The purpose of this paper is to determine the relative effects of soil organic matter, salinity and CaCO3 on plant density in semi-arid regions. In this paper, the degree to which species density varies with these soil properties was investigated. The study was conducted in the central province of Cankiri, which is located in the middle Kizilirmak section of the Central Anatolia region. The plants collected from the study area with salt-free, calcareous and low-level organic matter are characterized by their flowering in early spring and their herbaceous nature. For this purpose, specific research models were developed to examine the importance of soil organic matter, salinity and CaCO3 on species density. The relationships in the research model among these abiotic factors and species density have been derived from previous studies. The research model was evaluated using structural equation modelling (SEM) based on data from 116 research area plots. The SEM results showed that even though direct and indirect effects of soil organic matter on plant density are significant, when calculating total effects of soil organic matter on plant density, soil organic matter has no significant overall effect.