Particle size fractionation as a method for characterizing the nutrient content of municipal green waste used for composting

Abstract In order to better characterize mechanically shredded municipal green waste used for composting, five samples from different origins were separated into seven particle size fractions (>20 mm, 10–20 mm, 5–10 mm, 2–5 mm, 1–2 mm, 0.5–1.0 mm and 2 evolution and mineral N accumulation with decreasing particle size. Results suggested that during composting of bulk green waste (with a high initial C/N ratio such as 50:1), mineral N accumulates because decomposition and net N immobilization in larger particles is slow while net N mineralization proceeds rapidly in the smaller ( 4 + -N, but over time, nitrification proceeded resulting in accumulation of NO 3 − -N. It was concluded that the nutrient content, N mineralization potential and decomposition rate of green waste differs greatly among particle size fractions and that chemical analysis of particle size fractions provides important additional information over that of a bulk sample.