Relationship between Osmotic Potential and Total Salt Content in Saline or Alkaline Soil in Xinjiang

The relationship between osmotic potential and total soil salt content was used to indirectly describe soil salinization degree. Soil osmotic potential measured by extraction was closely related to the soil-water ratio. Therefore,it is very important for setting up the conversion relationships between osmotic potentials in 1∶ 1 and 1∶ 5 soilwater extracts. Four hundred and fifty saline or alkaline soil samples with different types and textures were collected in whole Xinjiang,and their osmotic potential( Ψs),total soil salt content( St),pH value,and main cation and anion concentrations in 1∶ 1 and 1∶ 5 soil-water extracts were determined. The results showed that osmotic potential in 1∶ 1 soil-water extract was significantly associated with that in 1∶ 5 one,and the conversion relationship could be expressed by equation Ψs1∶1= 4. 32Ψs1∶5+ 0. 007( R2= 0. 97,P 0. 000 1). The relationship between osmotic potential and total soil salt content( St) could be expressed by equation Ψs1∶1= 67. 26- 19. 67ln( St1∶1+ 30. 46)( R2= 0. 96,P 0. 000 1) in 1∶ 1 soil-water extract and by equation Ψs1∶5= 232. 59- 39. 82ln( St1∶5+ 343. 68)( R2= 0. 90,P 0. 000 1) in 1∶ 5 soil-water extract respectively. For improving saline or alkaline soil and growing halophytes,these equations can be used to quantitatively assess the degree of soil salinization in Xinjiang,and the study results can provide a scientific basis for further researching saline soil or alkaline soil in Xinjiang