High N relative to C mineralization of clover leaves at low temperatures in two contrasting soils

•Initial net N mineralization of clover leaves was lower in clayey than sandy soil.•Initial N immobilization was higher at 8 and 15 °C than at 0 or 4 °C.•Initial ratio of net mineralized N to C increased with lower temperature.•Reduced microbial yield at low temperature plausible but needs direct assessment.