『Summary
　The productivity of tropical lowland moist forests is often considered to be limited by the availability of phosphorus. Organic phosphorus is often abundant in tropical soils, but its role in forest nutrition is largely unknown. We addressed this by using a large-scale litter manipulation experiment to investigate the stability of soil organic phosphorus in a tropical lowland forest in Central Panama. Three years of litter removal reduced the organic phosphorus concentration in the surface 2 cm of mineral soil by 23％, as determined by NaOH-EDTA extraction and ³¹P-NMR spectroscopy; this included decreases in phosphate monoesters (20％) and DNA (30％). Three years of litter addition (equivalent to adding 6 kg P ha^-1 per year) increased soil organic phosphorus by 16％, which included a 31％ increase in DNA. We did not detect higher-order inositol phosphates, despite their abundance in mineral soils of temperate ecosystems. Our observed turnover rate suggests that even the 0 - 2-cm layer of the mineral soil contributes a fifth of the total phosphorus needed to sustain above-ground growth in this forest. Soil organic phosphorus is thus likely to make a more important contribution to the nutrition of semi-evergreen forest plants than has hitherto been acknowledged.』

Introduction
Materials and methods
　Study area
　Gigante Litter Manipulation Project
　Soil sampling and preparation
　Solution ³¹P NMR spectroscopy
　Other chemical analyses
　Statistical analysis
Results
　Phosphorus fractions
　Phosphorus composition determined by solution ³¹P NMR spectroscopy
　Total soil carbon and nitrogen
　Discussion
Acknowledgements
References