Comparison of coarsely shredded and finely shredded apple prunings in composting with poultry manure and calcium cyanamide.

摘要

The effects of the shredding size of apple prunings on the compost maturation process were studied in Japan during the 344-day period of composting. Two composts were prepared from the coarsely shredded (compost A) and finely shredded (compost B) apple prunings by mixing with poultry manure and calcium cyanamide. Compost A was maintained at a higher temperature than compost B. Particle size fractionation of the compost samples revealed disintegration of woody materials and a decline in the C:N ratio of coarse particles during the composting period, the changes being faster in compost A than in compost B. When the compost samples taken at 203 and 344 days were incubated in a soil with ammonium sulfate, compost A did not show any immobilization of inorganic nitrogen whereas compost B showed slight immobilization even after the 344-day period of composting. Thus, it was concluded that the maturation process of the compost from the coarsely shredded prunings proceeded faster than when the finely shredded prunings were used. From a seedling growing test using Komatsuna (Brassica campestris), no inhibitory effects on plant growth were observed for either compost after the 203-day period of composting, and the presence of sufficient amounts of inorganic nitrogen was confirmed in the soils after the harvest of Komatsuna seedlings. This fact demonstrated that irrespective of the shredding size of apple prunings, the 203-d period of composting provided products which had no inhibitory effects on plant growth.