كليدواژه :
تبريز , املاح , dispersion , Infiltrability , Type of salts , Sodic soils , cation exchange capacity , شوري خاكها , كشاورزي
چكيده لاتين :
In order to study the salt affected soils of the two regions around Tabriz and to quantify salinity degree and type, and also to present appropriate methods for their reclamation, soil samples from Khajeh and Sattelli (northeast and southwest of Tabriz, respectively) areas were collected. The samples taken from different horizons, were analysed for physical, chemical and some fertility aspects. Physical characters included soil texture, soil moisture contents at different pF, infiltration rate, bulk and particle densities, and the porosity percentage. Chemical tests consisted the measurements of anions, cations, pH, EC, cation exchange capacity, neutral materials, gypsum, and also computation of some ionic relations. N P K and organic carbon content were also analyzed Soils from Khajeh region were saline (EC>=8 ds/m) and the neutral salts such as NaCl and Na2SO4 dominated the other solutes with Ca and Mg being in minor quantities. pH of the soil varied in the range of 7.5-7.8 and EC between 8- 24 ds/m. In the surface horizon, variation was more pronounced. The depth of groundwater in Khajeh region is low, so that soil salinity has been less influenced by its fluctuation. Reclamation of the soil is possible by excluding the excess salts through leaching. In addition to salinity in Sattelli area, sodicity also exists, which contributes to unfavorable physical conditions such as dispersion, low infiltration rate and aeration problems. In this region, EC of the soil ranged from 37 to 52 dSlm and pH from 9 to 9.5 .In contrast to Khajeh region, in Satelli soil salinity considerabley increases with depth and ESP was more than 15, reaching up to 57.4 in some samples. Carbonate and sodium bicarbonate have been built up and constitue the dominant type of the soil salts which has led to considerable increase in pH (9-9.5). Reclamation of these soils may be feasible not only by excluding the salts throuh leaching but also employing suitable amendment, in order to substitute Na by Ca for improving soil physical conditions. Addition of sulfur or its derivatives to lower pH, is also recommended.
