RELATIONSHIP BETWEEN SOIL NEUTRAL SUGAR COMPOSITION AND THE AMOUNT OFLABILE SOIL ORGANIC-MATTER IN ANDISOL TREATED WITH BARK COMPOST OR LEAF-LITTER

The effect of short-term bark compost (Ba) and leaf litter (Li) applic ations on the labile soil organic matter (SOM) status was investigated . The SOM status studied in this paper includes soil microbial biomass , soil available N, hot water extractable C (HwC) and N (HwN) and soil neutral sugar-C composition. The soil microbial biomass C (MBC) and N (MBN), soil available N, HwC and HwN increased upon application of Ba and Li. No quantitative relationship was observed between application of organic material and MBC, MBN or soil available N. A positive line ar correlation was observed between MBN and HwC but not between MBN an d soil available N. Among the various soil neutral sugar C, xylose C ( Xyl) content in Ba plots showed a remarkable increase but mannose C (M an) did not differ among Fer (fertilizer), Ba or Li plots. Soil neutra l sugar C had a positive linear correlation with soil available NI MBN and HwC. The proportion of MBN:TN is positively correlated with the X yl/Man ratio. The in crease in the proportion of MBN in SOM seems to o ccur with the increase of SOM derived from plant debris.