The invention relates to Stress Tolerant (ST) soil inoculant strains which are isolated from stress soil under stress conditions, by the method comprising the steps of: selecting stress tolerant soil bacteria from stress soils under stress conditions, examining the propagation of the isolates under stress conditions, and identifying the soil inoculant strain as stress tolerant if it meets the specified propagation criteria. The invention further relates to strain mixtures and soil inoculant compositions, as well as the uses thereof.