Effects of urea treatment on litter decomposition in Pasania edulis forest soil

Abstract

Five kinds of ammonia fungi were observed in a Pasania edulis forest after treatment with 1600 g · m⁻² of urea. The number of fungal fruiting bodies decreased with time, and disappeared completely within 6 weeks. The population of cellulose decomposing bacteria also decreased after urea treatment. Urea treatment brought about marked changes in soil pH, redox potential (Eh), and nitrogen content, but no significant changes were observed in carbon content. In this experiment, urea treatment promoted decomposition of branches, but inhibited decomposition of leaves. In urea-treated plots, the decomposition rate of leaves was lower than that of branches, and the decomposition rate of large branches was greater than that of small branches. However, in the control plots, the decomposition rate of leaves was greater than that of branches, and the decomposition rate of large branches was lower than that of small branches. This experiment indicated that litter (branch and leaf) decomposition was dependent on the texture and size of the litter components, and that ammonia fungi and cellulose decomposing bacteria were not closely related to the litter decomposition.