ポット栽培のアカマツ苗に施肥された窒素の収支

概要

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The distribution of ^<15>N applied to Japanese red pine seedlings were traced in a pot experiment. Tagged ammonium sulfate was applied to three groups of pots of the seedlings, A, B, and C, at three different times. Applications were made in April, July, and September for Groups A, B, and C, respectively. Untagged nitrogen was applied in supplemental pots. Group A was sampled in July, September, and December. Group B was sampled in September and December, and Group C was sampled in December. Total nitrogen and ^<15>N concentration were determined by the KJELDAHL method, and the optical spectroscopic method, respectively. Seventy-two to 84% of the applied nitrogen was recovered in the first samplings that were made two or three months after each application, and the recovery rates did not decrease in the following samplings. The residue of the applied nitrogen was converted into a nitrate form in the soil. Soil pH decreased with time. The seedlings absorbed both ammonium and nitrate nitrogen, but between September and December ammonium nitrogen was absorbed in preference to nitrate nitrogen. About 50% of the nitrogen applied at each stated time was taken up by the seedlings during the growing season.
一般社団法人日本森林学会の論文
1986-04-25