Input and Output Flux of Carbon and Nitrogen in Decomposing Leaf Litter of Japanese Cedar

概要

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In order to analyze the pattern of loss of carbon and nitrogen from decomposing leaf litter of Japanese cedar (Cryptomeria japonica D. Don), the carbon and nitrogen influx and outflow were measured over a period of 60 months. The fresh leaf litter was cut into pieces, put into a plastic pot with an outlet in the lowermost part and set on the forest floor. The rainwater passing through the litter layer was collected every time, and the pH and amount of carbon and nitrogen were measured. An empty pot was set beside the plastic pot and the rainwater (throughfall) was also collected. After the rain passed through the litter layer the pH increased by a maximum of 2.9, presumably due to the leaching of cations such as calcium and magnesium. At the very early stage of the decomposition, the leaching of a relatively large amount of carbon and nitrogen followed by periodical in- and output flux was observed. The measurement of ammonium- and nitrate-N showed that at first these inorganic forms accumulated in the litter. On the third year of the decomposition, the leaching pattern of nitrate-N changed from accumulation to release. Thus, it was concluded that the leaf litter of Japanese cedar remained for 2 yr (or two growing seasons) in the F1 or accumulation stage of inorganic nitrogen, and that in the third year it entered the F2 or mineralization stage.
社団法人日本土壌肥料学会の論文