcite and releasing the calcium in soil solution. This study was conducted as a column experiment with a saline-sodic soil (SAR = 23. 8، EC= 12. 88 dS m-1، pH= 7. 7، CaCO3= 15. 15 %). Three plant treatments including Sesbania acuelata، Cyanodon dactylon and Rubia tinctorum، and three chemical treatments including gypsum in two levels (50% and 100% gypsum requirement) and sulfuric acid with a control were arranged. All treatments were replicated 3 times. The soil columns were similarly leached by 41 liters of tap water during 30 days in 8 stages. After leaching، SAR and EC in soil، the amounts of sodium in leachate and total amount of sodium in plants shoot were determined. Results showed that the SAR was decreased compared to control by the plant treatments and the chemical amendments by about 59% and 65%، respectively. Moreover، two plants of Cyanodon dactylon and Rubia tinctorum had maximum amount of leachate sodium، which shows an impressive role of these plants in dissolution and leaching of exchangeable or sediment sodium in comparison with the other treatments. According to salient performance of phytoremediation in improvement of physicochemical properties of soil compared to chemical amendments، phytoremediation can be recommended as a profitable low-cost and effective method for remediation of saline-sodic soils.

Salinity and sodicity are of major problems of arid and semi-arid regions soils and account for lowering soil quality. In order to improve the physical and chemical qualities of these soils، a composite sample of a saline-sodic clay soil (ECe= 11. 5 dS/m، SAR= 13. 23) from Bilverdi agricultural research center of Islamic Azad University of Tabriz branch was collected. The experiment carried out in a greenhouse، was factorial with complete randomized design with 3 replications. The experimental factores (treatments) were a)polyacrylamide (PAM) (0، 0. 25 and 0. 5 g/kg soil)، b) pumice (0، 50 and 100 ton/ha) and c) municipal waste compost (0، 30 and 60 ton/ha). After complete mixing of these amendments with pre-wieghed amount of soils in plastic pots، the pots were kept in the greenhouse under 18-25 ◦c. The soil moisture varied in the range of 0. 5 FC to FC. Ten wetting and drying cycles were imposed to the pots using tap water with EC=0. 387 dS/m and SAR= 1. 014. After incubating of the pots for 100 days under the described conditions pH، saturated electrical conductivity (ECe)، sodium adsorbtion rate (SAR) and organic carbon (OC) were determinded in the disturbed samples taken from the pots. Saturated hydraulic conductivity (Ks) and slope of soil moisture curve at the inflection point (Si) were also determinded in undisturbed samples taken from the surface layers of the pots. Analysis of variance and mean comparisons between the treatments showed that pumice and compost reduced pHsignificantlyby 0. 37 unit in comparision to the control. Pumice and PAM also reduced ECe from 34. 9 to 43. 97 percent relative to the control. while compost raised ECe by 186. 69 percent relative to the control. The result clearly showed a positive effect of pumice and compost on reducing SAR by 58. 97 percent and positive effect of PAM and compost on increasing OC by 26. 67 percent in comparision to the control significantly. Due to strong adhesive effect of PAM for the soil particles، and thus its aggregation effect، this amendment led to more larger pores and as a result significantly raised Ks up to 3 cm/hr (638. 3%) and Si to 0. 074 unit (160. 87%) as compared with the control. Generally، it seems that using PAM at the beginning of saline-sodic soils reclamation may considerably facilitate the practice because it greatly improves hydraulic conductivity. Taking the benefits of pumice or compost will be the next step