Effects of temperature and soil type on nitrogen mineralization

Variation between soils in the response to temperature of nitrogen (N) mineralization was investigated in laboratory incubations. Three types of soils with different soil organic matter contents including black soil (Phaeozem), chao soil (Cambisol) and red soil (Acrisol) were sampled from farmlands of different regional climates of east China. The soils were incubated at 15, 20, 25 and 30oC and constant moisture conditions and the accumulation of soil extractable NO3-N and NH4-N was followed for 15 days. First-order rate equation was fitted to data to estimate net mineralization rate constants (k0) and the size of the mineralizable part of native soil N (N0). The accumulated N mineralization increased by the sequence of Red soilBlack soilChao soil for 1520oC and a sequence of Black soil Red soilChao soil for 2030oC. Soil net N mineralization was significantly affected by soil organic matter and total N, and rate constant (k0) by soil C/N ratio.