Estimating osmotic pressure in soil solutions of saline soils to evaluate the salinity effect on crop yields

Authors: Pachepsky, Yakov; YAKIREVICH, ALEXANDER - Ben Gurion University Of Negev; PONIZOVSKY, ALEXANDER - Collaborator; GUMMATOV, NIZAMI - Azerbaijan Research Institute Of Crop Husbandry

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2023
Publication Date: 10/30/2023
Citation: Pachepsky, Y.A., Yakirevich, A., Ponizovsky, A., Gummatov, N. 2023. Estimating osmotic pressure in soil solutions of saline soils to evaluate the salinity effect on crop yields. Geoderma. 23(4); article e20299. https://doi.org/10.1002/vzj2.20299.
DOI: https://doi.org/10.1002/vzj2.20299

Interpretive Summary: Soil salinity is the menace for agriculture. Salinity of soil pore water changes the energy of water in soils. Because of that, the more salts are in soil, the more difficult for plants to take in soil water and nutrients. Osmotic pressure is the measure of salinity-related soil water energy component. Osmotic pressure is very difficult to measure. Instead, soil electrical conductivity or chemical composition of soil pore solution are measured. Currently electrical conductivity is measured most often. However the solution composition has been and still is measured in some regions. This work aimed to relate both solution composition and electrical conductivity of soil to the osmotic pressure and in this way establish a bridge between two existing methods of soil salinity characterization. The computer model was developed and a large database on soil pore solution composition was used with this model. Predicted concentrations of highly soluble salts appeared to be well correlated both with osmotic pressure and with the electrical conductivity. This work will be of use for salinity control specialists who need to optimize irrigation water use in arid and semiarid regions.

Technical Abstract: The osmotic pressure in soil solutions becomes as salinity increases, and plants cannot take up enough soil water. Therefore, the osmotic pressure of soil solutions can be used as the important metric of plant growth conditions in regions affected by soil salinization. Measurements of osmotic pressure are labor- and time-consuming. The objective of this work was to determine a more readily available soil salinity metric that could be used to estimate the osmotic pressure in soil solutions. The model to compute the osmotic pressure from soil solution composition was developed and validated with data from U.S. states Washington, Oregon, Colorado, and Idaho. The mean relative error was 7%. Then this model was applied to 300 data sets on soil solutions from various salinity-affected regions of Eurasia. The correlation coefficient between logarithms of concentration of highly soluble (not including carbonates and sulfates of calcium and magnesium) in soil solutions at saturation and logarithms of osmotic pressure values was above 0.99. The concentration of highly soluble salts in soil solution at saturation was chosen as the predictor of the osmotic pressure and was used to develop nomograms for evaluating the salinity-related yield loss for major field crops, vegetables, and fruits.