Effect of Salt and Thermal Stress on the Chemical and Mineral Properties of Soil
Khalid Ekhlayef N. Alhadidi *
Department of Soil Sciences and Water Recourses, College of Agriculture and Forestry, University of Mosul, Iraq.
*Author to whom correspondence should be addressed.
Abstract
Three sites were selected within Nineveh Governorate (Al-Salamiyah, Bartala, Al-Mawali) Because they are areas of agricultural importance. Samples were collected on 9/13/2024. Soil samples were taken from a depth of (0-30) cm. To prepare for analysis, well water samples were taken from the same study areas from which the soil was taken. The results showed the effect of wetting for five cycles with well water of different salt concentrations and drying at temperatures (5, 25 and 50) °C degrees Celsius on the chemical properties of the study soils.. The electrical conductivity values of the study soils increased with the increase in drying temperature regardless of the concentration of well water. In the Al-Salamiyah site, the electrical conductivity increased from (1.80 dSm-1) to (2.4, 5.5 and 6.4) dSm-1, in the Bartella site, the electrical conductivity values increased from (0.55 dSm-1) to (3.5, 5.8 and 6.8) dSm-1, while in the Al-Mawali site, the electrical conductivity values increased from (0.55 dSm-1) to (3.5, 5.8 and 6.8) dSm-1 when drying at (5, 25, 50) °C, respectively. The reason for the high electrical conductivity values is the high values of the main cations and anions that play a major role in the formation of salts in the soil (calcium, magnesium, sodium, potassium, bicarbonates, chlorides and sulfates) with the high drying temperature and concentration of the well water used for humidification.
The results showed that all minerals and salts were in a state of dissolution before the wetting and drying process, but some types of minerals precipitated after wetting and drying at different temperatures. Drying at a temperature of 5°C resulted in the precipitation of the following minerals (Calcite, Aragonite, Dolomite (ordered)), while when drying at a temperature of 25°C, in addition to the minerals that precipitated when drying at a temperature of 5°C, the precipitation of the mineral (Dolomite (disordered)) occurred. When drying at a temperature of 50°C, the precipitation of the minerals (Calcite, Aragonite, Dolomite (disordered), Dolomite (ordered)) occurred, with an increase in the saturation index values of the minerals that precipitated with an increase in the drying temperature and an increase in the solubility of the minerals that did not precipitate with an increase in the drying temperature, The results showed that when using irrigation water with a high salt concentration, the increase in temperature leads to a rapid increase in the concentration of salts in the soil.
Keywords: Soil salinity, precipitation, wetting and drying, temperature, global warming