Abstract
Investigations were made on the growth of komatsuna and Italian ryegrass under fertilization with coffee residue after soybean cultivation under mulching with coffee residue. 1) Growth and yield of soybean were increased by mulching with 95 Mg ha^<-1> of coffee residue in order to enhance the mulching effect and improve Mg nutrition. 2) Top growth of komatsuna was severely inhibited by the incorporation of 47.5 Mg ha^<-1> and 95 Mg ha^<-1> of coffee residue after the harvesting of soybean. Top growth of Italian ryegrass was not affected by the incorporation of 47.5 Mg ha^<-1> of coffee residue after the harvesting of komatsuna. However, growth was remarkably decreased with the incorporation of 95 Mg ha^<-1> of coffee residue. 3) The contents of inorganic nitrogen, available phosphate and exchangeable cation were higher in soil supplemented with coffee residue had been applied as compared to non-application control soil, except for the content of inorganic nitrogen in the soil supplemented with coffee residue at the time of komatsuna sowing. The content of available nitrogen in the soil increased with the increased application of coffee residue at all sampling times. Therefore, the decrease in top growth of komatsuna and Italian ryegrass was not only due to immobilization of the soil nitrogen when the soil was supplemented with coffee residue. 4) The number and biomass of weeds decreased as the amount of coffee residue supplemented increased.
