On Charactering Saturated Hydraulic Conductivity Of Saline And Sodic Soils

In this study we analyzed and compared saturated hydraulic conductivityKls, obtained by traditional laboratory experiments using field saline water andlaboratory tap water along the vertical direction within three sodic soil profilesof haloculture field. Falling and constant head methods were applied on threeundisturbed samples per pedogenic horizon using both saline and tap water. In thisstudy saline soil profiles covered a wide range of texture classes, can be globallyconsidered as the comprehensive representation indicator of hydraulic propertiescharacterization. The large spatial variability of hydraulic properties (horizontaland vertical), was found. Results revealed significant lower Kls values obtainedfrom fresh water compared to the data from saline water due to clay dispersion,calcium carbonate and gypsum dissolution, change in solution composition andconsequently change in structure. Significantly, the falling head method yieldedlower Kls values compared to the constant head method using both saline andfresh/tap water. Results indicated significant correlation between Kls valuesamong different methods. The significant correlation between those data andtexture, calcium carbonate and gypsum were observed. Whereas Kls of fresh waterwere more correlated to chemical composition. Overall, care should be takenin characterizing Kls of salt affected soils compared to conventional methods ofnormal soils in the laboratory. This is more pronounced when the data is used inhydrological model for sustainable agricultural management purposes. Therefore,the current study may be used as optimized and standardized method to determineKls of saline and sodic soils.

کلیدواژه ها:

Saturated hydraulic conductivity ، Saline and sodic soil ، Laboratory experiment