Carbon and nitrogen mineralization of harvesting residues of Pinus sylvestris L. during aerobic laboratory incubation
1995
Pluth, D. (Alberta Univ., Edmonton (Canada). Dept. of Soil Science) | Noemmik, H. | Wiklander, G. | Larsson, K. | Eriksson, A.
The carbon and nitrogen mineralization dynamics of Pinus sylvestris L. harvesting residues, when mixed with an acidic, nitrifying fen peat, were studied during aerobic, laboratory incubation at 20 deg C over 12 weeks. Green needle, brown needle and fine root showed a pattern of curvilinear decline in C mineralizaiton rate with time. The total amounts of C mineralized from those residues, expressed as a percentage of their initial C content, were 52, 41 and 16%. Stem bark and stem wood mineralized more slowly; the value for stem bark was near zero. With the exception of stem bark, the harvesting residues enhanced the mineralization of added 14C-labelled glucose. During the early decomposition of pine residues, the degree of net N immobilization of mineral N was related to the initial C/N ratio or total N concentration of the residues and net N mineralization was negatively correlated with mineralization of C. The remineralization rate of freshly immobilized N was estimated as seven times faster than the mineralization rate of more recalcitrant native N from the fen peat. The added pine residues did not influence measurably the nitrification capacity of the fen peat.
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