Abstract
Differences in the nitrogen fertilizer efficiency of cattle manure compost and swine manure compost were examined with regard to the concentration of acid-detergent-soluble organic matter (ADSOM). An incubation experiment was performed at 30℃, and there was little change in the amount of inorganic nitrogen content (including magnesium ammonium phosphate) in the samples containing ADSOM at concentrations of <250mg g^<-1> compost. However, after immobilization for approximately 7 days, inorganic nitrogen was mineralized in the samples containing ADSOM at concentrations of ≥250mg g^<-1> compost. These results suggest that nitrogen fertilizer efficiency can be predicted on the basis of inorganic nitrogen content in compost containing ADSOM at concentrations of <250mg g^<-1>. This prediction method was verified by experiments of komatsuna cultivation (〜30 days) and sorghum cultivation (〜150 days).
