Soil quality is the most suitable index to an assessment of the stability of terrestrial ecosystems, especially agro-ecosystems. To determine the effects of agricultural practices on soil organic matter, species richness and abundance of soil invertebrates, a study was conducted in three regions of Razavi and Northern Khorasan Provinces, Iran. Soil were taken from in each winter wheat field of the study area, and as well from some samples selected areas of the natural ecosystem. Soil texture, organic matter, diversity in and abundance of soil invertebrates were determined. The results showed that climate affects soil texture as well as organic matter, so that with increase in mean annual precipitation and a decrease in mean annual temperature, soil texture was finer and soil organic matter increased. Organic matter was affected by agricultural practices and followed increasing trend with in agricultural systems going on in each region. Also diversity and abundance of soil invertebrates increased with prevalence of agricultural systems. As a whole, we suggested that soil quality increased in agricultural systems.