Ammonium fixation as affected by soil temperature and its management

The fixation of the fertilizer-NH4+ affected by soil temperature and its management through nitrogen application under different seasonal temperature were studied in two main soils of Hebei, using incubation and 15N tracing methods. Results showed that the fixation rate of the fertilizer-NH4+ was 18%～22.92% at normal temperature (25℃) and 37.69%～45.31% at low temperature (-5～0℃) under incubation condition. The fertilizer-N fixation increased temporarily when it was applied in low temperature season under pot culture condition. But the fixed fertilizer-N was released almost entirely during the growing season of the wheat. Fertilization,under low temperature, the higher nitrogen efficiency was obtained. The residual rate of the fertilizer-N increased and its loss decreased.