Carbon and nitrogen mineralization of white clover plants ( Trifolium repens ) of different age during aerobic incubation with soil

A 4‐month aerobic incubation experiment was conducted measuring carbon and nitrogen mineralization from white clover in soil at 25°C and optimal moisture conditions. Cumulative carbon mineralization from clover followed a double exponential function and was similar for tops and roots amounting to 77.5% of non‐lignin carbon initially present. Rate constants for the rapidly and slowly mineralized carbon fractions amounted to 0.21 d −1 and 0.02 d −1 respectively and were identical for tops and roots. Cumulative mineralization of nitrogen followed single first‐order kinetics and was lower for older tops (31%) than younger ones (42%) and roots mineralized least relative amounts (28%). Rate constants of nitrogen mineralization from tops of different ages were fairly similar (0.058 d −1 ) whereas those for roots were lower (0.035 d −1 ). A simple predictive measure for potential N mineralization of plant material was proposed assuming a C/N ratio of 8 in the stabilized material and a constant fraction of the non‐lignin carbon to be mineralized.