Temporal Variation of N Isotopic Composition of Decomposing Legume Roots and Its Implications to N Cycling Estimates in Tracer Studies in Agroforestry Systems
Figure 1
Model of residue decomposition and subsequent uptake of residue N by a recipient plant. Each pool is divided into 14N and 15N. Subscripts R1 and R2, B1 and B2, and H1 and H2 refer to the pools related to the two residue fractions in the residue, microbial biomass, and humified organic matter, respectively. Parameters k and are decomposition rate constants for residue and microbial biomass, respectively, Y is assimilation yield of C from residue by microbial biomass, and h is humification rate of microbial biomass. Parameter u is N uptake rate by the recipient plant, and its subscripts SR and SN refer to the uptake rates from the two soil inorganic pools (Table 2). Parameter Sf is N source factor which determines the relative N uptake rates from the two soil N pools. Parameter is mineralisation rate for soil organic N. Pools and processes indicated with bold lines are simulated according to Nicolardot et al. [24].
