The amount of residue or even living cover on the soil surface greatly affects soil temperature.
Soil temperature, in turn, affects microbial activity and crop growth.
For spring cash crops, the cooling effect of living cover/mulch generally slows crop growth and is disadvantageous. For summer cash crops, the moderating effect of residue on soil temperature, along with the increased moisture retention, may be advantageous.
Tillage and soil temperature
Tillage generally increases soil temperature. Along with the increased (temporary) aeration from tillage, this can increase microbial activity and nutrient cycling.