NUTRIENT DYNAMICS AND LIGNOCELLULOSE DEGRADATION IN DECOMPOSING QUERCUS-SERRATA LEAF-LITTER

The litter mass loss, concentration and mass of some major nutrient el ements, degradation of lignin and cellulose in decomposing Quercus ser rata Murray leaf litter were monitored for 3 years using the litterbag method. The mobility of elements during the course of the study was i n the order of: K > P > C > Mg > Ca > N. Three patterns of nutrient dy namics were observed: (i) concentration increased while mass decreased (N, Mg and Ca); (ii) concentration and nutrient mass decreased (K and C); and (iii) both concentration and mass had fluctuated (P). The C t o element ratio tended to increase as the element was released, and de creased as the element was retained. Nitrogen mobility in relation to carbon was characterized by three phases: (i) initial release; (ii) ac cumulation and (iii) final release. The decay rate (k) calculated from 0-6 months period was overestimated for an average annual rate while those of 0-36 months fit the negative single exponential model (Adj. r (2) = 0.99) better than shorter periods. For lignin, the concentration had increased then decreased but tended to stabilize after 1 year whi le the lignin mass had continuously decreased throughout the study per iod. During the first 9 months, both the concentrations and mass oi ce llulose had fluctuated but declined thereafter. The amounts of N had i nitially increased but declined after 1 year; P had fluctuated while I t, Ca, Mg and C had decreased throughout the study. N and C/N ratio ex erted strong influence on mass loss during the first 24 months but the influence of lignin emerged after 24 months.