The mechanics evaluation of bonding strength between coating and substrate was performed with finite element method (FEM), and an improved test model was proposed. The maximum shear stress and the maximum tensile stress on the coating and substrate interface were analyzed. The influences of the step depth of model，dimensions of coating and the material properties of coating and substrate on the interface bonding strength of coatingsubstrate were compared and an optimum model was selected. The maximum tensile stress was obviously decreased in this model, and then the change of shear stress in different systems can be distinctly shown. Subsequently, the interface bonding strength in different systems was investigated.

The measurement of the electrical conductivity(EC) of the substrate in the greenhouse was performed by a portable realtime EC detector based on the electrical currentvoltage foureelectrode method and its results were discussed. At the condition of constant salt content(total ion content), if the water mass fraction in the substrate is lower than 50%,its EC is determined by both the salinity and the moisture of the substrate.When the water mass fraction is higher than 50%,its EC is determined only by the total ion content without connection with the moisture.When the water mass fraction is set at 65%,the EC detector indicates a power function relation between the detector output and the substrate EC,and the correlation factor of the proposed model reaches 0.970.When the water mass fraction of the substrate is about 45%,its EC can be predicted accurately by both the power function as well as the linear function models.