新疆盐渍土渗透势与盐分的关系

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

采集新疆不同类型不同质地的盐渍土共30个采样点450份盐碱土土样,分别用土水比为1∶1和1∶5进行浸提,测得浸提土样渗透势、总盐、pH、主要离子含量等化学参数,研究土水比为1∶1和1∶5浸提液渗透势的相互转换关系以及渗透势和总盐的关系。结果表明:新疆盐渍土土水比为1∶1和1∶5之间的渗透势具有极显著线性相关性,两者相互转换方程式为:Ψs1∶1=4.32Ψs1∶5+0.007(R2=0.97,P<0.000 1);土水比为1∶1的土壤溶液渗透势与总盐的方程式为Ψs1∶1=67.26-19.67ln(St1∶1+30.46)(R2=0.96,P<0.000 1);土水比为1∶5的土壤溶液渗透势与总盐的方程式为Ψs1∶5=232.59-39.82ln(St1∶5+343.68)(R2=0.90,P<0.000 1)。这些方程能够很好地诊断新疆盐渍土的盐渍化程度,将对于我国盐渍土的改良应用以及盐生植物的种植具有重要意义。

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 ＆lt; 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 ＆lt; 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 ＆lt; 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