Relationship between neutral sugars and the degree of humification in andisols

Abstract

We investigated the relationship between the amounts of neutral sugar carbon (NSC) and total carbon content (TC) or the degree of humification of soil organic matter (SOM) using 14 Andisols in Japan. The amounts of 7 kinds of NSC, TC content and the degree of humification of humic acids expressed as RF values were determined. Positive linear correlations were observed between the amount of every kind of NSC and TC Especially the amount of mannose carbon which was likely to be adsorbed on the mineral components in soil and is considered to be mainly of microbial origin was highly correlated with TC (r = 0.912**). However the correlation of cellulose-type glucose-C which was assumed to be mainly of plant origin was less significant (r = 0.603*) compared with other kinds of NSC. The proportion of total NSC (TNSC) in TC was negatively correlated with RF values (r=− 0.623*). Furthermore the proportion of TNSC in humic acid carbon was also negatively correlated with RF values (r= −0.891**). In a conclusion, our study showed that; 1) Neutral sugars accumulate along with the increase in the accumulation of SOM. However the relationship seems to be influenced by different rates of accumulative characteristics in each sugar. 2) The lower the proportion of neutral sugars in SOM, the higher the degree of humification. On the other hand, we could not determine whether plant material origin or microbial product origin was more responsible for the phenomenon obserbed. © Taylor & Francis Group, LLC.