Roots mine light and heavy POM for litter N
Root ingrowth selectively mined N from organic matter in both POM pools. Root ingrowth preferentially reduced the litter N remaining in light and heavy POM fractions (Fig. 2b, green light POM N is 55 % lower with root ingrowth, p<0.001; blue heavy POM N is 26% lower with root ingrowth, p<0.01). In turn, root ingrowth increased the C:N ratio of litter-derived SOM in light POM (Fig. 4a, p<0.001) and heavy POM (Fig. 4b, p<0.001).