Chemical Behavior of NaCl added to Andosol, Jahgaru Soil, and Masa Soil in Relation to Saline Damage to Tomato

Abstract

The effects of salt （NaCl） on soil electrical conductivity and ion elution were investigated in three Japanese soils （Masa soil, Andosol, and Jahgaru）, as well as the effects on tomato growth and absorption of inorganic components. The electrical conductivity （EC（1 : 5）） of the soil suspension and the saturated soil extraction （ECe） increased with salt addition with a high correlation efficiency. The conversion factor from the EC （1 : 5） value to the ECe value was 7.66 for Andosol and 7.08 for Jahgaru; however, Masa soil had a higher value of 18.1 and the soil was susceptible to salt damage. SEM-EDX analysis revealed an increase in Na and Cl concentrations and a decrease in Mg concentration in the surface of the Masa soil containing added salt.

Tomato growth was affected by adding salt（ EC（1 : 5）= 0 .75 d S / m）, and only the plants in the Masa soil died. Tomato growth responded according to ECe rather than EC（1 : 5）. In the Masa soil and Jahgaru, adding salt enhanced the release of Ca and Mg from the soil into the soil-saturated extract water. The concentration and composition of cations in the saturated soil extract strongly affected the inorganic salt composition in the tomato roots. In Jahgaru, the Ca concentration in the roots was high in response to the high Ca / Na ratio in the saturated soil extract. Compared with Masa soil, the Na concentration of the plant top in Jahgaru was suppressed, which may be caused by mitigation of Ca from Jahgaru.