Carbon and nitrogen transformations in soil are microbially mediated processes that are functionally related. The fate of C and N was monitored in a clay-textured soil (Typic Haplocambid) which was either unamended (control) or amended with various plant materials at the rate of 10 g residue C/kg soil. To evaluate C mineralization, soils were incubated for 46 days under aerobic conditions. Nitrogen mineralization/immobilization was evaluated at the end of eight-week incubation experiment. All CO<sub>2</sub> evolution data conformed well to a first-order kinetic model, C<sub>m </sub>= C<sub>0</sub> (1 – e<sup>–Kt</sup>). The product of K and C<sub>0 </sub>(KC<sub>0</sub>) was significantly correlated with some chemical and biochemical properties of the plant residues, including N concentration (r = 0.83, P < 0.001), C:N (r = –0.64, P < 0.05) and lignin:N (r = –0.81, P < 0.001). Among the plant residue composition characteristics, N concentration (r = 0.96, P < 0.001), C:N (r = –0.69, P < 0.01) and lignin:N (r = –0.68, P < 0.01) were significantly correlated with the net rates of N mineralization/immobilization (N<sub>m/i</sub>).
Impacts of long-term plant residue management on soil organic matter quality, Pseudomonas community structure and disease suppressiveness
