Abstract: A field experiment was conducted to compare soil microbial populations, microbial-N status and soil physical and chemical characteristics in a no-till, unfertilized, direct-sown, wheat-rice, relay-cropping system (NTWR) and also in a conventional transplanted rice single cropping system (CTR). The wheat-rice system was imposed for 2, 4 and 7 years to identify the time course responses in the soil and crop. Recycling of crop residues in the wheat-rice cropping system generally increased the soil organic matter (OM) contents but reduced the level of available P2O5 compared with the conventional system. Generally the soil was fertile with a high initial organic matter contents. Organic matter was increased by 30% during the 7 years of wheat-rice cropping. Other soil physical features, bulk density and permeability to air and water indicated that soil structure could be improved in response to wheat-rice cropping. Seasonal variability of soil microorganisms suggested that 7-year cropping could improve soil physicochemical characteristics but mineral contents in relation to cation exchange capacity (CEC) would decrease after 4-years cropping. Soil tillage may adversely affect soil microbial dynamics. In conclusion, a no-till, unfertilized, direct-sown, wheat-rice cropping system, is likely to sustain grain yield by improving soil bio-physicochemical factors and is one of the most ecologically stable, economically sound and socially supportive wheat-rice production systems.