Abstract
The growth of several crops and soil physico-chemical properties in the soils after a two-year successive application of coffee residue was investigated to find an indicator of the disappearance of inhibitory effects originating from coffee residue. 1) The growth of several crops increased during the period when the decomposition rate of coffee residue was above 0.5 kg kg^<-1>. 2) The concentration of available P_2O_5, exchangeable Ca and Mg tended to be larger in the soil after coffee residue was applied than in soil without coffee residue. However, the concentration of inorganic N and exchangeable K were smaller in the soil with coffee residue application during the period when the growth of several crops were suppressed. 3) There was an inhibitory effect of treatment with coffee residue on komatsuna (Brassica campestris growth, even when the application rate of N and K fertilizers was increased. 4) There was no relationship between crop growth and the concentration of water-soluble phenol or soil C/N ratio. 5) The physical properties of the soil were improved by coffee residue application, while there were no growth inhibitory effects of coffee residue on several crops. Based on the above results, we concluded that the inorganic N content was an indicator of the disappearance of inhibitory effects originating from coffee residue, although it was not a direct factor.
