s:1097:"TI Decomposition and nitrogen mineralization of leaves of Paraserianthes falcataria in an ultisol under field conditions AU Chintu R AU Matakala P M AU Zaharah A R AB The dynamics of N released from fresh leaves of Paraserianthes falcataria when applied as surface mulch to an Ultisol, and their effects on soil acidity, were studied under tropical field conditions in Malaysia. 15N-labelled residues were applied to confined microplots to trace the pathways and fate of mineralized N, and resin bags placed at 20 cm soil depth under the microplots collected leached inorganic N for quantification. A control treatment consisted of no residue application. The microplots were kept free of vegetation. Decomposition of the high quality residue was very fast with the likelihood that crop N demand would not be in synchrony with the rate of N mineralization. Nitrate was readily leached to 20 cm depth suggesting a high potential for N loss and poor N use efficiency in the system. The leaf mulch had a short term positive effect in the 0-10 cm soil depth as an ameliorant of soil acidity ";